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  • 1980-1984  (813)
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  • 201
    Electronic Resource
    Electronic Resource
    Radikalionen, 47. Notiz: Die Strukturänderung während der Einelektronen-Oxidation von Bis(dimethylamino)disulfid (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2632-2639 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical Ions, 47. Note on the Structural Change during the One-Electron Oxidation of Bis(dimethylamino) DisulfideOn one-electron oxidation, (H3C)2N—S—S—N(CH3)2 considerably changes its structure: where as the neutral molecule according to the ionization band pattern of the PE spectrum displays N and S lone pairs perpendicular to each other, as ESR spectroscopic comparison suggests a planarized skeleton for the radical cation. INDO closed and open shell total energy hypersurfaces for the model compounds H2N—S—S—NH2 and support the discussion of the spectra.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140725
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  • 202
    Electronic Resource
    Electronic Resource
    Über Metallalkyl- und -aryl- Verbindungen, XXVII. Darstellung und Kristallstruktur von Bis(phenylethinyl)bis-(N,N,N′,N′-tetramethylethylendiamin)magnesium, Mg(C≡CPh)2(tmeda)2 (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2640-2643 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Alkyl and Aryl Compounds, XXVII. Preparation and Crystal structure of Bis(phenylethynyl)bis(N, N, N′,N′-tetramethylethylenediamine)magnesium, Mg(C≡CPh)2(tmeda)2The title compound has been prepared from bis(phenylethynyl)magnesium and N, N, N′,N′-tetramethylethylenediamine (tmeda) and investigated by X-ray diffraction methods (orthorhombic space group Cmcm, Z = 4, 696 (reflections, R = 0.049). It represents a first example of an organomagnesium compound with octahedral coordination of the central atom. The phenylethynyl ligands are in trans position.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140726
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  • 203
    Electronic Resource
    Electronic Resource
    Darstellung und Eigenschaften von B(OTeF5)3, Cs[B(OTeF5)4] und B(OTeF5)3 · CH3CN (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2644-2648 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Properties of B(OTeF5)3, Cs[B(OTeF5)4], and B(OTeF5)3·CH3CNInteraction of BCl3 with HOTeF5 affords B(OTeF5)3 (1) in quantitative yield. This compound reacts with CsOTeF5 to give Cs[B(OTeF5)4] (2) and with acetonitrile to form the adduct B(OTeF5)3·CH3CN (3). Thermolysis of 1 above 130°C leads to TeOF4 which cannot be isolated, but dimerizes to 4 and polymerizes to F5Te[OTeF4]nOTeF5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140727
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  • 204
    Electronic Resource
    Electronic Resource
    Synthese von Arginin-haltigen Peptiden mit dem Kondensationsreagenz Tris(dimethylamino)phosphan/Hexachlorethan/1-Hydroxybenzotriazol (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2649-2652 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Arginine Containing Peptides by Means of the Condensing Reagent Tris(dimethylamino)phosphane/Hexachloroethane/1-HydroxybenzotriazoleThe combination of the title reagents is well suited for building up protected oligopeptides contatining arginine.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140728
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  • 205
    Electronic Resource
    Electronic Resource
    Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, XVI. Fünfgliedrige Wolfram-, eisen- und nickelhaltige Metallacycloalkane (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2653-2657 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Properties of, and Reactions with, Metal-Containing Heterocycles, XVI1) Five-Membered Tungsten-, Iron-, and Nickel-Containing MetallacycloalkanesThe metallacyclopentanes, (3a-c) [m = 1-3: LnM = h5-C5H5Ni (3a), h5-C5H5Fe (3b), h5-C5H5W (3c)] are obtained by reductive cycloelimination of the complexes Ln(OC)m-1M(X)PPh2[CH2]3Cl (2a-c) with sodium amalgam. 3b is also formed from h5-C5H5-(OC)2FeBr (1b) and PPh2[CH2]3MgCl. 3a,b insert SO2 into their M—C σ bond to give the cyclic S-sulfinates (4a,b).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140729
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  • 206
    Electronic Resource
    Electronic Resource
    N-Ethylcarboxamide von lyxo-Purinnucleosiden (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2947-2955 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Ethyl lyxo Purine Nucleoside CarboxamidesMethyl-2,3-O-isopropylidene lyxuronate (1a) was transformed into 1 α-chloro-1-desoxy-N-ethyl-2,3-O-isopropylidene lyxuronamide (2d). Direct molten state condensation of 2d with silylated 6-chloro- and 2,6-dichloropurine (4a, b) yields mainly N-ethyl-N-9-purinyl nucleoside carboxamides with α and β-configuration (5a, b and 6a, b). The structure of these compounds was established from 1H- and 13C-NMR data.
    Notes: Aus 2,3-O-Isopropylidenlyxuronsäure-methylester (1a) wurde was 1 α-Chlor-1-desoxy-N-ethyl-2,3-O-isopropylidenlyxuronamid (2d) hergestellt. Schmelzkondensation mit silyliertem 6-Chlor- und 2,6-Dichlorpurin (4a, b) lieferte im wesentlichen die N-9-verknüpften α- und β-konfigurierten N-Ethyl-lyxo-purinnucleosidcarboxamide 5a, b und 6a, b. Die Struktur der erhaltenen Nucleoside wurde 1H- und 13C-NMR-spektroskopisch gesichert.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140904
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  • 207
    Electronic Resource
    Electronic Resource
    Reaktion von Acetyl-Übergangsmetallkomplexen mit Phosphor-Yliden - ein weiteres Beispiel zur Halogenid/Metallat-Analogie (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2956-2970 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Acetyl Transition Metal Complexes with Phosphorus Ylides - a Further Example of Halide/Metalate AnalogyThe reaction of the acetyl metal complexes LnM—C(O)CH3 [LnM = C5H5(CO)2Fe, C5H5(CO)3Mo, C5H5(CO)2[P(CH3)3]Mo] with the phosphorus ylides (CH3)3P=CH2, C2H5(CH3)2P=CH2, (C2H5)3P=CHCH3 and (C4H9)3P=CH2 in the ratio 1:2 yields the corresponding acetyl-substituted ylides R3P=CR′C(O)CH3 3a-d (R = CH3, C2H5, n-C4H9; R′ = H, CH3) and phosphonium metalates [R4P][MLn]4a-d, 6a, b via heterolysis of the Fe—C-σ-bond and transylidation. With CH3C(O)Cl an analogous way of reaction is observed, which however can be repeated to give the diacetyl ylides R3P=C(COCH3)2 8a, b (R = Ch3, n-C4H9). The new compounds are characterized by spectroscopic methods (NMR, IR) and further reactions.
    Notes: Die Umsetzung der Acetyl-Metallkomplexe LnM—C(O)CH3 [LnM = C5H5(CO)2Fe, C5H5(CO)3Mo, C5H5(CO)2[P(CH3)3]Mo] mit den Phosphor-Yliden (CH3)3P=CH2, C2H5(CH3)2P=CH2, (C2H5)3P=CHCH3 und (C4H9)3P=CH2 im Verhältnis 1 : 2 liefert unter Heterolyse der Fe—C-σ-Bindung und Umylidierung die entsprechenden Acetyl-Ylide R3P=CR′C(O)CH3 3a-d (R = CH3, C2H5, n-C4H9; R′ = H, CH3) und Phosphonium-metallate [R4P][MLn] 4a-d, 6a, b. Mit CH3C(O)Cl wird ein analoger Reaktionsverlauf nachgewiesen, der sich aber wiederholen und zu Diacetyl-Yliden R3P=C(COCH3)2 8a, b (R = CH3, n-C4H9) führen kann. Die neuen Verbindungen werden spektroskopisch (NMR, IR) und durch Folgereaktionen charakterisiert.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140905
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  • 208
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    Darstellung und Reaktionen von kationischen Chlorobis(phosphan)platin(II)-Komplexen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2971-2978 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Reactions of Cationic Chlorobis(phosphane)platinum(II) Complexes[(R3P)2Pt(Cl)H2O]+BF-4 (1) and (R3P)2Pt(Cl)OSO2CF3 (2) have been prepared by abstraction of chloride from cis-(R3P)2PtCl2 using tetrafluoroboric acid or trifluoromethanesulfonic acid, respectively. The protons of the aqua ligand in 1 form hydrogen bridges to the BF-4 anion. The acidic complexes 1 and 2 are useful starting materials for new platinum(II) complexes. HCO-3 neutralizes 1 to form the carbonato complex (Et3P)2PtO2CO (5). The heterogenous reaction of 2a with glycinate gives the cationic chelate complex (6). The coordinated water of 1 is easily substituted by other ligands, e. g. phosphanes. The chloro-bridged complexes [(R3P)2PtCl2Pt(PR3)2]2+ are formed by treatment of 1 or 2 with ethers.
    Notes: [(R3P)2Pt(Cl)H2O]+BF-4 (1) und (R3P)2Pt(Cl)OSO2CF3 (2) (R = Et, n-Bu, Ph; 2 PR3 = Ph2PCH2CH2PPh2) werden durch Chlorid-Abstraktion aus cis-(R3P)2PtCl2 mit Tetrafluoroborsäure bzw. Trifluormethansulfonsäure erhalten. Die Protonen des Aqua-Liganden von 1 bilden Wasserstoffbrücken zum BF-4-Anion aus. Die sauren Komplexe 1 und 2 lassen sich zur gezielten Synthese neuer Platin(II)-Komplexe nutzen. In heterogener Reaktion entsteht aus 2a mit Glycinat der kationische Chelatkomplex (6). Hydrogencarbonat neutralisiert 1 unter Bildung des Carbonatokomplexes (Et3P)2PtO2CO (5). Das koordinierte H2O in 1 läßt sich leicht durch andere Liganden, z. B. Phosphane, ersetzen. 1 und 2 bilden in Ethern die Chloro-verbrückten Dikationen [R3P)2PtCl2Pt(PR3)2]2+.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140906
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  • 209
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    Metall-Bor-Verbindungen, 13. Zur Synthese und Reaktivität einiger (Trimethylstannyl)borane (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3056-3062 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal-Boron Compounds, 13. Synthesis and Reactivity of some (Trimethylstannyl)boranes2)The preparation of some amino(trimethylstannyl)boranes and their chemical properties are described. With Me3SnLi (Me = CH3) as a reagent only the synthesis of Me3SnB(NR2)2 (1a, b), Me3SnBCl(NR2) (2a, b), and (Me3Sn)2BNR2 (3b) was achieved. The stannylboranes Me3SnB(NR2)2 show astonishing thermal stability. Their Sn—B bonds are broken by hydrogen, the halogens, and chalcogens as well as by alcohols. HCl cleaves the B—N bond.
    Notes: Die Darstellung einiger Amino(trimethylstannyl)borane und deren chemische Eigenschaften werden beschrieben. Mit Me3SnBCl(NR2) (1a, b) und Me3SnBCl(NR2) )2a, b) (Me3Sn)2BNR2 (3b). Die Stannylborane Me3SnB(NR2)2 sind thermisch erstaunlich stabil. Ihre Sn—B-Bindungen werden von Wasserstoff, den Halogenen, Chalcogenen und Alkoholen gespalten, während HCl die B—N-Bindung öffnet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140912
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  • 210
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    Radikale durch Oxidation von λ3-Phosphorin-Derivaten (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3019-3023 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radicals by Oxidation of λ3-Phosphorin DerivativesThe first ESR spectra, which are observed when 2,4,6-trisubstituted λ3-phosphorins 1a-c are oxidized electrolytically or with dichlorodicyanoquinone (DDQ) in dichloromethane or tetracyanoethene (TCNE) in 1,2-dimethoxyethane, are not - as formerly supposed - those of λ3-phosphorin cation radicals 2a-c. They are secondary radicals of the λ4-phosphorin-type 3 which are produced from the very short living radicals 2 by addition of water from the solvent. Oxidation of 1c in dichloromethane/methanol with DDQ affords the 2,4,6-tri-tert-butyl-1-methoxy-λ4-phosphorin radical 3′c. Further oxidation of the radicals 3 produces the very stable radicals 7a-c, once again by addition of water and deprotonation. Their ESR spectra are very similar to those of the „neutral radicals“, described in the precedent paper, which are formed by the electrolytic oxidation of 1,1-dimethoxy-λ5-phosphorins in dichloromethane in the presence of lithium bromide or by oxidation with lead tetrabenzoate and which are the methyl esters of 7.
    Notes: Die ersten ESR-Spektren, die man bei der elektrolytischen Oxidation von 2,4,6-trisubstituierten λ3-Phosphorinen 1a-c, der Oxidation mit Dichlordicyanchinon (DDQ) in Dichlormethan oder der mit Tetracyanethen (TCNE) in 1,2-Dimethoxyethan beobachtet, sind nicht, wie früher angenommen, die der λ3-Phosphorin-Kationradikale 2a-c. Es sind die von Folgeradikalen vom λ4-Phosphorintyp 3, die aus den sehr kurzlebigen Radikalen 2 durch Addition von Wasser aus dem Lösungsmittel entstehen. Methanolzusatz zum Dichlormethan bei der Oxidation von 1c mit DDQ führt zum 2,4,6-Tri-tert-butyl-1-methoxy-λ4-phosphorin-Radikal 3′c. Bei weiterer Oxidation der Radikale 3 entstehen unter erneuter Addition von Wasser und Deprotonierung die sehr beständigen Radikale 7a-c. Ihre ESR-Spektren unterscheiden sich nur wenig von denen der in der vorstehenden Mitteilung beschriebenen „Neutralradikale“, die bei der elektrolytischen Oxidation aus 1,1-Dimethoxy-λ5-phosphorinen in Dichlormethan bei Anwesenheit von Lithiumbromid oder der Oxidation mit Bleitetrabenzoat entstehen und die den Methylestern von 7 entsprechen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140909
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  • 211
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    Beiträge zur Chemie des Bors, 120. Tetraorganyldiborane(4): Darstellung und Stabilität (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3044-3055 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 120. Tetraorganyldiboranes(4): Preparation and Stabilitytert-Butylation of B2(OCH3)4 by LiC(CH3)3 proceeds via [(CH3)3C](CH3O)B—B(OCH3)[C(CH3)3] (1) to give tri-tert-butylmethoxydiborane(4) (2). Tetraalkylation of B2(OCH3)4 is achieved by isopropyllithium; no reaction intermediates were found in this case. Al(C2H5)3 reacts with B2(OCH3)4 to give B2(C2H5)4 which is stable only below - 30°C. On the other hand the CH3O group in 2 is replacable by CH3, and the CH3O groups in 1 by ethyl groups. Thus, product control by steric factors is evident. - The thermal stability of tetraorganyldiboranes(4) is controlled by the steric screening of the boron atoms: tetraisopropyldiborane(4) decomposes slowly at room temperature, tetraethyldiborane(4) rapidly at - 20°C.
    Notes: Die tert-Butylierung von B2(OCH3)4 mit LiC(CH3)3 führt über die Stufe [(CH3)3C](CH3O)B—B-(OCH3)[C(CH3)3] (1) zu Tri-tert-butylmethoxydiboran(4) (2). Die Tetraalkylierung von B2(OCH3)4 gelingt mit Isopropyllithium; Isopropylmethoxydiboran(4)-Zwischenstufen sind nicht faßbar. Al(C2H5)3 reagiert mit B2(OCH3)4 zu dem nur unterhalb von - 30°C stabilen B2(C2H5)4. Die CH3O-Gruppe in 2 ist gegen eine CH3-Gruppe ersetzbar, die CH3O-Gruppen von 1 gegen Ethylgruppen. Produktkontrolle erfolgt somit durch sterische Effekte. - Die thermische Stabilität der Tetraorganyldiborane(4) wird von der sterischen Abschirmung der Boratome gesteuert: Tetraisopropyldiboran(4) zersetzt sich langsam bei Raumtemperatur, Tetraethyldiboran(4) rasch bei - 20°C.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140911
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  • 212
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    Beiträge zur Chemie des Bors, 119. Darstellung und Struktur von Tris[bis(organylthio)boryl]aminen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3024-3043 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 119. Synthesis and Structure of Tris[bis(organylthio)boryl]aminesNMR data of Tris[bis(organylthio)boryl]amines, N[B(SR)2]3, prepared by two different routes, indicate chemically equivalent RS groups in solution. The rather weak screening at boron and nitrogen agrees with the competition of three boron atoms for the lone pair of electrons at nitrogen, e.g. weak BN-π-bonding. - The equivalence of the RS groups is lost in the solid state. One(RS)2B group in each of the compounds 1-4 is strongly twisted against the B3N plane, and following the series 1, 2, 4, and 3 the other two orient themselves more and more coplanarily to this plane. Accordingly, a relatively long BN bond (147-148 pm) is observed besides two shorter BN bonds (143-145 pm) in each of these compounds. This is experimental evidence for the dependence of the B—N distance from π-bond order and its angular dependence. In addition, the structures of the 1,3,2-dithiaborolan, the 1,3,2-benzodithiaborol, and the 1,3,2-dithiaborolene ring systems have been ascertained. Only the latter two posses planar rings. - Mass spectrometric fragmentation of the tris[bis(organylthio)boryl]amines proceeds with preferential retention of BN bonding. For instance, the molecular ion of 2 breaks apart by three successive eliminations of ethylene with formation of the radical cation of NB3S6+ (12), derived from a hitherto unknown tricyclic system.
    Notes: Tris[bis(organylthio)boryl]amine, N[B(SR)2]3, nach zwei verschiedenen Verfahren dargestellt, besitzen in Lösung nach NMR-Untersuchungen chemisch äquivalente RS-Gruppen. Die gefundene geringe Abschirmung des Bors und Stickstoffs steht in Übereinstimmung mit der Konkurrenz von drei Boratomen um das freie Elektronenpaar am Stickstoff, d. h. schwacher BN-π-Bindung. - Im festen Zustand der Verbindungen 1-4 ist dagegen jeweils eine der drei (RS)2B-Gruppen stark gegen die B3N-Ebene verdrillt, und in der Reihe 1, 2, 4 und 3 zunehmend stellen sich die beiden anderen koplanar zu dieser Ebene ein. Dementsprechend beobachtet man eine relativ lange (147-148 pm) neben zwei kürzeren BN-Bindungen (143-145 pm). Dies ist ein experimenteller Beleg für die Abhängigkeit des B—N-Abstands von der π-Bindungsordnung zwischen B und N und ihrer Winkelabhängigkeit. Zugleich wurde die Struktur des 1,3,2-Dithiaborolan-, des 1,3,2-Benzodithiaborol- und des 1,3,2-Dithiaborolen-Ringes ermittelt. Nur die beiden letztgenannten Heterocyclen besitzen ein planares Ringgerüst. Die massenspektrometrische Fragmentierung der Tris[bis(organylthio)boryl]amine verläuft bevorzugt unter Erhaltung der BN-Bindungen. Dabei zerfällt das Molekül-Ion von 2 vor allem unter sukzessiver Abspaltung von 3 mol Ethylen und Bildung des Radikal-Kations NB3S6+ (12), das sich von einem bisher unbekannten Tricyclus ableitet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140910
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  • 213
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    Bausteine von Oligosacchariden, XXX. Neue effektive β-Glycosidsynthese für Mannose-Glycoside Synthesen von Mannose-haltigen Oligosacchariden (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3102-3114 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, XXX. New Efficient β-Glycoside Synthesis of Mannose Glycosides Syntheses of Mannose Containing OligosaccharidesA new method was developed for the stereo selective synthesis of oligosaccharides containing a β-linked mannose-unit which were hitherto not available by direct synthesis. The glycoside synthesis is promoted by a silversilicate-catalyst which was precipitated on aluminium oxide. The trisaccharides 20 and 31 (see german summary) and the tetrasaccharide 33 were synthesized, demonstrating the advantages offered by block synthesis.
    Notes: Es wird eine neue Methode zur selektiven Synthese von Oligosacchariden mit β-verknüpfter Mannose-Einheit entwickelt, für deren direkte Gewinnung es bisher kein Verfahren gab. Als Katalysator dient ein auf Al2O3 niedergeschlagenes Silbersilicat. Es werden die Trisaccharide β-D-Man-(1→4)α-D-Gal-(1→4)-L-Rha (20) und sowie das Tetrasaccharid 33 synthetisiert. Hierbei werden die Vorteile der Blocksynthese demonstriert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140916
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    Ein cyclisches Carbodiphosphoran und eine offenkettige Vergleichsverbindung (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3063-3069 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Cyclic Carbodiphosphorane and an Open-chain Reference CompoundThe cyclic carbodiphosphorane 8 is prepared from bis(diphenylphosphino)methane (1) and 1,3-dibromopropane, via a diphosphonium salt 6 and a semiquaternary salt 7, through transylidation with salt-free trimethyl methylene phosphorane. The structure is established by 1H-, 13C-, 31P-NMR and mass spectrometry, as well as by X-ray diffraction. Reprotonation with anhydrous HCl regenerates the diphosphonium salt 6. With tetrahydrofuran-borane, 8 is converted into a 1:1-borane complex 9, with the BH3 acceptor attached to the double-ylide carbon bridge. Methylation with CH3I occurs in the same position (10). 1:1-complexes (11, 12) are also formed with dimethylzink and -cadmium. The products are probably dimeric and show a rapid CH3-exchange in solution. - The already known open-chain analogue CH3(C6H5)2P=C=P(C6H5)2CH3 (4) resembles 8 in many respects, including the molecular structure. In the coordination interaction with metals a metalation in the CH3-groups in strongly favoured, however, as it is again shown in the nickel complex 5.
    Notes: Aus Bis(diphenylphosphino)methan (1) und 1,3-Dibrompropan wird über ein Diphosphoniumsalz 6 und ein Semiquartärsalz 7 durch Umylidierung mit salzfreiem Trimethylmethylenphosphoran das cyclische Carbodiphosphoran 8 dargestellt. Der Strukturbeweis gelingt über 1H-, 13C-, 31P-NMR-und Massenspektrum sowie durch eine Röntgenbeugungsanalyse. Durch wasserfreien Chlorwasserstoff wird das Diphosphoniumsalz 6 zurückgebildet. Mit Tetrahydrofuran-Boran wird ein 1:1-Komplex 9 erhalten, der den BH3-Akzeptor am Doppelylid-Brückenkohlenstoffatom gebunden hat. In gleicher Position erfolgt die Methylierung mit Methyliodid (10). Mit Dimethylzink und -cadmium entstehen 1:1-Komplexe (11, 12) vermutlich dimerer Struktur, die in Lösung raschen CH3-Austausch zeigen. - Das schon bekannte offenkettige Analogon CH3(C6H5)2P=C=P(C6H5)2CH3 (4) gleicht in vielen Eigenschaften, einschließlich seiner Molekülstruktur, dem Heterocyclus 8 Bei der Komplexbildung mit Metallen erfolgt hier jedoch bevorzugt Eintritt in die CH3-Gruppen. Der Nickelkomplex 5 ist dafür ein charakteristisches Beispiel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140913
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    Glycogen accumulation in the parathyroid gland of the rat after fluoride ingestion (1981)
    Springer
    Cell & tissue research 220 (1981), S. 125-130 
    Details
    ISSN: 1432-0878
    Keywords: Glycogen ; Parathyroid gland ; Fluoride ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parathyroid glands of young male rats given 150 ppm fluoride in their drinking water for 10 weeks were examined by transmission electron microscopy. As a result of fluoride ingestion, the parathyroid chief cells of the experimental animals accumulated glycogen in excess of that seen in control animals given distilled drinking water for the same time period. In the majority of active chief cells, glycogen granules were diffusely spread throughout the cytoplasm as single granules or in small deposits. Large aggregations of glycogen granules were also seen within intercellular spaces. Accompanying the increase in glycogen was a rise in the number and development of the organelles associated with protein synthesis and secretion. The accumulation of glycogen is similar to that in hyperparathyroidism caused by chronic stimulation and prolonged secretory activity of the parathyroid gland. The results of this study suggest that increased amounts of glycogen occur in hyperactive chief cells of the parathyroid in response to the ingestion of large doses of fluoride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209971
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    Morphometric analysis of the autophagic and crinophagic lysosomal systems in mammotropes throughout the estrous cycle of the rat (1981)
    Springer
    Cell & tissue research 220 (1981), S. 131-137 
    Details
    ISSN: 1432-0878
    Keywords: Rat ; Adenohypophysis ; Mammotropes ; Autophagic and crinophagic lysosomes ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The crinophagic and autophagic lysosomal systems were studied in mammotropes (prolactin secreting cells) of the adenohypophysis throughout the estrous cycle of the rat. By means of morphometric analysis, it was found that the volume of secondary autophagic lysosomes was usually greater than that of the crinophagic type. Although the volumes of both secondary autophagic and crinophagic lysosomes were minimal throughout proestrus and diestrus 2, the autophagic lysosomal volume per mammotrope was elevated during the estrous period. The volume of secondary crinophagic lysosomes per mammotrope increased during late estrus and remained elevated throughout early diestrus 1. Furthermore, there was an inverse relationship between the volume of mature secretory granules per cell and of the crinophagic system. These data suggest a role for lysosomes in the regulation of synthesis and secretion of prolactin by the adenohypophysis of the rat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209972
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    Cytochemical analysis of intracellular calcium distribution in the anterior pituitary of the rat (1981)
    Springer
    Cell & tissue research 220 (1981), S. 191-200 
    Details
    ISSN: 1432-0878
    Keywords: Rat ; Pituitary ; Calcium ; Pyroantimonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to assign morphologic identities to previously distinguished functional calcium compartments in the anterior pituitary of the rat, we employed the potassium pyroantimonate technique for cation localization. Tissues were incubated for In at 37°C in control medium; with 10mM theophylline; or with depolarizing amounts of potassium. Precipitate was quantified on photomicrographs of tissue prepared for electron microscopy with a Talos Systems Digitizer. The nature of the electron dense precipitate was dependent on the experimental state of the tissue. Treatment with 5 mM EGTA abolished the dense precipitate. Electron microprobe analysis also confirmed that calcium was the predominant cation in the observed precipitate. The most significant changes in precipitate deposition occurred along the plasma membrane, the limiting membrane of secretory granules and within mitochondria. Dense precipitate was present along the plasma membrane only in cells treated with potassium. Control tissue exhibited higher levels of precipitate associated with the limiting membrane of secretory granules than either theophylline-treated or potassium-treated tissue. Mitochondria contained more precipitate in potassium-treated tissue than in controls; the mitochondria of theophylline-treated tissue contained intermediate levels of precipitate. Addition of either theophylline or depolarizing amounts of potassium has been associated with hormone secretion in anterior pituitary tissue of normal rats. Kinetic studies in our laboratory indicate that intracellular calcium shifts occur. The pyroantimonate technique is useful in verifying morphologically the calcium compartments involved in shifts in intracellular calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209977
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    The relationship between the nuage and the chromatoid body during spermatogenesis in the Rat (1981)
    Springer
    Cell & tissue research 215 (1981), S. 425-430 
    Details
    ISSN: 1432-0878
    Keywords: Nuage ; Chromatoid body ; Spermatogenesis ; Germ cell determination ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytoplasmic structures ultrastructurally similar to the nuage are present in the cytoplasm of all spermatogenic cells in adult rats. The nuage is a discrete organelle which should not be confused with the chromatoid body. In step 7–8 spermatids transient contact is established between the nuage and the chromatoid body. This indicates a very specific recognition of the nuage by the chromatoid body. It is suggested that the nuage and the chromatoid body are separate cell organelles the functions of which are somehow related to each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239125
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    Effects of pimozide on the ultrastructure of the pars intermedia in the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 397-403 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; MSH-cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars intermedia of the rat. The animals received 100 μg/100 g pimozide daily for 2, 5, 10, 15, and 20 days. Pimozide induces ultrastructural changes after 5 days of treatment. About 50% of the MSH-cells display characteristics of stimulation. Their cytoplasm is partially or totally depleted of secretory granules. The rough endoplasmic reticulum displays a network of interconnecting cisternae and ribbon-like structures. The well-developed Golgi complexes exhibit numerous dilatations of their cisternae, which contain electron-dense material. The nerve endings are not altered. Twenty days after treatment, the above-described changes have not decreased in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in some MSH-cells, most probably the elements underlying an inhibitory dopaminergic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233589
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    Somatostatin-immunoreactive fiber projections into the brain stem and the spinal cord of the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 531-552 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin fiber projections ; Brain stem ; Spinal cord ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of the PAP-immunohistochemical staining technique with serial sections, somatostatin-immunoreactive fiber projections into the brain stem and the spinal cord are described. These projections originate in the periventricular somatostatin-immunoreactive perikarya of the hypothalamus and form three main pathways: (1) along the stria medullaris thalami and the fasciculus retroflexus into the interpeduncular nucleus; (2) along the medial forebrain bundle into the mammillary body; and (3) via the periventricular gray and the bundle of Schütz into the midbrain tegmentum. Densely arranged immunoreactive fibers and/or basket-like fiber terminals are observed within the following afferent systems: somatic afferent systems (nucleus spinalis nervi trigemini, substantia gelatinosa dorsalis of the entire spinal cord), and visceral afferent systems (nucleus solitarius, regio intermediolateralis and substantia gelatinosa of the sacral spinal cord). These projections form terminals around the perikarya of the second afferent neuron. Perikarya of the third afferent neuron are influenced by somatostatin-immunoreactive projections into the auditory system (nucleus dorsalis lemnisci lateralis, nucleus corporis trapezoidei). Furthermore, a somatostatin-immunoreactive fiber projection is found in the ventral part of the medial accessory olivary nucleus, in nuclei of the limbic system (nucleus habenularis medialis, nuclei supramamillaris and mamillaris lateralis) and in the formatio reticularis (nucleus Darkschewitsch, nuclei tegmenti lateralis and centralis, nucleus parabrachialis lateralis, as well as individual perikarya of the reticular formation). Targets of these projections are interneurons within interlocking neuronal chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219362
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    Synaptic input to the axon hillock and initial segment of inhibitory interneurons in the cerebellar cortex of the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 553-562 
    Details
    ISSN: 1432-0878
    Keywords: Axon hillock ; Interneurons ; Cerebellar cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The axon hillock (AH) and initial segment (IS) of 10 Golgi neurons and 6 basket cells in the cerebellar cortex of the rat were investigated by electron microscopy using serial sections. An average of 10.4 and 11.3 synaptic terminals were observed to establish synaptic contact with the axon hillock region of Golgi and basket cells, respectively. Most of these terminals were identified as the varicosities of the ascending parallel fibers. It is suggested that the focal innervation of AH regions represents an excitatory input pattern which is basically different from the randomly distributed, huge, parallel-fiber input onto the dendritic trees of Golgi and basket cells. In contrast to Golgi and basket neurons, no accumulation of parallel-fiber synapses was observed around the AH of stellate cells. The IS proper of the three neuronal types were devoid of true axo-axonal synapses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219363
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    Intercellular channels in the pars tuberalis of the rat hypophysis and their relationship to the subarachnoid space (1981)
    Springer
    Cell & tissue research 218 (1981), S. 345-354 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysis ; Pars tuberalis ; Intercellular channels ; Subarachnoid space ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A system of intercellular channels is described in the pars tuberalis (PT) of the female rat. These spaces are lined by all types of cells found in the PT and are not sealed off by tight junctions. Ventrally and dorsally, the intercellular spaces open toward the basement membranes separating the PT from (i) the subarachnoid space, and (ii) the perivascular space of the portal capillaries, respectively. These intercellular channels differ from the follicles, which are also found in the PT, being lined by a particular type of cell. In a second group of female rats an epoxy mixture was injected into the third ventricle; 10 min thereafter horseradish peroxidase was infused into the cisterna magna. After processing the brain for the demonstration of exogenous peroxidase, it was found that the tracer had reached the subarachnoid space adjacent to the hypothalamus and entered into all ventricular cavities with the exception of the infundibular recess. Under these experimental conditions it was found that the tracer fills all intercellular channels of the PT, thus indicating that there is no barrier between the subarachnoid space and the PT. It is suggested that the subarachnoid space should be regarded as a probable route for the transport of trophic factor(s) and/or secretory product(s) of the PT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210349
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    Cells capable of uptake of horseradish peroxidase in some circumventricular organs of the cat and rat (1981)
    Springer
    Cell & tissue research 219 (1981), S. 85-92 
    Details
    ISSN: 1432-0878
    Keywords: Circumventricular organs ; Reticuloendothelial system ; Phagocytic cells ; Horseradish peroxidase ; Cat ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of mesenchymal cells distributed in some of the “hypendymal organs” of the circumventricular system in the cat and rat was demonstrated after intravenous injection of high doses of horseradish peroxidase. These cellular elements were observed in the vicinity of blood vessels of the organon vasculosum laminae terminalis, subfornical organ and area postrema. Electron-microscopically, these cells located between the basal laminae of the brain parenchyma and the blood capillaries show long cellular processes encircling fenestrated capillaries. Light and electron-microscopic examination revealed that this cell type is identical with the “horseradish peroxidase-uptake cells”, previously reported in the vicinity of the hypophysial portal system. Such phagocytic cells may be considered as a cellular component intervening between the brain parenchyma and the blood stream, playing a role in selective barrier functions in the above-mentioned circumventricular organs where a blood-brain barrier in the classical sense of the definition is lacking.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210020
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    A retinal projection to the lateral hypothalamus in the rat (1981)
    Springer
    Cell & tissue research 214 (1981), S. 257-269 
    Details
    ISSN: 1432-0878
    Keywords: Retinal projection ; Lateral hypothalamus ; Dendrites in optic tract ; Axodendritic synapses ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study presents evidence for a retinal projection to neurons in the lateral hypothalamic area (LHA) of the albino rat. In Golgi-Kopsch material dendrites from LHA-neurons are observed to extend through the supraoptic commissures into the optic tract. The presence of dendrites in the optic tract is confirmed by electron microscopy. Numerous axon terminals are observed forming asymmetric synaptic contacts with these dendritic profiles. Following bilateral enucleation, many of the preterminal axons and terminals in synaptic contact with dendrites in the optic tract demonstrate dark degeneration. After intraocular injection of horseradish peroxidase, there is marked labeling of preterminal axons and terminals in the optic tract. These observations indicate that LHA neurons receive a direct retinal projection from terminals making synaptic contact with dendrites of LHA-neurons extending into the optic tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249210
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    The temporo-spatial course of degeneration after cutting cortico-cortical connections in adult rats (1981)
    Springer
    Cell & tissue research 214 (1981), S. 303-321 
    Details
    ISSN: 1432-0878
    Keywords: Cortico-cortical connections ; Degeneration ; Time course ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult albino rats received callosotomies or lesions in the paracingular cortex. Between 12 h and 3 months after injury the structure and topography of the degeneration products were studied by light- and electron-microscopy. The degeneration process was quantified by television-image analysis applied to sections prepared according to a new technique that stains reliably degenerating terminals and lysosomes (Gallyas et al. 1980). All types of cortico-cortical connections show a multiphasic degeneration process: During a precursor stage a small number of dense bodies and mitochondrial granules are stained. These and the few early degenerating axon terminals are much more diffusely distributed than the large number of terminals that degenerate during the following period. The terminal degeneration shows a biphasic time course. One maximum appears at 2–7 days post operation, which corresponds to the well known direct consequence of axotomy. The second peak at 10–20 days post operation could be caused by transneuronal reorganization of the cortical connectivity. Terminal degeneration always begins along the borders between cortical regions and areas, but it may change its laminar and columnar distribution pattern during the second phase. The degeneration products that are phagocytosed by astrocytes seem to be removed by intracellular transport to their perivascular endfeet. The degeneration process ends with fiber degeneration which, especially in laminae I and VI, may form a separate peak after 20 days or more.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249214
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    Circadian alterations in tubular structures on the outer mitochondrial membrane of rat hepatocytes (1981)
    Springer
    Cell & tissue research 214 (1981), S. 519-527 
    Details
    ISSN: 1432-0878
    Keywords: Mitochondria ; Tubular structures ; Hepatocytes ; Circadian changes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of hepatocytes were examined at 11.00 h and 23.00h (light cycle: 06.00h–18.00h) in four adult male Wistar rats (AF/Han) per time period. 1. The volume density of mitochondria in the cytoplasm of hepatocytes obtained from peripheral parts of liver lobules shows a statistically significant difference between the two time periods examined. 2. Tubular structures arising from the outer mitochondrial membrane are clearly demonstrated. Their cisternae are continuous with the interspaces between outer and inner mitochondrial membranes. 3. These tubular structures often open directly into the cisternae of rough or smooth-surfaced endoplasmic reticulum (rER and sER) and form a “bridge” between the endoplasmic reticulum and mitochondria. 4. At 11.00 h, the rER connected with the tubular structures often possesses very few ribosomes; at 23.00 h, the amount of ribosomes on the rER is substantially greater. Furthermore, at 23.00h ribosomes are also occasionally found on the membranes of the tubular structures. 5. The incidence of tubular structures on the outer membrane of mitochondria varies significantly between the two time periods. 6. The changing pattern of the volume density of mitochondria in the cytoplasm parallels that of the incidence of the tubular structures, i.e., both are high during the active phase and low during the resting phase of the rat. 7. These results suggest that the tubular structures may play an important role in protein transport between the endoplasmic reticulum and mitochondria, and in the rearrangement of rER during a 24-h period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233492
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    Intraepithelial blood vessels in the vomeronasal neuroepithelium of the rat (1981)
    Springer
    Cell & tissue research 215 (1981), S. 465-473 
    Details
    ISSN: 1432-0878
    Keywords: Vomeronasal organ ; Olfaction ; Intraepithelial blood vessels ; Rat ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epithelial-vascular relationships are established during the development of the vomeronasal neuroepithelium of the rat. Special attention is given to the fine structure of the endothelial wall of intra-epithelial vessels, to ultrastructural aspects of the neuronal-vascular relationships, and to the appearance of inclusion bodies in the neuronal cells adjacent to these vessels. The neuronal perikarya surrounding the blood vessels are filled with highly developed smooth endoplasmic reticulum. Possible functional implications of the vascularization of the neuroepithelium of the vomeronasal organ in mediating olfacto-endocrine relationships are discussed. It is suggested that the intra-epithelial blood vessels are at least supportive and nutritive in nature, while their implication in an olfacto-endocrine connection remains obscure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233523
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    The rat pituitary cleft: A correlated study by scanning and transmission electron microscopy (1981)
    Springer
    Cell & tissue research 215 (1981), S. 515-529 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Rathke's cleft ; Ultrastructure ; Scanning electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary SEM reveals that the inner surface of the pituitary cleft is lined by a continuous layer of marginal cells possessing microvillous and ciliated apical surfaces. The ciliated cells are more numerous on the posterior side (toward the pars intermedia) than on the anterior side of the cleft (toward the pars distalis). In contrast small infoldings (crypts) were occasionally noted only on the marginal layer covering the distal part of the hypophysis. In some areas of the cleft the surface features of the marginal cells are rather similar to the epithelial cells populating the upper parts of the respiratory tract in their topography and distribution. In other regions they also show striking similarities with the ependymal cells (tanycytes) lining the lateral recesses of the 3rd ventricle and the infundibular process with which the pituitary cleft has a very close topographical relationship. The parenchymal cells of the pars distalis are closely related to the flattened marginal cells of the cleft. The intercellular spaces of the pars distalis form a three-dimensional labyrinthic series of cavities continuous with the submarginal spaces of the cleft. Further SEM and TEM results demonstrate that the majority of the microvillous marginal cells lining both sides of the cleft possess surface features such as bulbous protrusions, laminar evaginations and large cytoplasmatic vacuoles, which are very likely the expression of an active transport of fluids. On the basis of these results it is concluded that the fluid-like material (colloid) present in the pituitary cleft is mainly derived from the fluids contained in the lacunar spaces of the pars distalis. Thus, marginal cells by absorbing fluids from the cleft by active endocytosis, may transport to the pars intermedia material (or hormones) produced in the distal part of the gland and vice versa. The cilia present on many marginal cells, based on their 9+2 tubular pattern, possess a kynetic role. This is very similar to that shown by the ciliated cells of the ependyma lining the brain ventricles. The occurrence of ciliated cells within the pituitary parenchyma (mainly in the follicles) suggests that they probably arise from the ciliated cells populating the marginal layer of the cleft and with which the parenchyma cells are closely related.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233528
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    Ultrastructure of neurons in the ventromedial nucleus or the hypothalamus in ovariectomized rats with or without estrogen treatment (1981)
    Springer
    Cell & tissue research 217 (1981), S. 451-470 
    Details
    ISSN: 1432-0878
    Keywords: Ventromedial nucleus ; Ultrastructure ; Estrogen effects ; Secretory product ; Lordosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the ventrolateral and dorsomedial subdivisions of the ventromedial nucleus (VMN) of the hypothalamus was examined in ovariectomized/control and ovariectomized/estrogen-treated rats to compare neurons of these areas to other neurons (specifically the ventrolateral thalamus), and to determine the effects of estrogen on these cells. The neurons of the VMN contain a large nucleus with a prominent nucleolus, rough endoplasmic reticulum (RER), polysomes, a Golgi complex, coated, uncoated and dense-cored vesicles, lysosome-like bodies, inclusion bodies, multivesicular bodies, whorl bodies and myelin figures. Similar organelles were present in the neurons of the ventrolateral thalamus, although polysomes were more prominent, and the cells lacked dense-cored vesicles in the perikarya. Differences in the cells of the VMN between ovariectomized/control and ovariectomized/estrogen-treated rats included a more conspicuous stacking of the RER and greater number of dense-cored vesicles in the estrogen-treated group in both the ventrolateral and dorsomedial subdivisions. In both areas the differences were statistically significant, although more marked in the ventrolateral subdivision. In both VMN subdivisions, the increased stacking of the RER could be correlated with the greater number of dense-cored vesicles and may reflect increased biosynthesis of a secretory product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219357
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    Ultrastructural observations on rapid formation of neuro-muscular junctions in vitro (1981)
    Springer
    Cell & tissue research 217 (1981), S. 647-659 
    Details
    ISSN: 1432-0878
    Keywords: Cell culture ; Neuro-muscular junctions ; Short-term preparations ; Mouse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of neuro-muscular junctions (mouse, rat) from the time of first contact between neurons and myotubes in culture and the changes which lead to the formation of functional synaptic contacts have been investigated using light microscopy and ultrastructural techniques. An extensive basal lamina was present when the neuronal cell population was added to the developing myotubes in culture. The nerve cells were initially strongly attracted to each other and nerve cell aggregates formed rapidly. It was only when nerve fibres began to grow out of these aggregates to contact developing myotubes that changes within the cytoplasm of the two adjacent cells were observed. These developments included accumulations of filaments, membrane densities, mitochondria and large clear vesicles within both cells in the region of contact. In addition, collections of glycogen granules and an extensive membrane reticular complex were found within myotubes, and an extensive granular material filled many of the nerve processes. The basal lamina within the intercellular space appeared more electron-dense than elsewhere and was traversed by strands linking the two cell membranes. These features all appeared to be stages in the initial formation of neuro-muscular junctions. It was only after these events had occurred that presynaptic vesicles gradually appeared within the future nerve terminal. The results of this paper therefore support the view that synaptic transmission at developing mammalian neuromuscular junctions is not necessarily dependent on the presence of presynaptic vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219371
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    Morphological studies on neuroglia (1981)
    Springer
    Cell & tissue research 218 (1981), S. 75-86 
    Details
    ISSN: 1432-0878
    Keywords: Microglia ; Macrophages ; Chemical lesion ; Kainic acid ; Hippocampus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light-and electron-microscopic investigations of kainic acid-induced lesions revealed a marked macrophage response and “microgliocytosis”. The hematogenous origin of reactive elements, such as brain macrophages and “microglia-like reactive cells”, was demonstrated when blood phagocytes were labeled with carbon particles or horseradish peroxidase prior to induction of the kainic acid-lesion. The induced lesion showed a proliferation of microglial cells, which led to a state of “microgliocytosis” in the later stage of lesioning. Since it is now generally accepted that microglial cells in the state of “microgliocytosis” are derived from the “microglia-like reactive cells”, proliferated microglial cells in the brain lesions are probably of hematogenous origin. The relationships among the brain macrophages, the “microglia-like reactive cells” and the intrinsic microglial cells are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210092
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  • 232
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    Elastic fibers associated with collagenous fibrils surrounded by reticular cells in lymph nodes of the rat as revealed by electron microscopy after orcein staining (1981)
    Springer
    Cell & tissue research 220 (1981), S. 445-448 
    Details
    ISSN: 1432-0878
    Keywords: Rat ; Lymph node ; Reticular cell ; Reticular fiber ; Elastic fiber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy of the rat lymph node disclosed reticular cells in close association with bundles of collagenous fibrils 30–45 nm in diameter, and electron lucent “amorphous” substances surrounded by microfibrils 11 nm in diameter, with junctional complexes. The amorphous substances, distinctly revealed by orcein staining, and the microfibrils showed morphological characteristics of elastic fibers. Since elastase digestion of 2% glutaraldehyde fixed specimens induced the selective disappearance of the orcein-stainable substances, it was concluded that they are elastin. Elastin often had a close contact with the plasma membrane of reticular cells. It is suggested that reticular cells synthesize elastic fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210522
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  • 233
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    Electron microscopic study of immunoreactive LHRH perikarya with special reference to neuronal regulation (1981)
    Springer
    Cell & tissue research 220 (1981), S. 511-518 
    Details
    ISSN: 1432-0878
    Keywords: LHRH neuron ; Synapse ; Immunohistochemistry ; Electronmicroscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In early postnatal rats, immunoreactive LHRH perikarya in the preoptic area were studied by light and electron microscopy. Synaptic junctions were found between the immunoreactive perikaryon or its process, and the immunonegative nerve fibers. The significance of these synapses is discussed in relation to possible mechanisms by which the activities of LHRH neurons are regulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216754
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  • 234
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    Autoradiographic localization of 3H-GABA uptake in the thyroid gland of the rat (1981)
    Springer
    Cell & tissue research 220 (1981), S. 873-879 
    Details
    ISSN: 1432-0878
    Keywords: γ-Aminobutyric acid (GABA) ; Autoradiography ; Thyroid gland ; Transport ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake of γ-aminobutyric acid (GABA) in the thyroid gland of the rat was studied autoradiographically following in vitro incubation. High-affinity GABA uptake was localized in follicle cells, whereas C cells (parafollicular cells) in general did not accumulate GABA by high-affinity transport. The follicle cells were also the main sites of low-affinity GABA uptake. Additionally, some nerve fibres were found to accumulate GABA. The predominant localization of GABA uptake in follicle cells is discussed in view of a presumed role of GABA in thyroid function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210468
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    Comparative studies of quinacrine-positive neurones in the myenteric plexus of stomach and intestine of guinea-pig, rabbit and rat (1981)
    Springer
    Cell & tissue research 221 (1981), S. 93-107 
    Details
    ISSN: 1432-0878
    Keywords: Quinacrine ; Myenteric plexus ; Non-adrenergic, non-cholinergic nerves ; Guinea-pig ; Rabbit ; Rat ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The number of quinacrine-fluorescent nerve cell bodies and the percentage of the ganglion area occupied by this fluorescence within stretch preparations of the myenteric plexus of the stomach and ileum of the guineapig, rabbit and rat were assessed. The number of quinacrine-positive cell bodies per cm2 of plexus varied between 1045 in the rabbit ileum to 2633 in the rat stomach, whilst the percentage of the ganglionic area occupied by fluorescence was approximately 10 %. The distribution of quinacrine-fluorescent nerve fibres and cell bodies in the myenteric plexus was compared to the distribution of nerves revealed by catecholamine fluorescence and by staining for acetylcholinesterase in the stomach and ileum of all three species. Quinacrine fluorescence appears to be selective for non-adrenergic, non-cholinergic nerves; the possibility that it binds to high levels of ATP is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216573
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    The effects of short-term fluoride ingestion on bone formation and resorption in the rat femur (1981)
    Springer
    Cell & tissue research 221 (1981), S. 421-430 
    Details
    ISSN: 1432-0878
    Keywords: Fluoride ; Bone ; Mineralization ; Resorption ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The femurs from rats given 120 ppm fluoride in their drinking water for 4 weeks were examined with histological, histochemical, and radiographic methods. Blood removed from the rats prior to sacrifice was analyzed for calcium, phosphorus, and alkaline phosphatase. Results of this study indicated that the ingestion of fluoride produced wide osteoid seams on the periosteal surface of the femoral diaphysis within 4 weeks. The increase in osteoid appeared to be due to an increase in the number of osteoid-producing cells (osteoblasts) along with a subsequent delay in the mineralization of this tissue. The metabolic activity of osteoblasts did not appear to be affected since the intracellular production of acid and alkaline phosphatase was not inhibited. However, due to the high concentration of fluoride ingested, abnormal collagen deposition and a change in bone mineral may have combined to cause a delay in osteoid mineralization. Mineralization was also delayed in the distal femoral epiphyseal plate resulting in an increase in the number of hypertrophied cells. Resorption of metaphyseal trabecular bone, presumably formed prior to fluoride administration, was increased causing a reduction in the amount of trabeculae extending into the shaft of the femur. Concurrent with these changes in bone, the serum levels of calcium, phosphorus, and alkaline phosphatase remained within normal ranges.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216745
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    Ultrastructure of elastic cartilage in the rat external ear (1981)
    Springer
    Cell & tissue research 218 (1981), S. 149-160 
    Details
    ISSN: 1432-0878
    Keywords: Elastic cartilage ; External ear ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of elastic cartilage in the external ear of the rat was investigated by transmission and scanning electron microscopy. The narrow subperichondrial, boundary zone contains predominantly ovoid cells rich in cell organelles: mitochondria, Golgi complex, granular endoplasmic reticulum and small (40–100 nm) vesicles. Scarce glycogen granules and bundles of 6–7 nm cytoplasmic filaments are also present. Deeper in the boundary zone, one or more cytoplasmic lipid droplets appear and cytofilaments become more abundant. Fully differentiated chondrocytes in the central zone of the cartilage plate resemble white adipose cells. They are globular and contain a single, large cytoplasmic lipid droplet. The cytoplasm is reduced to a thin peripheral rim; it contains a flattened nucleus, few cytoplasmic organelles and abundant, densely packed, cytoplasmic filaments. The intercellular matrix is very sparse. The pericellular ring consists of collagen fibrils about 20 nm in diameter and a proteoglycan cartilage matrix in the form of a “stellate reticulum”. The complex of these two structures appears in the scanning electron micrographs as a network of randomly oriented, ca 100 nm thick fibrils. Spaces between pericellular rings of matrix also contain thick elastic fibers or plates, apparently devoid of microfibrils. In scanning electron micrographs elastic fibers could be detected only in a few areas, in which they were not obscured by other constituents of the matrix. Immature forms of elastic fibers, oxytalan (pre-elastic) and elaunin fibers, were found in the perichondrial and boundary zones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210101
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    The hypothalamo-hypophysial system of hypophysectomized rats (1981)
    Springer
    Cell & tissue research 218 (1981), S. 607-622 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysectomy ; Median eminence ; Light and electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The median eminence (ME) of hypophysectomized rats was studied by means of light and electron microscopy. Paraldehyde-fuchsin (PAF)-positive material is seen in the external zone (EZ) of the ME 2–5 days after the operation. Its amount gradually increases especially in the caudal part of the ME during the following few days. Some PAF-positive fibers make contact with the subependymally located blood capillaries. In the most caudal region of the recessus infundibuli they penetrate into the third ventricle. PAF-positive material decreases markedly from the ME of rats two months after hypophysectomy and exposure to a 1% salt load. Fibers of types A1, A2 and B containing granules of 120–220 nm, 100–150 nm and 80–100 nm in diameter, respectively, are seen in the EZ of the ME in hypophysectomized rats, although almost exclusively A2- and B-type structures make contact with the primary portal capillaries in intact animals. All types of neurosecretory fibers establish contact with the subependymal nonfenestrated blood capillaries and penetrate the recessus infundibuli. Some neurosecretory terminals of different types make direct contact with the glandular cells of the pars tuberalis or are separated from them by a thin basal lamina. It is assumed that mainly neurosecretory fibers of types A2 and B are permanently connected with the primary portal capillaries in the EZ of the ME in intact mammals, while the overwhelming majority of fibers of A1-type shows ingrowth during the course of postoperative reparation. The possible physiological significance of the described changes is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210119
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    Immunocytochemical investigation of the subcommissural organ in the rat (1981)
    Springer
    Cell & tissue research 218 (1981), S. 659-662 
    Details
    ISSN: 1432-0878
    Keywords: Peptides ; Subcommissural organ ; Secretion ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The results of a preliminary immunocytochemical investigation on the subcommissural organ (SCO) in rats show that (1) Reissner's fiber (RF) or essential compounds of the RF are produced by the SCO, (2) the immunoreactive material is produced in the epithelial cells of the SCO as well as in the hypendymal cells, and (3) the immunoreactive material of the SCO belongs to a category of endogenous peptides to date not demonstrable immunocytochemically in other brain structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210122
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    p-Chlorophenylalanine-induced proliferation of the seminal vesicle epithelium (1981)
    Springer
    Cell & tissue research 219 (1981), S. 159-172 
    Details
    ISSN: 1432-0878
    Keywords: Seminal vesicles ; Proliferation ; Autoradiography ; Biochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intraperitoneal injection of p-chlorophenylalanine (pCPA) methylester (100 mg/kg body weight) results in an activation of the lysosomal system of the secretory cells in the rat seminal vesicle and an elevation of the activities of lysosomal enzymes within 15 min following the injection. Large autophagic vacuoles are formed, sequestering rough endoplasmic reticulum and part of the Golgi apparatus within 2 h. Shortly after the activation of the lysosomal system an elevation of both DNA and protein synthesis is measured biochemically. 6 h subsequent to the injection a wave of mitoses of the secretory cells begins, reaching a maximum 6 h later and then declining within 3 h. About 12 h following the injection a second rise in lysosomal activity begins, declining within 24 h. The entire sequence of lysosomal and proliferative activities is inhibited in antiandrogen-pretreated rats. Deduced from these findings the following hypothesis of growth regulation of the accessory sex glands is advanced: enhanced loss of intracellular material during autophagocytosis diminishes the intracellular concentration of a substance curtailing cell division below its effective threshold resulting in division of the secretory cells. The prerequisites of this mechanism are (i) a sufficient distributive capacity of the stroma for hormones (androgens) and metabolic precursors, and (ii) sufficient capacity of the basal cells for transporting the precursors to the secretory cells. Sloughing of the secretory cells separates them from these auxiliary structures (stroma and basal cells) and enables the basal cells to divide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210025
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    Monosodium glutamate-induced lesions in the rat cingulate cortex (1981)
    Springer
    Cell & tissue research 220 (1981), S. 239-250 
    Details
    ISSN: 1432-0878
    Keywords: Cingulate cortex ; Monosodium glutamate ; Neurotoxic amino acid ; Cell degeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brains of neonate albino rats were examined with the light and electron microscope following subcutaneous administration of monosodium glutamate (MSG). In addition to lesions in areas known to be vulnerable to glutamate, such as the arcuate nucleus of the hypothalamus, distinct areas of necrotic tissue were detected in the granular portion of the retrosplenial cingulate cortex. The affected cells display the cytological features characteristic of MSG-lesioned brain tissue, including vacuolization of the endoplasmic reticulum and clumping of chromatin. Numerous pyknotic nuclei can be detected as early as 3 h following treatment. The possible causes of the lesion, particularly the role that may be played by astrocytes, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210506
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    A comparison of neuropeptide immunocytochemistry in fluid-fixed and freeze-dried brains (1981)
    Springer
    Cell & tissue research 220 (1981), S. 223-230 
    Details
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Freeze-dried brain ; Fluid-fixed brain ; LHRH ; Somatostatin ; Neurophysin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical staining of luteinizing hormone-releasing hormone (LHRH), somatostatin, and neurophysin was compared in rat brains fixed with 1) formalin, 2) Bouin's solution, 3) freeze-dried (FD), or 4) freeze-dried + paraformaldehyde vapor perfused (FDV). The distribution of LHRH fibers was similar in all preparations; however, beads of granular reaction product often appeared finer and more numerous in the median eminence of FD- and FDV brains. Positively stained LHRH perikarya were not observed in any of the preparations. In contrast, somatostatin-immunoreactive perikarya were present in the fluid-fixed and FD brains, although few were observed in FDV brains. Somatostatin-immunoreactive fibers were present in all preparations, but appeared most numerous in the median eminence of FD brains. Staining of neurophysin-containing perikarya and fibers was similar in all preparations. These observations suggest that the FD brain can provide a suitable tissue substrate for immunocytochemistry, demonstrating staining comparable to or surpassing that of more conventional preparations. However, staining of antigens in FD brain was not uniformly successful and may depend on stereochemical characteristics of each antigen as well as properties of the primary antisera used in the staining procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210504
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  • 243
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    Polare Substituenteneffekte bei der Addition von Alkyl-Radikalen an Alkene (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2138-2145 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polar Substituent Effects in Additions of Alkyl radicals to AlkenesReduction of cyclohexylmercuric salts (7) with NaBH4 yields cyclohexyl radicals (8). Their rel rates of addition to substituted styrenes 4, acrylic esters 5 and acrylonitriles 6 have been measured. Comparison with Hammet σ-values show, that substituents at the non attacked vinylic carbon atom show polar effects mainly (Table 1). The effect of a substituent variation increases with increase of the reactivity of the alkenes (Table 2). Mesomeric and steric effects play only a minor role.
    Notes: Die Reduktion von Cyclohexylquecksilbersalzen (7) mit NaBH4 liefert Cyclohexyl-Radikale (8), deren rel. Geschwindigkeitskonstanten der Addition an substituierte Styrole 4, Acrylsäureester 5 und Acrylonitrile 6 gemessen wurden. Der Vergleich mit Hammettschen σ-Werten zeigt, daß die Substituenten am nicht angegriffenen vinylischen Kohlenstoffatom im wesentlichen polare Effekte auf die Additionsgeschwindigkeit ausüben (s. Tab. 1). Der Substituenteneinfluß nimmt dabei mit steigender Reaktivität der Alkene zu (s. Tab. 2). Mesomere und sterische Effekte spielen nur eine untergeordnete Rolle.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140614
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    N-Chlorimine, I. Oxidative Decarboxylierung von Dispirochinoxalinaminosäuren (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2146-2157 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Chloroimines, I. Oxidative Decarboxylation of Dispiroquinoxaline Amino AcidsStarting with the trispiro dimer 1a, the quinoxaline amino acids 4 are accessible in two steps. Instead of the expected ketone 8, the oxidative decarboxylation of 4b with lead tetraacetate produces the lactame 5, the nitrile 6, and the N-chloroimine 7. By degradation in the presence of pyridine, 7 can be prepared exclusively. The hydrolysis of 7 leads to the desired ketone 8. Besides the known compounds 5, 6, and 8, the Beckmann rearrangement of 7 results in the formation of the chloroketone 11. The degradation of 4b with NBS leads to the stable N-bromoimine 9.
    Notes: Ausgehend vom Trispirodimeren 1a sind die Chinoxalinaminosäuren 4 in zwei Reaktionsschritten zugänglich. Die oxidative Decarboxylierung von 4b mit Bleitetraacetat ergibt anstelle des erwarteten Ketons 8 das Lactam 5, das Nitril 6 und das N-Chlorimin 7. Durch Abbau in Gegenwart von Pyridin kann 7 gezielt dargestellt werden. Die Hydrolyse von 7 führt zum gesuchten Keton 8; die Beckmann-Umlagerung ergibt neben den bereits bekannten Verbindungen 5, 6 und 8 zusätzlich das Chlorketon 11. Beim Abbau von 4b mit NBS wird in Analogie zum Bleitetraacetat-Abbau das stabile N-Bromimin 9 erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140615
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    Photolytische Decarbonylierung von Anhydrozucker-Ulosen zur Synthese von 1,5-Anhydro-β-D-lyxo- und -ribofuranosen sowie 2,6-Anhydro-β-D-psicofuranosen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 891-908 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Decarbonylation of Anhydro Sugar Uloses and Syntheses of 1,5-Anhydro-β-D-lyxo-ribofuranoses, and 2,6-Anhydro-β-D-psicofuranosesBy photochemical decarbonylation of the 1,6-anhydro-2- (1) and -4-uloses 3 with D-lyxo configuration stereoselective ring contractions yield the 1,5-anhydro-β-D-lyxofuranose derivative 2. Via corresponding transformation the benzylidene derivative 9 is obtained, by hydrogenolysis of which the unblocked 1,5-anhydro-β-D-lyxofuranose (10a) is prepared. Opening of the benzylidene ring in 9 by N-bromosuccinimide proceeds stereo-and regioselectively to give the 3-bromo-3-deoxy-D-arabino compound 7, reductive dehalogenation of which yields the derivative 8. - Similarly, the 1,6-anhydro-2- (11) and -4- uloses (13) with D-ribo configuration stereoselectively lead to the formation of the 1,5-anhydro-β-D-ribofuranose compound 12. By benzylidenation of altrosan (14) both the exo- (16a) and the endo-derivative (17a) are obtained, separated, and separately oxidized to the 2-uloses with exo-(19) and endo-configuration 20. Their photochemical decarbonylation is associated with a photoisomerisation at the benzylidene carbon atom thus giving rise to the formation of both exo-22 and endo 23 which are separated. An alternative synthesis of exo-22 and endo-23 starting with gulosan (15) proceed via the benzylidene derivative 18a and the 4-ulose 21. Hydrogenolysis of exo-22 and endo-23 gives 1,5-anhydro-β-D-ribofuranose (24a).
    Notes: Durch photolytische Decarbonylierung der D-lyxo-konfigurierten 1,6-Anhydro-2-(1) und -4-ulosen (3) wird jeweils stereoselektiv das ringkontrahierte 1,5-Anhydro-β-D-lyxofuranose-Derivat 2 gewonnen. Entsprechend wird die Benzyliden-Verbindung 9 dargestellt und durch Hydrogenolyse daraus die freie 1,5-Anhydro-β-D-lyxofuranose (10a) zugänglich. Die bromierende Benzylidenringöffnung an 9 verläuft stereo-und regioselektiv zum 3-Brom-3-desoxy-D-arabino-Derivat 7, das reduktiv zu 8 dehalogeniert wird. - In gleicher Weise werden die D-ribo-konfigurierten 1,6-Anhydro-2- (11) bzw. -4-ulosen (13) photolytisch stereoselektiv zum 1,5-Anhydro-β-D-ribo-furanose-Derivat 12 decarbonyliert. Durch Benzylidenierung von Altrosan (14) lassen sich das exo- (16a) und das endo-konfigurierte Derivat 17a getrennt erhalten und zu den 2-Ulosen exo-19 und endo-20 oxidieren. Deren Photolyse verläuft jeweils unter Decarbonylierung sowie Photoisomerisierung am Acetal-C-Atom zum Gemisch der exo-(22) und endo-Derivate (23), die getrennt werden. Alternativ sind exo-22 und endo-23 auf einem vergleichbaren Syntheseweg aus Gulosan (15) über die Benzylidenverbindung 18a und die 4-Ulose 21 erhältlich. Ihre Hydrogenolyse gibt freie 1,5-Anhydro-β-D-ribofuranose (24a). -Mit der decarbonylierenden Photolyse der isopropyliden-bzw. benzyliden-geschützten 2,7-Anhydro-β-D-ribo-heptulopyranos-3-ulosen 26 bzw. 33 werden Synthesewege zu den 2,6-Anhydro-β-D-psicofuranose-Derivaten 27 bzw. 32 vorgestellt. Aus den entsprechenden 3-Ulose-Vorstufen 35 und 38 sowie 39 ist die Herstellung der Derivate von 2,6-Anhydro-1-desoxy-β-D-psicofuranose 36 und 41 sowie 42 möglich.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140307
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    Eisen-und Cobalt-Cluster nach der Propen-Eliminierungs-Methode. Die Cluster CO4(CO)10[P(CH3)2(CH2CHCH2)]2 und Fe2Co(CO)8[μ-SCH3]2[μ-P(CH3)2] (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1111-1123 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iron and Cobalt Clusters by the Propene Elimination Method: The Clusters Co4(CO)10[P(CH3)2(CH2CHCH2)] and Fe2Co(CO)8[μ-SCH3]2 [μ-P(CH3)2]The dinuclear dimethylphosphane complexes (CO)3 Fe(μ2-ERX)2—Fe(CO)2P(CH3)2H (2: ERX = P(CH3)2 3: ERX = SCH3) were synthesized. They do not react with η3-(C3H5)Co(CO)3 (4) to the expected ERX-bridged complexes with sequential metal-metal bonds. Instead, the title complexes 12 and 18 were formed. The structures of the two complexes were determined crystallographically and NMR-spectroscopically. In the case of 18 the the two possible arrangements of the metal atoms are discussed.
    Notes: Die zweikernigen Dimethylphosphan-Komplexe (CO)3Fe(μ2—ERX)2-Fe(CO)2P(CH3)2H (2: ERX = P(CH3)2, 3: ERX = SCH3) wurden dargestellt. Sie reagieren mit η3- (C3H5)Co(CO)3 (4) nicht wie erhofft zu basenverbrückten Komplexen mit sequentiellen Metall-Metall-Bindungen, sondern zu den beiden Titelkomplexen 12 und 18. Die Strukturen der beiden Komplexe wurden kristallographisch und NMR-spektroskopisch aufgeklärt. Für 18 werden zwei alternative Zuordnungen der Metallatome diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140328
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    Fluorierungen von Uracil und 3-O-Acetyldigitoxigenin (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1176-1179 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorinations of Uracil and 3-O-AcetyldigitoxigeninFluorination of uracil (1) in acetic anhydride/5% glacial acetic acid gives 6-acetoxy-5-fluoro-5,6. dihydrouracil (2). Using OF2 instead of F2 leads analogously to 5,5-difluorobarbituric acid. A selective OH/F exchange is achieved on 3-O-acetyldigitoxigenin (4) with SF4 in the presence of dry KF at 20°C producing 3-O-acetyl-14-deoxy-14-fluorodigitoxigenin 5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140334
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  • 248
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    Kernresonanzspektroskopische Untersuchungen an Borverbindungen, XIX. 13 C-NMR-Studien an Monoaminoboranen und Borazinen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1150-1156 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies of Boron Compounds, XIX. 13C NMR Studies on Monoaminoboranes and BorazinesChemical shifts δ13C of aminoboranes R2BNR′2 1 and X2BNR′2 2 as well as of borazines (RBNR′)3 3 and (XBNR′)3 4 (X = F, Cl, Br, I, OR, SR, NR2) can be explained by the action of a γ-effect exerted by R and X on the shielding of 13 C(BC) and 13C(NC). Analogies exist with similar effects in alkenes, imonium slats and benzene derivatives. - Heteronuclear 13C{1H, 11B} triple resonance experiments permit the observation of sharp 13C(BC) resonance signals.
    Notes: Chemische Verschiebungen δ13C von Aminoboranen R2BNR′2 1 und X2BNR2′ 2 sowie von Borazinen (RBNR′)3 3 und (XBNR′)3 4 (X = F, Cl, Br, I, OR, SR, NR2) könen mit der Wirkung eines γ-Effektes von R und X auf δ13C(BC) und γ13C(NC) erklärt werden. Es bestehen Analogien zu Alkenen, Imoniumsalzen und Benzolderivaten. - Heteronucleare 13C{1H, 11B} Tripelresonanz-experimente erlauben die Betrachtung scharfer 13C(BC)-Resonanzsignale.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140332
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  • 249
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    Über die Darstellung von Bis(trimethylsiloxy)germanium(II) und -blei(II) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1180-1181 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Bis(trimethylsiloxy)germanium(II) and -lead(II)Bis(trimethylsiloxy)germanium(II) (1) is obtained in more than 80% yield from the germanium dichloride-dioxane complex with sodium trimethylsilanolate, bis(trimethylsiloxy)lead (II) (2) is formed in more than 70% yield from yellow PbO with trimethylsilanole. Both compounds are fairly soluble in all inert organic solvents, they are associated by bridging siloxy groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140335
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  • 250
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    N-Acylketenimine (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1976-1979 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-AcylketeniminesThe title compounds 3 are prepared via Wittig reaction from disubstituted methylenephosphoranes 1 and acyl isocyanates 2. compounds 3 react with aromatic amines, carbodiimides, and isonitriles to afford N-Acyl-enamines 8, alkyliden-oxadiazinimines 9, or alkyliden-Oxazolimines 10, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140537
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  • 251
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    Über Thioacyl-isocyanate, XIV1) Reaktion mit 2-Bromethanol zu Oxazolon-und 1,5,3-Oxathiazepinon-Derivaten (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1972-1975 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thioacyl Isocyanates, XIV1) Reaction with β-Bromethanol to Derivatives of Oxazolones and 1,5,3-OxathiazepinonesThioacyl isocyanates 1, R = Alkyl and Aryl, react with 2-bromethanol via urethanes 2 normally to N-thioacyloxazolidinones 4, in case of R = tert-butyl to the 1,5,3-oxathiazepion 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140536
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  • 252
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    Beiträge zur Chemie des Bors, 118. Struktur und Dynamik von Hexamethylborazin-Aluminiumbromid (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2723-2730 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron 118. Structure and Dynamics of Hexamethylborazine-Aluminium TribromideAluminium tribromide in its 1:1 adduct with hexamethylborazine coordinates with one nitrogen atom. This results in a loss of the planarity of the borazine ring system, and the BN bond lengths vary now from 139 to 154 pm as shown from an X-ray crystal structure determination of the monoclinic adduct (Rw = 0.076). The ring conformation is additionally influenced by weak intramolecular and intermolecular Br-B interactions. The adduct shows fluctional behaviour in solution at temperatures higher than 276 K.
    Notes: Aluminiumbromid koordiniert in seinem 1: 1-Addukt mit Hexamethylborazin über ein N-Atom Der Borazin-Ring verliert dadurch seine Planarität, seine BN-Abstände variieren zwischen 139 und 154 pm, wie aus der Röntgenstrukturanalyse des monoklin kristallisierenden Addukts her-vorgeht (Rw = 0.076). Die Ringkonformation wird durch schwache intramolekulare und intermolekulare Br-B-Wechselwirkungen geprägt. In Lösung zeigt das Addukt fluktuierendes Verhalten oberhalb von 276k.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140806
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  • 253
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    Dispirocyclobutane und Propellane aus 1,2-Bisenollactonen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1983-1990 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dispirocyclobutanes and Propellanes from 1,2-BisenollactonesElectronically excited biphthalidylidene (1) and isocoumarino-isocoumarin (5) are trapped by electron-Poor stilbenes and by 1,3-dienes to give the dispirocyclobutanes 3, 8, 9, 11, 12 and the heterocyclic [4.4.2]propellanes 6 and 14 resp. The unusual tetraspirocyclobutane 4 is formed upon photodimerization of 1 as a by-product. The structures of the products have been established primarily by high-field, 1H-NMR spectroscopy and in part by chemical transformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140539
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    Berichtigung (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1991-1991 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140540
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  • 255
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    Reaktionen des (+)-Thujons und (-)-Isothujons mit Formaldehyd (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1993-2000 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of (+)-Thujone and (-)-Isothujone with Formaldehyde(+)-Thujone and (-)-isothujone react with formaldehyde to give 4β-(hydroxymethyl)thujone (1) and the 2-methylene derivatives 6 and 7. Oxidation of 1 gives thujone-4β-carboxylic acid (2) which decarboxylates to (+)-thujone. 1 is reduced to the isomeric 4β-(hydroxymethyl)-(3a, 3b) and 4-methylthujanols (4a, 4b). 3-Methylthujanol is oxidized to 4-methylthujone (5).
    Notes: (+)-Thujon und (-)-Isothujon reagieren mit Formaldehyd zu 4β-(Hydroxymethyl)thujon (1) und zu den 2-Methylenderivaten 6 und 7. Oxidation von 1 ergibt Thujon-4β-carbonsäure (2), die zu (+)-Thujon decarboxyliert wird. Reduktion von 1 führt zu den isomeren 4β-(Hydroxymethyl)-(3a, 3b) und zu 4-Methylthujanolen (4a, 4b). Aus 4-Methylthujanol wird durch Oxidation 4-Methylthujon (5) erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140602
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  • 256
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    Offenkettige und cyclische Bis-phosphorane aus α,ω-Dinitrilen, Diisobutylaluminiumhydrid und Methylentriphenylphosphoran (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2261-2271 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Open-chain and Cyclic Bis-phosphoranes from α,ω-Dinitriles, Diisobutylaluminium Hydride, and MethylenetriphenylphosphoraneThe reaction of subero-, azelao-, and sebaconitrile (4, n = 6,7, and 8) with diisobutylaluminium hydride (to give 5) and subsequently with methylenetriphenylphosphorane leads to the openchain bis-phosphoranes 8a-c, which have been characterized by the Wittig reaction. The same reaction sequence applied to adiponitrile produces the cyclic bis-phosphorane 9a. The previously unknown hydrocarbon 1,3,9,11-cyclohexadecatetraene (12) has been prepared from 8a and adipoaldehyde.
    Notes: Die Reaktion von Subero-, Azelao- bzw. Sebaconitril (4, n = 6,7 bzw. 8) mit Diisobutylaluminiumhydrid (zu 5) und anschließend mit Methylentriphenylphosphoran führt zu den offenkettigen Bis-phosphoranen 8a-c, die durch die Wittig-Reaktion charakterisiert wurden. Im Falle des Adiponitrils führt die gleiche Reaktionsfolge zu einem cyclischen Bis-phosphoran 9a. Aus 8a und Adipoaldehyd wurde der bisher unbekannte Kohlenwasserstoff 1,3,9,11-Cyclohexadecatetraen (12) synthetisiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140622
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    Silaborazine und fluorborylsubstituierte Cyclotrisilazane (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2287-2292 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Silaborazines and Fluoroboryl-substituted Cyclotrisilazanes2,2,4,4,6,6-Hexamethylcyclotrisilazanes and their lithium salts (2, 1b, 4) react with BF3-etherate to give silaborazines (8, 9, 13, 15) A BF-bridged cyclotrisilazane (10) could be isolated. Substitution at the ring occurs in the reaction of 2,2,4,4,6,6-hexamethyl-1,3-bis(trimethylsilyl)cyclotrisilazane (5) with BF3-etherate and of 1-lithio-2,2,4,4,6,6-hexamethylcyclotrisilazane (1a) with [bis(trimethylsilyl)amino]difluoroborane.
    Notes: 2,2,4,4,6,6-Hexamethylcyclotrisilazane und deren Lithiumsalze (2, 1b, 4) reagieren mit BF3- Etherat zu Silaborazinen (8, 9, 13, 15). Ein BF-verknüpftes Cyclotrisilazane (10) konnte isoliert werden. Substitution am Ring erfolgt in den Reaktionen von 2,2,4,4,6,6-Hexamethyl-1,3-bis(trimethylsilyl)cyclotrisilazan (5) mit BF3-Etherat sowie von 1-Lithio-2,2,4,4,6,6-hexamethylcyclotrisilazan (1a) mit [Bis(trimethylsilyl)amino]difluorboran.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140624
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    Cyclisch gekreuzt-konjugierte Bindungssysteme, 361) Fidecene Synthesen, Cycloadditionen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1656-1678 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Cross-Conjugated Bond Systems, 361) Fidecenes Syntheses, Cycloaddition ReactionsFidecenes, which in the 5-membered ring are doubly annelated (9/10) or fourfold phenyl-(18) and twofold tert-butyl-substituted (21), as well as the symmetrical (3) and unsymmetrical (25) parent compounds, have been synthesized. the stability of these typically “fulvalenoidal” olefines is determined by the degree of substitution - the derivatives (9, 10, 18, 21) are thus obtained crystalline, the basic frameworks (3, 25) only in dilute solution. 10 reacts via a valence tautomer (31) with maleic anhydride (140°C) to give the [4 + 2]-adduct 32. Addition of dimethyl acetylenedicarb-oxylate (80°C) occurs in the fulvene portion ([4 + 2]) giving 33/34. Reaction with tetracyanoethylene (20°C) leads regio- and perispecifically to a 1:1 adduct (37), which results, at least formally, from a “symmetry-allowed” [π16s + π2s]-cycloaddition followed by a suprafacial [1,9]-H shift. The structure of 37 was verified by an X-ray structure analysis.
    Notes: Die im Fünfring zweifach anellierten (9/10), vierfach phenyl- (18) und zweifach tert-butyl-substituierten (21) Fidecene sowie das symmetrische (3) und unsymmetrische Grundgerüst (25) wurden synthetisiert. Die Beständigkeit dieser typisch “fulvalenoiden”, Olefine wird durch den Substitutionsgrad bestimmt, so daß die Derivate (9, 10, 18, 21) kristallisiert, die Grundgerüste (3, 25) nur in verdünnter Lösung gewonnen wurden. 10 setzt sich über ein Valenztautomeres (31) mit Maleinsäureanhydrid (140°C) zum [4+2]-Addukt 32 um. 21. addiert Acetylendicarbonsäure dimethylester (80°C) im Fulventeil ([4+2] zu 33/34. Mit Tetracyanethylen (20°C) wird regio und perispezifisch ein 1:1-Addukt (37) gebildet, welches - zumindest formal - aus einer, “symmetrieerlaubten” [π16s + π2s]-Cycloaddition mit anschließender suprafacialer [1,9]-Wasserstoffverschiebung resultiert. Die Konstitution 37 ist durch eine Röntgenstrukturanalyse gesichert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140509
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    Heterocyclische 8 π-Systeme, 141) Erzeugung und Reaktionen von Cyaninfarbstoff-Leukoverbindungen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1723-1736 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic 8π-Systems, 141) Generation and Reactions of Cyanine Dye Leuko compoundsThe symmetric cyanine dyes 2a-c, 3a, 4a, and 5a were transformed into the leuko compounds 7-10, 12, and 14. Deprotonation of 7 and 8 with lithium diisopropylamide led to the corresponding cyanine dye anions, which yielded derivatives of the leuko compounds (25 - 30 and 34, 35, respectively) with electrophiles. The cyanine dyes 2a, 3a and the leuko compounds 7, 8 delivered with lithium tetracyano-p-quinodimethan anion (LiTCNQ) and tetracyano-p-quinodimethan (TCNQ) simple (36, 37), and complex salts (38, 39), respectively. 39 displayed interesting conductivity.
    Notes: Aus den symmetrischen Cyaninfarbstoffen 2a-c, 3a,4a und 5a wurden die Leukoverbindungen 7-10,12 und 14 hergestellt. Durch Deprotonierung von 7 und 8 mit Lithium-diisopropylamid wurden die entsprechenden Cyaninfarbstoff-Anionen erzeugt, welche mit Elektrophilen zu Derivaten der Leukoverbindungen (25-30 bzw. 34, 35) führten. Aus den Cyaninfarbstoffen 2a, 3a und den Leukoverbindungen 7, 8 wurden mit Lithium-[tetracyan-p-chinodimethan-Anion] (LiTCNQ) bzw. Tetracyan-p-chinodimethan (TCNQ) einfache (36, 37) und komplexe Salze (38, 39) erhalten. 39 zeigte interessante Leitfähigkeitseigenschaften.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140512
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    Cyclisch gekreuzt-konjugierte Bindungssysteme, 381) Vierzehn-Elektronen-Elektrocyclisierung des vinylogen Sesquifulvalens - Phenazulen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1697-1722 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Cross-Conjugated Bond Systems, 381) Fourteen Electron Electrocyclisation of the Vinylogous Sesquifulvalene - PhenazuleneThe vinylogous sesquifulvalene 1 thermally undergoes 14-electron electrocyclisation with ease (Ea = 100 ± 2kj·mol-1, log A = 12.0) and perispecifically. Due to the steric constraints imposed by the system it takes place - almost certainly exclusively - in the “symmetry-forbidden”, conrotatory sense to give trans- 10a, 10b-dihydrophenazulene 2a. This is rapidly isomerized into the benzenoid 1,8- and 3,8- dihydrocyclohept[e]indenes 12/15 and is therefore not directly detectable. The trans-stereochemistry in 2a is verified by x-ray crystal analysis of its 1:1-adduct with dimethyl acetylenedicarboxylate (20). The benzylidenecyclohept[e]indenes 28a-c(obtainable from 12/15) could not be isomerised prototropically to the benzylphenazulenes 30a-c. Treatment of the cation 31 (generated from 28a) with nucleophiles also fails to produce phenazulene derivatives (34). The phenazulenium salts 38/39 are, depending on the counteranion, obtainable from 12 (15) in solution (BF-4, ClO-4) or crystalline (SbCl-6, 1/2 PtCl2-6 EE). From the BF-4 salt a deep-blue compound is generated which is stable below -60°C and in the presence of a large excess of DBN, but polymerises above 0°C or in the presence of SiO2 or Al2O3 (-60°C). It is concluded, that this blue species is phenazulene (3).
    Notes: Das vinyloge Sesquifulvalen 1 geht thermisch leicht (Ea = 100 ± 2kJ. Mol-1, log A = 12.0) und perispezifisch die 14-Elektronen-Elektrocyclisierung ein. Unter dem Zwang der Sterischen Verhältnisse erfolgt diese - sehr wahrscheinlich ausschließlich - im “symmetrieverbotenen”, konrotatorischen Sinn zum trans-10a, 10b-Dihydrophenazulen 2a. Dieses ist wegen der raschen Isomerisierung in die benzoiden 1,8- und 3,8-Dihydrocyclohept[e]indene 12/15 direkt nicht nachweisbar. Die trans-Stereochemie in 2a wird durch Röntgenstrukturanalyse seines 1:1-Addukts mit Acetylendicarbonsäure-dimethylester (20) bewiesen. Die aus 12/15 hergestellten Benzyliden-cyclohept[e]indene 28a-c konnten prototrop nicht zu den Benzylphenazulenen 30a - c isomerisiert werden. Phenazulen-Derivate (34) entstehen auch nicht bei der Umsetzung des aus 28a gewonnenen Kations 31 mit Nucleophilen. Die Phenazulenium-Salze 38/39 sind je nach Gegenion in Lösung (BF-4, CIO-4) bzw. kristallisiert aus 12 (15) herstellbar (SbCl-6, 1/2PtCl2-6). Aus dem BF-4-Salz wird eine bei -60°C und großem DBN-Überschuß beständige, tiefblaue Verbindung freigesetzt, die oberhalb 0°C bzw. im Kontakt mit SiO2O3(-60°C) rasch polymerisiert. Es wird argumentiert, daß es sich hierbei um Phenazulen (3) handelt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140511
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    Die Synthese von α-Arylhydrazono-2,5-dihydro-2-methyl-2-thiazolessigsäureestern und deren Umlagerung unter elektrophilem Angriff (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2336-2347 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of α-Arylhydrazono-2,5-dihydro-2-methyl-2-thiazoleacetic Esters and its Rearrangement by Electrophilic AttackTwo pathways to 3-amino-2-arylazo-2-butenoic esters 6 starting from acetoacetic esters have been investigated. The esters 6 can be converted with oligometic α-mercaptoaldehydes to α-arylhydrazono-2,5,-dihydro-2-methyl-2-thiazoleacetic esters 2 and 9. Acylation of the compounds 2 occurs at sulfur with concomitant opening of the ring system to give 3-[(Z)-2-(acylthio)vinylimino]-a-(arylhydrazono)butanoic esters (17).
    Notes: Zwei Wege zu 3-Amino-2-arylazo-2-butensäureestern 6 aus Acetessigsäureestern werden untersucht. Aus den Verbindungen 6 sind mit Hilfe von oligomeren α-Mercaptoaldehyden die α-Arylhydrazono-2,5-dihydro-2-methyl-2-thiazolessigsäureester 2 und 9 zugänglich. Die Verbindungen 2 werden am Schwefel acetyliert unter Ringöffnung zu 3-[(Z)-2-(Acylthio)vinylimino]-2-(arylhydrazono)buttersäureestern (17).
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140629
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    Glycosylhydrazine, 5. Aufbauende Synthese der 5-Säureamid-Derivate von Pyrazol-, Pyrazolo[3,4-d]pyrimidin- und 1H-1,2,4-Triazol-nucleosiden (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2834-2843 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosylhydrazines, 5. Synthesis of pyrazole-, Pyrazolo[3,4-d]pyrimidine-, and 1H-1,2,4-Triazol-Nucleoside 5′-amide Derivatives via Riburonamide HydrazonesIn a single step reaction the 3,5-dimethylpyrazole nucleoside-5′-amides 6a,c, the functionally substituted pyrazole nucleoside-5′-amides 9a and 10b, and the 1H-1,2,4-triazol-nucleoside-5′-amide 18 were obtained regio- and stereoselectively from the riburonamide hydrazones 4a-c.9a and 10b were transformed into the unprotected pyrazolo[3,4-d]pyrimidine nucleoside-5-amide 14a and 15b, derivatives of allopurinol riboside. likewise the ethylamide 20 of virazole-5′-acid was synthesized from 18.
    Notes: Aus den Riburonamid-hydrazonen 4a-c wurden in einer Eintopfreaktion regio- und stereoselektiv die 5′-Säureamid-Derivate des 3,5-Dimethylpyrazol-nucleosids 6a,c, der funktionell substituierten Pyrazol-nucleoside 9a) und 10n) und des 1H-1,2,4-Triazole-nucleosids 18 direkt aufgebaut. Als Allopurinolribosid-Derivate wurden aus 9a und 10b die ungeschützten pyrazolo[3,4-d]pyrimidin-nucleosid-5′-säureamide 14a und 15b hergestellt. Entsprechend wurde aus 18 das Ethylamid 20, der Virazol-5′-säure erhalten.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140815
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    Das Allopolarisierungsprinzip und seine Anwendungen, IV. Substituenteneffekte bei der Methylierung von Enolat-Anionen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2866-2883 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Allopolarization principle and its Applications, IV1) Substituent Effects in the Methylation of Enolate AnionsThe ratio of O- and C- methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethyl ketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents. In some case the influence of solvents, concentration and temperature has also been studied.
    Notes: Das Verhältnis von O- zu C-methylierten Produkten bei der Umsetzung der Natriumsalze von Acetophenonen 1, Propiophenonen 3, Phenylacetonen 5, β-Dicarbonylverbindungen 12, α-Cyancarbonylverbindungen 13, Acetaldehyd, Propionaldehyd und Diethylketon mit Dimethylsulfat, Methyliodid und Trimethylphosphat in Hexamethylphosphorsäuretriamid wurde im Hinblick auf der Substituenteneffekt bestimmt. In einigen Fällen wurde auch den Einfluß des Lösungsmittels, der Konzentration und der Temperatur untersucht.
    Additional Material: 11 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140818
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    Das Allopolarisierungsprinzip und seine Anwendungen, V. 13C—NMR-Spektren von Enolaten und verwandten Carbanionen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2884-2897 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Allopolarization principle and its Applications, V1 13C NMR Spectra of Enolates and Related CarbanionsThe 13C NMR Spectra of the sodium salts of p-substituted propiophenones and phenylacetones, of benzylcarbonyl compounds, acetonitrile derivatives, and β-dicarbonyl compounds reveal the influence of substituents on the charge distributions in enolates and related carbanions. Increments for substituents on the methanide-C are evaluated (Table 12.). The charge densities on C-α of benzyl anions can be derived from the C-p13C NMR chemical shift. The special effect of cyano groups in carbanions is discussed.
    Notes: Die 13C—NMR-Spektren der Na-Salze von p-substituierten Propiophenonen un Phenylacetonen, von Benzylcarbonylverbindungen, Acetonitrilderivaten und β-Dicarbonylverbindungen zeigen den Einfluß von Substituenten auf die Ladungsverteilung in Enolaten und verwandten Carbanionen. Inkremente für Substituenten am Methanid-C werden ermittelt (Tab.12). Die Ladungsdichten an C-α von Benzyl-Anionen lassen sich aus den C-p13C—NMR-Signalen ableiten. Der besondere Effekt von Cyangruppen in Carbanionen wird diskutiert.
    Additional Material: 14 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140819
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    Die quantitative Beschreibung der Lösungsmittelpolarität binärer Gemische unter Berücksichtigung verschiedener Polaritätsskalen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2907-2913 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Quantitative Description of Polarity of Binary solvent Mixtures Using Different Polarity ScalesThe solvent polarities of 12 binary mixtures have been examined using 6 polarity scales as a function of their composition. They are quantitatively described by a simple, closed form, two-parameter equation which can explain e.g. deviations from linear correlations of polarity scales for mixtures.
    Notes: Die Lösungsmittelpolaritäten von 12 binären Gemischen sind als Funktion ihrer Zusammensetzung unter Berücksichtigung von 6 Polaritätsskalen untersucht worden. Sie erfüllen alle quantitativ eine Zwei-Parameter-Gleichung, mit deren Hilfe u.a. Abweichungen von der linearen Korrelation der Polaritätsskalen bei Gemischen erklärt werden können.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140821
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  • 266
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    Wittig-Reaktionen mit Cyanhydrinen sowie Redoxreaktion des 4-Nitromandelsäurenitrils (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2914-2920 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wittig Reactions of Cyanohydrines and Redox Reaction of 4-NitromandelonitrileSubstitued mandelonitriles 5 (R1 = H, OCH3, NO2) react in the presence of sodium tert- butoxide as a base like the corresponding aldehydes with substituted benzylidenetriphenylphosphoranes via the Wittig reaction to yield 4,4′-disubstituted stilbenes 8, for which the (E)/(Z) stereoisomer ratios are given. Our results refer to a reaction with a preceding cyanohydrine-aldehyde equilibrium. 4-Nitromandelonitrile (5a) forms in a basic methanolic solution via a redox reaction a mixture of dimethyl 4,4′-azoxybenzenedicarboxylate (11) and methyl 4-nitrobenzoate (12).
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140822
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    Reaktionen der Methylencyclopropane, VI1) Palladium(0)-katalysierte [2σ + 2π]-Cycloadditionen des 1-Methylen-2-vinylcyclopropans (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3325-3335 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Methylenecyclopropanes, VI1) Palladium (0)-catalysed [2σ + 2 π] Cycloadditions of 1-Methylene-2-vinylcyclopropane1-Methylene-2-vinylcyclopropane (1) is cyclodimerised at palladium (0)/triisopropylphosphane catalysts to give th carbocycles 3-5, which in certain cases are obtained as Z/E-6 and 7. The thermal rearrangment of 1 to 3-Cyclopentene (2) competes with these catalytic reactions. Allylidenecyclopropane (9), which was synthesized for reasons of comparison, does not undergo cyclo- ro codimerisation at the palladium (0) catalysts used here.
    Notes: 1-Methylen-2-vinylcyclopropan (1) wird an Palladium (0)/Triisopropylphosphan-Katalysatoren zu den Carbocyclen 3-5 cyclodimerisiert, die z. T. als Z/E-Isomere auftreten. Mit Norbornen erfolgt Codimerisierung zu den Tricyclen Z/E-6 und 7. In Konkurrenz zu diesen katalytischen Reaktionen lagert sich 1 rein thermisch in 3-Methylen-1-cyclopenten (2) um. Das zu Vergleichszwecken synthetisierte Allylidencyclopropan (9) geht an den verwendeten Palladium (0)-Katalysatoren weder Cyclo- noch Codimerisierung ein.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811141013
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    Sterische Effekte bei endo, exo-Tetracyclo[6.2.1.13,6.02,7]-dodecanen: Einfluß von 4-Substituenten auf die Solvolyse der 11-epimeren Sulfonate1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3336-3348 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Steric Effects in endo, exo-tetracyclo [6.2.1.1.3,602,7]dodecanes: Influence of 4-Substituents on the Solvolysis of Epimeric 11-Sulfonates1)By stereoselective additions of 11-anti-acetoxy-endo,exo-tetracyclo[6.2.1.13,6.02,7]dodec-4-ene (12a) compounds 6, 13-18 have been Prepared. Olefin 19, obtained by Wittig reaction from 17, was hydrogenated yielding methyl compound 9b. Reduction of the keto group of 16 gives the 11-syn alkohol 11a. Rates of solvolysis of sulfonates 5b,c, 6b, 7b, 8b, 9c, 10c, and 11b have been determined in 60% acetone. Rates of tosylates 2b-anti, 5e, and 9d in acetic acid can be correlated by the calculated difference of strain energy (hydrocarbon-cation). syn-Sulfonates 8b and 11b react ca. 103 times faster than the anti-isomers 5c and 9c. - Isomerisation of “inside” -epimers 26 and 29 to the “outside”-compounds 28 and 31 cannot be achieved due to the outside attack.
    Notes: Durch stereoselektive Additionsreaktionen an die Doppelbindung von 11-anti-Acetoxy-endo,exo-tetracyclo [6.2.1.13,6.02,7]dodec-4-en (12a) wurden die Verbindungen 6, 13-18 hergestellt. Das Olefin 19 wird durch Wittig-Reaktion aus dem Keton 17 erhalten, es läßt sich katalytisch zur Methylverbindung 9b hydrieren. Reduktion der Ketogruppe in 16 mit LiAlH4 ergibt die 11-syn-Verbindung 11a. - Die Solvolysegeschwindigkeit der Sulfonate 5b,c, 6b, 7b, 8b, 9c, 10c und 11b in 60proz. Aceton/Wasser wird bestimmt. Die Solvolysegeschwindigkeiten der Verbindungen 2b-anti, 5e und 9d in Eisessig lassen sich mit der berechneten Spannungsenergiedifferenz (Kohlenwasserstoff-Kation) korrelieren. Die syn-Sulfonate 8b und 11b reagieren ca. 103 mal schneller als ihre anti-Isomeren 5c und 9c.- Die Isomerisierung der “inside”-Epimeren 26 und 29 zu den entsprechenden “outside”-Verbindungen 28 und 31 wird infolge des stereoselektiven “outside”-Angriffs Verhindert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811141014
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    Ein Bindungsmodell für Aminocarbin-Komplexe von Übergangsmetallen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3349-3365 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Bonding Model of Transition Metal Aminocarbyne ComplexesBy comparison of the structures of [trans-PH3(CO)4CrCNEt2]BF4 (3), mer-Br(CO)4CrCNEt2 (4), and [(CO)5CrCNEt2]BF4 (5) with the known structures of trans-Br(CO)4CrCNEt2 (1) and trans-Ph3Sn(CO)4CrCNEt2 (2) the influence of the varying metal fragment on the bonding parameters of the carbyne ligand CNEt2 is investigated. Extended-Hückel-MO calculations on models and an analysis of fragment orbital interactions between the MLn system and the aminocarbyne ligand serve a discussion of the bonding. In each complex the amino group is in conjugation with the Cr-Ccarbyne bond. The extent of conjugation is influenced by the ligand trans to the carbyne group. For cis ligands additional influences are discussed.
    Notes: Durch Vergleich der Strukturen von [trans-Ph3P(CO)4CrCNEt2]BF4(3),mer-Br(PPh3)(CO)3CrCNEt2 (4) und [(CO)5CrCNEt2]BF4 (5) mit den bereits bekannten Strukturen von trans-Br(CO)4CrCNEt2 (1) und trans-Ph3Sn(CO)4CrCNEt2 (2) wird der Einfluß des variierenden Metallkomplex-Fragments auf die Bindungsparameter des Carbin-Liganden CNEt2 untersucht. Extended-Hückel-MO-Berechnungen an Modellen und die Analyse der Fragment-Orbital-Wechselwirkungen zwischen MLn-System und Aminocarbin-Ligand dienen zur Diskussion der Bindungsverhältnisse. In allen Komplexen ist die Aminogruppe mit der Cr-Ccarbin-Bindung konjugiert. Durch die Art des zum Carbin-Rest trans-ständigen Liganden wird das Ausmaß an Konjugation verändert. Für cis-ständige Liganden müssen auch noch andere Einflüsse diskutiert wurden.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811141015
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    Synthese des Lecithin-analogen Fluorochroms {2-[3,6-Bis(dimethylamino)-10-acridinio]ethyl}(2,3-di-O-palmitoyl-D,L-1-glyceryl)-phosphat (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3372-3377 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of the Lecithin Analogous Fluorochrome {2-[3,6-Bis(dimethylamino)-10-acridinio]ethyl} 2,3-Di-O-palmitoyl-D,L-1-glyceryl PhosphateThe reaction of 3,6-bis(dimethylamino)acridine (1) with 2-bromoethanol yields 3,6-bis(dimethylamino)-10-(2-hydroxyethyl)acridinium bromide. Successive treatment of the corresponding chloride 2 with tosyl chloride, sodium iodide, and picric acid results in the formation of 3,6-bis(dimethylamino)-10-(2-iodoethyl)acridinium picrate (4). By means of silver benzyl 2,3-di-O-palmitoyl-D,L-glycerol 1-phosphate (5), 4 is transformed into the lecithin derivative (6). The structure was determined by 1H NMR spectroscopy. The results of some staining tests with LM-and Hela cells are reported.
    Notes: 3,6-Bis(dimethylamino)acridin (1) reagiert mit 2-Bromethanol unter Bildung von 3,6-Bis(dimethylamino)-10-(2-hydroxyethyl)acridinium-bromid. Das Chlorid 2 dieser Verbindung wird nacheinander mit Tosylchlorid, Natriumiodid und Pikrinsäure umgesetzt. Das resultierende 3,6-Bis(dimethylamino)-10-(2-iodethyl)acridinium-pikrat (4) bildet mit Silber-benzyl-2,3-di-O-palmitoyl-D,L-glycerin-1-phosphat (5) das gewünschte Lecithin-Analogon 6. Der Strukturbeweis wurde 1H-NMR-spektroskopisch erbracht. über Fluorochromierungsversuche von LM- und Helazellen wird berichtet.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811141017
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    Lithium-fluorsilanolate - Bausteine ketten- und ringförmiger Siloxane (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3366-3371 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lithium Fluorosilanolates - Units of Chain and Ring SiloxanesPotassium hydroxide reacts with difluorosilanes R-SiF2-R′ (1-4: R = R′ = CMe3, NC2H5(SiMe3), N-i(C3H7(SiMe3); R = CMe3, R′ = C6H5) to give the fluorosilanols R-FSiOH-R′ (7-10). The siloxane 16 is obtained in the reaction of [Me3Si)2N]2SiF2 (6) with KOH via a 1,3-silyl group migration. 7-10 react with butyllithium to give the lithium fluorosilanolates 11-14. The reaction of these lithium salts with halogensilanes leads to the formation fo the halogen functional siloxanes 15, 17-21. Lithiated 16(22) is substituted by fluorosilanes at the nitrogen (23-25). Tne cyclic siloxanes 26-28 are formed by thermal LiF elimination from 11 and 12. Dilithiated di-tert-butyldisilanol reacts with 15 to give 2,2,4,6-tetra-tert-butyl-4,6-diphenylcyclotrisiloxane (29).
    Notes: Kaliumhydroxid reagiert mit Difluorsilanen des Typs R-SiF2-R′ (1-4: R - R′ = CMe3, NC2H5(SiMe3), N-i(C3H7(SiMe3); R = CMe3, R′ = C6H5) unter Bildung der Fluorsilanole R-FSiOH-R′ (7-10). Aus [Me3Si)2N]2SiF2 (6) und KOH entsteht unter zusätzlicher 1,3-Silylgruppenwanderung das Siloxan 16. 7-10 reagieren mit Butyllithium zu den Lithium- fluorsilanolaten 11-14. Die Reaktion dieser Lithiumsalze mit Halogensilanen führt zu den halogenfunktionellen Siloxanen 15, 17-21. Lithiiertes 16 (22) wird von Fluorsilanen am Stickstoff substituiert (23-25). Die Cyclischen Siloxane 267-28 wurden bei thermischer LiF-Abspaltung aus 11 und 12 erhalten. Dilithiiertes D-tert-butyldisilanol reagiert mit 15 zu 2,2,4,6-Tetra-tert-butyl-4,6-diphenylcyclotrisiloxan (29).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811141016
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    Übergangsmetall-Carben-Komplexe, CXVIII1) Kinetische und mechanistische Untersuchungen von Übergangsmetall-Komplex-Reaktionen, VIII2) C, Cr-Wanderung von SeR in (CO)5Cr[C(SeR)NEt2]: Kinetische, mechanistische und präparative Untersuchungen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3220-3232 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbene Complexes, CXVIII1) Kinetic and Mechanistic Investigations of Transition Metal Complex Reactions, VIII2) C, Cr-Migration of SeR in (CO)5Cr[C(SeR)NEt2]: Kinetic, Mechanistic and Preparative InvestigationsOn heating in solution, [(arylseleno)(diethylamino)carbene]pentacarbonylchromium complexes, (CO)5Cr[C(SeR)NEt2], (2) [R = 4-C6H4CF3 (a), 4-C6H4Br (b), 4-C6H4F (c), C6H5 (d), 4-C6H4CH3 (e), 4-C6H4OCH3 (f), 1-C10H7 (g)] rearrange with CO-elimination and C, Cr-migration of SeR to form the corresponding trans-(arylseleno)tetracarbonyl(diethylaminocarbyne) chromium complexes, trans-RSe(CO)4CrCNEt2, (3a-g). The rearrangement follows a first-order rate law. Free carbon monoxide does not influence the reaction rate whereas the Polarity of the solvent and the type of the substituent R only influence the rate of the reaction to a very small extent. The activation enthalpies are ΔH≠ = 101-104 kj mol-1, the activation entropies ΔS = 27-33 j mol-1 K-1. Addition of PPh3 to solutions of 2d does not influence the rate of the rearrangement but leads to a different reaction product, mer-(CO)3(PPh)3(SePh)CrCNEt2 (4d). Complex (4d). is also formed by photolysis of 2d in the presence of PPh3, The compounds 3a - d and 4d are characterized by analytical and spectroscopic means, 3c, additionally by an X-ray analysis.
    Notes: Beim Erwärmen in Lösung lagern sich die [(Arylseleno)(diethylamino)carben]pentacarbonyl-chrom-Komplexe, (CO)5Cr[C(SeR)NEt2], (2) [R = 4-C6H4CF3 (a), 4-C6H4Br (b), 4-C6H4 (c_, C6H4 (d), 4-C6H4OCH3 (e) 4-C6H4OCH3 (f), 1-C10H7 (g)] unter CO-Abspaltung und C, Cr-Wanderung von SeR zu den entsprechenden trans-(Arylseleno)tetracarbonyl(diethylaminocarbin)-chrom-Komplexen, trans-RSe(CO)4CrCNEt2, (3a-g) nach einem Geschwindigkeitsgesetz erster Ordnung um. Freies Kohlenmonoxid ist ohne, die Polarität des Solvens sowie die Art des Substituenten R sind nur von geringem Einfluß auf die Reaktionsgeschwindigkeit. Die Aktivierungsenthalpien betragen ΔH≠ = 101 104 kj mol-1, die Aktivierungsentropien ΔS≠ = 27-33 j mol-1 K-1. Zusatz von PPh3 zu Lösungen von 2d beeinflußt zwar die Umlagerungsgeschwindigkeit nicht, man erhält jedoch mer-(CO)3(PPh)3(SePh)CrCNEt2 (4d) als Reaktionsprodukt. Photolyse von 2d in THF in Anwesenheit von PPh3 liefert ebenfalls 4d. Die Verbindungen 3a-d und 4d wurden analytisch und spektroskopisch gesichert, 3c zusätzlich durch eine Röntgenstrukturanalyse.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811141004
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    Cyclit-Reaktionen, IV1) Synthese von enantiomerenreinen Conduriten und Amino-Conduriten (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3242-3252 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclitol. Reactions, IV1) Synthesis of Enantiomeric Conduritols and Amino-ConduritolsThe key-intermediate for all syntheses described in this paper in the 1-O-tosylate 7of quebrachitol (1). This leads, via 8, to the 1 L-conduritol B (5) and, via 13, to the 1 L-conduritol F (17). Selective displacement of the equatorial tosyloxy group in compound 13 by azide gave 16. From this the epoxide 24 and the corresponding olefin 26 were synthesized. Treatment of 26 with triphenylphosphane gave the optically active amino-conduritol 31. The azido olefins 25 and 26 convert at high temperatures by [3,3]sigmatropic rearrangement to their enantiomers 28 and 29 respectively. These rearrangements lead to racemates.
    Notes: Die Schlüsselzwischenstufe für alle hier beschriebenen Synthesen ist das 1-O-Tosylat 7 des Quebrachits (1), aus dem über 8 die 1 L-Form des Condurits B (5) und über 13 die 1 L-Form des Condurits F (17) zugänglich sind. In 13 läßt sich selektiv die äquatoriale Tosylgruppe durch Azid zu 16 substituieren. Hieraus ist über das Epoxid 24 das Azido-Olefin 26 darstellbar, das in die 1 D-Form des Amino-Condurits 31 übergeführt wird. Die Azido-Olefine 25 und 26können bei höheren Temperaturen eine [3,3]sigmatrope Umlagerung eingehen, wobei die Enantiomeren 28 und 29 gebildet wurden. Die Umlagerung liefert somit Racemate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811141006
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    Halogenepoxide, 41) Synthese, Stabilität und Umsetzungen von 2-Chlor-2-(1-chloralkyl)oxiranen mit AgBF42) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3273-3280 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Halogen Epoxides, 4. Synthesis1) Stability and Reactions of 2-Chloro-2-(1-chloroalkyl)oxiranes with AgBF42)Reactions of 3-chloroperbenzoic acid with 2,3-dichloro-1-butene (1a), 2,3-dichloro-3-methyl-1-buten (1b) (Z)- and (E)-1,2-dichloro-2-butene (1c,d) and with 1,2-dichloro-3-methyl-2-butene (1e) afforded the corresponding epoxides (2a - e). They rearranged slowly at room temperature and fast at elevated temperatures to form the corresponding isomeric α,α′-dichloroketones (3a,b). Reactions of the epoxides with AgBF4 produced α-chloro-α′ -fluoroketones.
    Notes: Umsetzungen von 3-Chlorperbenzoesäure mit 2,3-Dichlor-1-buten (1a), 2,3-Dichlor-3-methyl-1-buten (1b), (Z)- und (E)-1,2-Dichlor-2-buten (1c,d) sowie 1,2-Dichlor-3-methyl-2-buten (1e) ergaben die entsprechenden Epoxide (2a-e). Diese lagerten sich bei Raumtemperatur langsam, bei erhöhter Temperatur rasch um in die isomeren α, α′-Dichlorketone (3a bzw. b). Durch Umsetzung mit AgBF4 wurden aus den Epoxiden α-Chlor-α′-fluorketone erhalten.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811141008
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    Synthese und Photolyse von 1,4-Dialkyl-1,4-dihydro-5H-tetrazol-5-onen und -thionen: Neue Wege zu Diaziridinonen und Carbodiimiden1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3253-3272 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Photolysis of 1,4-Dialkyl-1,4-dihydro-5H-tetrazol-5-ones ans -thiones. A Novel Approach to Diaziridinones and Carbodiimides1)The regioselective alkylation of the 1-tert-butyl-1,4-dihydro-5H-tetrazol-5-one (7) produced the 1,4-dialkyltetrazolones (8b) and c. The electron impact induced decomposition of the known, most simple tetrazolone 8a proceeded via a [3+2] cycloelimination into methyl azide and methyl isocyanate. On photolysis in acetonitrile or pentane, the tetrazolones 8 lost nitrogen and formed 1,2-cyanate. On photolysis in acetonitrile or pentane, the tetrazolones 8 lost nitrogen and formed 1,2-dialkyldiaziridinones 24, of which 24c was isolated in pure from. Very reactive alkylating reagents, e.g. methyl fluorosulfonate, trimethyloxonium tetrafluoroborate, or tert-butyl alcohol/tetrafluoroboric acid in ether, preferentially alkylated N-3 of 1-methyl-5-(methylthio)-1H-tetrazole (9a); dimethyl sulfate reacted almost equally at N-3 or N-4. In the mixture of the salts 10a and 11a obtained in this way, only 11a was demethylated at the sulfur atom by triethylamine in acetonitrile affording the easily separable tetrazolethione 5a. Diazomethane methylated 1-tert-butyl-1,4-dihydro-5H-tetrazole-5-thione (18b) predominantly at the sulfur atom. In contrast, 2-diazopropane gave approximately equal fractions of S-alkylation and N-4-alkylation producing the tetrazolethione 5c. Besides fragment ions resulting from [3+2]cycloelimination products, in the electron impact induced decomposition of the most simple tetrazolethione Sa, ions were observed which correspond to loss of nitrogen from the molecular ion. On photolysis in alkanes or acetonitrile in the temperature range between +20 and -40°C the tetrazolethiones lost nitrogen furnishing high yields of sulfur and the carbodiimides 30.
    Notes: Durch regioselektive Alkylierung des 1-tert-Butyl-1,4-dihydro-5-H-tetrazol-5-ons (7) erhält man die 1,4-Dialkyltetrazolone 8b und c. Der elektronenstoßinduzierte Zerfall des bekannten, einfachsten Tetrazolons 8a verläuft im Sinne einer [3+2]Cycloeliminierung in Methylazid und Methylisocyanat. Die Photolyse der Tetrazolone 8 in Acetonitril oder Pentan ergibt unter Stickstoffabspaltung 1,2-Dialkyldiaziridinone 24, von denen 24c in reiner Form isoliert wird. Besonders reaktive Alkylierungsmittel wie Fluorsulfonsäure-methylester, Trimethyloxonium-tetrafluoroborat oder tert-Butylalkohol/Tetrafluoroborsäure in Ether alkylieren 1-Methyl-5-(methylthio)1H-tetrazol (9a) bevorzugt an N-3, Dimethylsulfat reagiert zu etwa gleichen Teilen mit N-3 oder N-4. In der so erhaltenen Mischung der Salze 10a und 11a wird nur 11a durch Triethylamin in Acetonitril am Schwefel entmethyliert, wobei das leicht abtrennbare Tetrazolthion 5a entsteht. 1-tert-Butyl-1,4-dihydro-5H-tetrazol-5-thion (18b) wird durch Diazomethan überwiegend am Schwefel, durch 2-Diazopropan aber in ungefähr gleichen Umfang am Schwefel oder an N-4 zum Tetrazolthion 5c alkyliert. Neben den durch [3+2] Cycloeliminierung in Methylazid und Methylisothiocyanat entstandenen Fragment-Ionen beobachtet man beim elektronenstoßinduzierten Zerfall des einfachsten Tetrazolthions 5a auch Ionen, die sich auf eine Stickstoffabspaltung von dem Molekül-Ion zurückführen lassen. Die Photolyse der Tetrazolthione 5 in Alkanen oder Acetonitril bei +20 bis -40°C spaltet Stickstoff ab und ergibt hohe Ausbeuten an Carbodiimiden 30 und Schwefel.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19811141007
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    Darstellung und Eigenschaften von and Reaktionen mit metallhaltigen Heterocyclen, XVII1) P = S-haltige Metallacyclopentadiene von Mangan und Rhenium - Kristallstruktur von (OC)4MnSP(CH3)2C(CO2CH3)C(CO2CH3) und Darstellung P- und S-isomerer Heteromanganacyclopentadiene (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3281-3288 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and properties of, and Reactions with, Metal-Containing Heterocycles, XVII1) P = S-Containing Metallacyclopentadienes of Manganese and Rhenium - Crystal Structure of (OC)4MnSP(CH3)2C(CO2CH3)C(CO2CH3) and preparation of P-and S-isomeric HeteromanganacyclopentadienesThe unstable, three-membered systems (OC)4MPR12=S, which are interpreted as dissociation products of the inorganic heterocycles [-(OC)4MPR12S-]2 (1a,b), are trapped with activated alkynes of the type R2C≡CR2 with formation of the heterometallacyclopentadienes (CO)4MSP(R12)C(R2)C(R2) (2aS, 2b-e) F3C-C≡C-CF3 reacts with 1a to form also the P-isomeric heterocycle (CO)4MnP(CH3)2SC(CF3)C(CF3) (2aP). The IR spectra of 2aS and 2aP differ in the 5μ region. The P=S group behaves like an olefin. Towards hydrogenation agents the C=C bond in 2aS, 2b-d is resistent. 2b crystallizies in the monoclinic space group C2/c with Z = 8.
    Notes: Die instabilen, als Dissoziationsprodukte der anorganischen Heterocyclen [-(OC)4MPR12S-]2 (1a,b) (M = Mn, Re) aufzufassenden dreigliedrigen Systeme (OC)4MPR12=S lassen sich mit aktivierten Alkinen R2C ≡ CR2 unter Bildung der Heterometallacyclopentadiene ( CO)4MSP(R12C(R2)C(R2) (2aS, 2b-e) abfangen. Die Einwirkung von F3C-C≡C-CF3 auf 1a führt auch zu dem P-isomeren Heterocyclus (CO)4MnP(CH3)2SC(CF3)C(CF3) (2aP). 2aS und 2aP unterscheiden sich im 5-mU-Bereich der IR-Spektren. Die P = S-Gruppe verhält sich wie ein Olefin. Gegenüber Hydrierungsmitteln ist die C = C-Bindung in 2aS, 2b-d resistent. 2b kristallisiert in der monoklinen Raumgruppe C2/c mit Z = 8.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19811141009
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    Photoanilid-analoge Umlagerungen von N-Acyl-Derivaten des 5 H-Benzo[b]carbazols (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2665-2667 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoanilide-Analogous Rearrangements of N-Acyl Derivatives of 5H-Benzo[b]carbazoleThe known photo rearrangement of N-acetylcarbazole yielding carbazole ketones has also been observed for the N-acetyl and N-(2-naphthoyl) derivatives 3,4 of 5 H-benzo[b]carbazole (8), whereas N-(2-naphthoyl)carbazole (2) is photochemically almost stable. An explanation for this different behaviour on the basis of the tern schemes of the compounds studied is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140732
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    Thermolyse von 5-chlorsubstituierten (2Z,4Z)-2,4-Pentadien-thiosäure-S-alkylestern zu 2H-Pyran-2-thionen und 2H-Thiopyran-2-onen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2921-2923 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolysis of 5-Chloro-substituted S-Alkyl (2Z,4Z)-2,4-Pentadienethioates to 2H-Pyran-2-thiones and 2H-Thiopyran-2-onesThe thioates 2c, d are prepared from the corresponding acyl chlorides 1. Thermolysis of 2c at 77°C yield 2H-pyran-2-thione 3c which at 110°C rearranges to 2H-thiopyran-2-one 5c. At the same temperature 2d gives only 3d. In boiling acetic acid thermolysis 2→3→5 is competing with hydrolysis to 4H-pyran-4-one (2→4).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140823
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    Cycloadditions of Allyl Cations, 29. Acid Catalyzed Reactions of 2,3-Dimethyl-3-penten-2-ol and Cyclopentadiene in Two Phases. Formation of Seven- and Five-membered Rings (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2898-2906 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditionen von allyl-Kationen, 29. Säurekatalysierte Reaktionen von 2,3-Dimethyl-3-penten-2-ol mit Cyclopentadien in zwei Phasen. Bildung von sieben- und fünfgliedrigen Ringen2,3-Dimethyl-3-penten-2-ol (3) und Cyclopentadien wurden in verdünnter wäßriger Sulfonsäure/Pentan Gerührt. Es bildeten sich 2,3,4,4-Tetramethylbicyclo[3.2.1]octa-2,6-dien (4), die epimeren 3-Methylen-Isomeren 5a, b und zum ersten Mal auch ein fünfgliedriger Ring, nämlich 2,3,4,4-Tetramethylbicyclo[3.3.0]octa-2,6-dien (6) mit 69 - 73% Gesamtausbeute. Das bicyclische Dien 4 war Hauptprodukt und wurde leicht als kristallisierter Silbernitratkomplex (C12H18)2·AgNO3 isoliert (41-44%). In einem modifizierten Verfahren wurde die Zweiphasenreaktion bei 0°C ausgeführt. Anschließend wurden die resultierenden Alkohole chromatographisch abgetrennt und bei 50°C cyclisiert. Diese Variante ergab einen höheren Anteil des thermodynamisch stabileren, neuartigen [3.3.0]-Bicyclus 6 (4:6 = 2.6:1).
    Notes: 2,3-Dimethyl-3-penten-2-ol (3) and cyclopentadiene were stirred in dilute aqueous sulfonic acid/pentane, giving 2,3,4,4-tetramethylbicyclo[3.2.1]octa-2,6-diene (4), the epimeric 3-methyl-ene isomers 5a, b and, for the first time, also a five-membered ring, namely 2,3,4,4-tetramethylbicyclo[3.3.0]octa-2,6-diene (6) in 69 - 73% overall yield. The major bicyclic diene 4 was conveniently isolated as crystalline silver nitrate complex (C12H18)2·AgNO3 (41 - 44%). In a modified approach the two phase reaction was carried out at 0°C, the resulting alcohols were separated by chromatography and cyclized at 50°C, giving an increased proportion of the thermodynamically more stable, novel [3.3.0] bicyclic isomer 6 (4:6 = 2.6:1)
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140820
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    Ein Verfahren zur Synthese von α-Glycosiden der 3-Amino-2,3,6-tridesoxyhexopyranosen aus Glycalen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 232-239 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Procedure for an α-Glycoside Synthesis of 3-Amino-2,3,6-trideoxyhexopyranoses from GlycalsThe anomeric mixture of the hex-2-enopyranosyl azides 2 und 3, either of which adopts an equilibrium with the 3-azidoglycals 5 and 6, reacts with cyclohexanol and N-iodosuccinimide to give the 3-azido-2-iodo derivatives having α-D-altro- (4) and α-D-manno configuration (9). By reductive work-up and subsequent acetylation the synthesis of 3-acetylamino-2,3-dideoxy-α-glycosides of D-ribo (7) and of D-arabino structure (8) is achieved. By a corresponding reaction sequence starting with di-O-acetyl-L-rhamnal (10) a three step synthesis of both α-L-ristosaminide (16) as well as α-L-acosaminide (17) is realized.
    Notes: Das Anomerengemisch der Hex-2-enopyranosylazide 2 und 3, die jeweils mit den 3-Azidoglycalen 5 bzw. 6 im Gleichgewicht stehen, wird mit Cyclohexanol und N-Iodsuccinimid zu den 3-Azido-2-iod-Derivaten mit α-D-altro- (4) und α-D-Manno-Konfiguration (9) umgesetzt. Deren reduktive Aufarbeitung nebst Acetylierung ermöglicht die Synthese von 3-Acetylamino-2,3-didesoxy-α-glycosiden der D-ribo- (7) und der D-arabino-Struktur (8). In einer vergleichbaren Reaktionssequenz wird aus Di-O-acetyl-L-rhamnal (10) in nur drei Stufen die Synthese des α-L-Ristosaminids (16) sowie des α-L-Acosaminids (17) realisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140125
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    Synthese und Kristallstrukturanalyse von Boranato-bis(dimethyl-phosphoniummethylid)-Komplexen des Golds mit sechs- und zwölfgliedrigem Metallocyclus (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 441-446 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of Boranato -bis(dimethylphosphonium methylide) Complexes of Gold Containing Six- and Twelve-membered MetallocyclesThe reactions of lithium boranato-bis(dimethylphosphonium methylide), Li⊖ [CH2(CH3)2-PBH2P(CH3)2]⊖, with [(CH3)2AuCl]2 and (CO)AuCl yield the dimethylgold(III) and gold(I) complexes 3,4 containing a six-and a twelve membered metallocycle, respectively. For 3, X-ray diffraction shows a chair conformation of the six-membered ring with a square planar array of ligands at the gold center.
    Notes: Aus dem Lithiumkomplex des Boranato-bis(dimethylphosphoniummethylid)-Liganden [CH2(CH3)2PBH2P(CH3)2CH2]⊖ sind mit [(CH3)2 AuCI]2 and (CO)AuCl die Dimethylgold (III)-und Gold(I)-Verbindungen 3,4 mit sechs- bzw. zwölfgliedrigen Metallocyclen erhältlich. Die Röntgenbeugungsanalyse des Komplexes 3 zeigt eine symmetrische Sesselkonformation des sechs gliedrigen Ringsystems bei quadratisch-planarer Koordination des Goldatoms.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19811140205
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    Transanulare Wechselwirkung des Azo-Chromophors in isodrinanalogen Systemen1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 423-432 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transanular Interactions of the Azo Chromophore in Isodrin-type Systems1)The unusual transanular photoreactivity of the azo-compound 5 is also reflected in its photoelectron spectrum. The investigation of compounds 5, 13 and 14 reveals an effective interaction in 5 (through-bond and through-space) with H ij = -0.62 eV between πNN and πCC. This experimental value fits in well with known parameters of analogous isodrin-type systems. The excited states are looked into by means of semiempirical calculations with model compounds 17 and 19. Both the n-π+* and (at shorter wavelength) the π-π+* transition are conducive to an intramolecular photocycloaddition. X-ray diffraction has been used to determine the πNN,πCC-transanular distance (2.91Å).
    Notes: Die ungewöhnliche transanulare Photoreaktivität der Azoverbindung 5 spiegelt sich auch im Photoelektronenspektrum wider. Die Untersuchung der Verbindungen 5, 13 und 14 läßt eine effektive Wechselwirkung (through-bond und through-space) von Hij = -0.62 eV zwischen πNN und πNN in 5 erkennen. Dieser experimentelle Wert steht in ausgezeichneter Übereinstimmung mit bekannten Parametern analoger isodrinartiger Systeme. An den Modellverbindungen 17 und 19 werden die angeregten Zustände mit Hilfe semiempirischer Rechnungen untersucht. Sowohl der n-;π+* - als auch der kurzwellige π-π+* Übergang sind einer intramolekularen Photocycloaddition förderlich. Durch Röntgenbeugung wird der πNN, πCC-Transanularabstand zu 2.91 Å ermittelt.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19811140203
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    Synthese und Kristallstrukturanalyse von zweikernigen Gold(I)-Komplexen mit Bis(phosphino)methanid- und Phosphonium-bis(methylid)-Ligandbrücken (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 433-440 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal structure of Binuclear Gold(I) Complexes with Bis(phosphino)methanide and Phosphonium Bis(methylide) Ligand BridgesLithiated bis(diphenylphosphino)methane reacts with chloro(trialkylphosphane)gold(I) complexes to yield a gold(I) bis(diphenylphosphino)methanide, 5a, which is assigned an oligomeric structure with equivalent gold atoms by 197 Au Mößbauer spectroscopy. Similar results are obtained for a trimethylsilyl derivative 5b. From 5a and dimethyl-, diethyl-, and di-tert-butyl-methyl-phosphonium methylide R2(CH)3P—CH2, binuclear gold(I) complexes are generated, in which the metal atoms are bridged by a bis(diphenylphosphino)methanide and a dialkylphosphonium bis-methylide ligand (6a-c). X-ray diffraction analysis of 6c shows an eight-membered metallo-cycle, where two almost linear C—Au—P moieties are linked via a phosphonium and a carbanion center. the P—C—P- group with a mean d(PC) = 174 pm PCP = 123.5(15)° is clearly ylidic, and is thus inherently different from the numerous diphosphinomethane units of “A-frame” type complexes.
    Notes: Lithiiertes Bis(diphenylphosphino)methan bildet mit Chloro(trialkylphosphan)gold(I)-Komplexen ein Gold(I)bis(diphenylphosphino)methanid, 5a, dessen 197 Au-Mößbauerspektrum eine oligomere Struktur mit äquivalenten Goldatomen nachweist. Gleiches gilt für ein Trimethylsilylderivat 5b. Aus 5a werden mit Dimethyl-, Diethyl- und Di-tert-butyl-methylphosphonium-methylid R2(CH)3P = CH2 zweikernige Gold(I)-Komplexe erhalten, in denen die Metallatome durch einen Bis(diphenylphosphino)methanid- und - einen Dialkylphosphonium-bis-methylid-Liganden verbrückt sind (6a-c). Die Röntgenbeugungsanalyse von 6c zeigt einen achtgliedrigen Metallocyclus, in dem zwei fast lineare C—Au—P-Einheiten über ein Phosphonium- und ein Carbanion-zentrum verknüpft sind. Die P—C—P-Gruppe ist mit einem gemittelten d(PC) = 174 pm und PCP = 123.5 (15)° noch eindeutig ylidisch und unterscheidet sich damit prinzipiell von der PCH2P-Einheit in den zahlreichen Diphosphinomethan-Komplexen vom “A-Frame-Typ”.
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    URL: http://dx.doi.org/10.1002/cber.19811140204
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    Cycloreaktionen von α-Acylketenen mit Phosphinyldiazoalkanen und Isonitrilen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 456-467 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloreactions of α-Acylketenes with Phosphinyldiazoalkanes and IsonitrilesDepending on the half life times of both reactands, thermolysis of 2-diazo-1, 3-diketones 1 with phosphinyldiazoalkanes 3 leads via the acylketenes 2 to the formation of the hitherto unknown oxaphosphorinone 6, furanones 7, pyrazolones 9,11, and vinyl ketone 10, resp. Isonitriles 14 add to 2 affording the 2-imino-3-furanones 16; these have not yet been described. 16 readily undergo ring opening and rearrangements as well as [4 + 2]- and [2 + 2]-cycloadditions to yield 2,3- pyrroldiones 12, alkylidenepyruvamides 13, 2-hydrazonopyrroles 24, 3-pyrazolecarboxamides 25, spiro[furan-oxazines] 17, and a furylideneamidine 23 in preparative rate.
    Notes: Die Thermolyse der 2-Diazo-1,3-diketone 1 mit den Phosphinyldiazoalkanen 3 führt in Abhängigkeit der Halbwertszeiten beider Reaktionspartner über die Acylketene 2 zu dem bisher noch nicht bekannten Oxaphosphorinon 6, den Furanonen 7, Pyrazolonen 9,11 bzw. dem Vinylketon 10,2 addiert Isonitrile 14 zu den noch nicht beschriebenen 2-Imino-3-furanonen 16: diese gehen leicht Ringspaltungs-und-Umlagerungsreaktionen bzw. [4 + 2]-und[2 + 2]-Cycloadditionen ein und bilden die 2,3-Pyrroldione 12, Alkylidenbrenztraubensäureamide 13, 2-Hydrazonopyrrole 24, 3-Pyrazolcarboxamide 25, Spiro[furan-oxazine] 17 und ein Furylidenamidin 23 in präparativer Ausbeute.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140207
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    Struktur permutationsisomerer 2,3-Dihydro-1,3,2λ5 benzoxazaphosphole (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 447-455 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure of Permutation Isomeric 2,3-Dihydro-1,3,2λ5-benzoxazaphospholeso-Aminophenols 1 react with dihalogenphosphoranes to give (2-hydroxyphenylimino)phosphoranes 3 or 2,3-dihydrobenzoxazaphospholes 2, respectively. As an example, the structure of the heterocyclic compound 5,7-di-tert-butyl-2,3-dihydro-2-methyl-2,2-diphenyl-1,3,2λ5-benzoxazaphosphole (2a) was determined by X-ray crystallography. The compound crystallizes in the space group P21/c with Z = 4. The oxazaphosphole five-membered ring is attached to the trigonal-bipyramidal phosphorus in an equatorial-axial manner. The methyl group occupies an equatorial position. According to the 31P NMR spectra of the methyl31 C-enriched compound in solution an equilibrium exists between two permutation isomers, explained by the change of the methyl group from axial to equatorial position. The equilibrium is mainly determined by the reaction entropy.
    Notes: o-Aminophenole 1 reagieren mit Dihalogenphosphoranen zu (2-Hydroxyphenylimino)phosphoranen 3 bzw. zu den tautomeren 2,3-Dihydrobenzoxazaphospholen 2. Die Struktur der heterocyclischen Verbindung wurde am Beispiel des 5,7-Di-tert-butyl-2,3-dihydro-2-methyl-2,2-diphenyl-1,3,2λ5 benzoxazaphosphols (2a) bestimmt. Die Verbindung kristallisiert in der Raum gruppe P21/c mit Z = 4. Der Oxazaphosphol-Fünfring ist äquatorial-axial an den praktisch trigonal-bipyramidalen Phosphor gebunden. Die Methylgruppe besetzt eine äquatoriale Position. Nach den temperaturabhängigen31P-NMR-Spektren in Lösung der in der Methylgruppe mit 13C angereicherten Verbindung liegt ein Gleichgewicht zweier Permutationsisomerer vor, die durch Wechsel der Methylgruppe von axialer zu äquatorialer Position entstehen. Die Lage des Gleichgewichts wird von der Reaktionsentropie bestimmt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140206
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  • 286
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    Veretherungen von Diolen, Triolen und Hydroxycarbonsäure- derivaten über Thallium(I)-alkoholate Eine neue Variante der Williamson-Reaktion (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 477-487 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Etherifications of Diols, Triols, and Hydroxycarboxylic Acid Derivatives through Thallium(I) Alkoxides A New Variant of the Williamson ReactionThe etherifications listed in tables 1 and 2 are achieved by converting hydroxy-derivatives, which contain additional oxygen functions, into thallium(I) alkoxides with thallium ethoxide, and treatment with haloalkanes,. The scope and limitations of the method are discussed.
    Notes: Die in den Tabellen 1 und 2 angegebenen Veretherungen gelingen durch Überführung von Hydroxyverbindungen, die weitere Sauerstoff-Funktionen enthalten, in die Thalliumalkoholate und Umsetzung mit Alkylhalogeniden. Bedingungen für das Gelingen und die Vor-und Nachteile der Reaktion werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140209
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  • 287
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    Isolation and Structural Elucidation of Oenanthe aquatica (L.) Fruit C15 Polyacetylen Hydrocarbons (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 468-476 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Isolierung und Konfigurationsermittlung von C15-Polyacetylen-Kohlenwasserstoffen aus den Früchten von Oenanthe aquatica (L.)Aus den früher in der Volksmedizin verwendeten Früchten von Oenanthe aquatica(L) wurde eine Gruppe von C15-Polyacetylen-Kohlenwasserstoffen isoliert. Ihre Konfigurationen wurden auf Grund spektroskopischer Daten ermittelt. 2-trans-9-cis-2,9-Pentadecadien-4,6-diin (1), 2-trans-8-cis-10-trans2,8,10Pentadecatrien-4,6-diin (2) und 2-trans-8-cis-10-trans-2,8,10-Pentadecatrien-4,6-diin(3) überwiegen, während die beiden anderen geometrischen Isomeren von 2 and 3(4 und 5) in geringer Menge vorkommen. Die gefundenen Daten bestätigen die allgemein akzeptierte Meinung, daß die Biosyntheseschritte von C15- und den weiterverbreiteten C17 Polyacetylenen gleich sind.
    Notes: From the fruits of Oenanthe aquatica (L.), a plant used in the past in popular medicine, a group of C15 polyacetylene hydrocarbons have been isolated and structurally identified on the basis of spectroscopic evidence. 2-trans-9-cis-2,9-pentadecadiene-4,6-diyne (1),2-trans-8-cis-10-trans-2,8,10-pentadecatriene-4,6-diyne (2), and 2-trans-8-trans10-trans-2,8,10-pentadecatriene-4,6-diyne (3) are prominent, while the two other geometrical isomers of 2 and 3(4 and 5) exist in small amounts. The results support the generally accepted idea of a parallelism between the biosynthetic pathways of the C15 and the much more widespread C17 polyacetylenes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140208
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    Kovalente und ionische (Pentamethylcyclopentadienyl)zinn(II)-Verbindungen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 488-494 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Covalent and Ionic (Pentamethylcyclopentadienyl)tin(II)CompoundsAmong (Pentamethylcyclopentadienyl)tin(II) compounds of the type C5Me5SnX and their unsubstituted analogues C5H5SnX a separation between covalent species C5R5Sn—X and ionic structures C5R5Sn+X- is possible. With their pentagonal-pyramidal C5R5Sn+ cluster ionic compounds contain a very unusual cation. The C5R5Sn+ unit shows electrophilic character, so that ionic products can only be obtained with anions of poor nucleophilic reactivity; with more nucleophilic anions covalent species are formed, which often tend to disproportionation reactions.
    Notes: Bei den (Pentamethylcyclopentadienyl)zinn(II)-Verbindungen vom Typ C5Me5SnX und ihren unsubstituierten Analoga C5H5SnX können kovalente Spezies C5R5Sn—X und ionische Strukturen C5R5Sn+X- unterschieden werden. Letztere besitzen mit dem pentagonal-pyramidalen C5R5Sn+ Cluster ein Kation ungewöhnlicher Struktur. Die C5R5Sn+ Eigenschaften, weshalb nur mit wenig nucleophilen anionen X- ionische Verbindungen gebildet werden; mit stärker nucleophilen Resten X- entstehen kovalente Verbindungen, die häufig zu Disproportionierungsreaktionen neigen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140210
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    Cyclit-Reaktionen, II1). Darstellung von Bausteinen zur Synthese carbocyclischer Furanose-Analoga (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 346-358 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclitol Reactions, II1) Preparation of Building Units for Synthesis of Carbocyclic Furanose AnalogaThe four isomeric hydroxycyclopentenmethanols 6a to 9a can easily be made by allylhydroxylation of the epoxides 2 and 4 with phenyl selenide. In a second way the pair 8a and 9a has been synthesized from 11 via 15. As the preparation of 20 demonstrates, the functionalisation of 6a to 9a to carbocyclic furanoses is possible. The dicarboxylic diethyl esters 23 and 33 can be converted into models for carbocyclic ketofuranoses.
    Notes: Alle vier isomeren Hydroxycyclopentenmethanole 6a bis 9a sind duch Allylhydroxylierung der Epoxide 2 und 4 mit Phenylselenid gut zugänglich. Das Paar 8a und 9a wurde auf einem zweiten Weg aus 11 über 15 synthetisiert. 6a bis 9a sind zu carbocyclischen Furanosen funktionalisierbar, wie die Gewinnung von 20 zeigt. Aus den Dicarbonsäure-diethylestern 23 und 33 sind Modelle für carbocyclische Ketofuranosen darstellbar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140137
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    Übergangsmetall-Schwefelylid-Komplexe, IX1) π-Komplexe von 1-Alkyl-3,5-diphenylthiabenzol-1-oxiden mit Dicarbonylnitrosylchrom, -molybdän und -wolfram (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1-13 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Sulfur Ylide Complexes, IX1) π-Complexes of 1-Alkyl-3,5-diphenylthiabenzene 1-Oxides with Dicarbonylnitrosylchromium, -molybdenum, and -tungsten1-Alkyl-3,5-diphenylthiabenzene 1-oxide chromium complexes 2a-f1) are oxidized by NOPF6 in CH2Cl2 at -70°C, yielding the cationic dicarbonylnitrosyl complexes 3a-f. Stable analogous complexes of molybdenum and tungsten can be isolated if the sulfur atom of the ring is substituted by electron releasing and bulky groups such as CH(CH2Ph)2 or CH(SiMe3)2.
    Notes: Die 1-Alkyl-3,5-diphenylthiabenzol-1-oxid-Chromkomplexe 2a-f1) werden durch NOPF6 in CH2Cl2 bei -70°C unter Bildung der kationischen Dicarbonylnitrosyl-Spezies 3a-f oxidiert. Die Isolierung analoger stabiler Komplexe von Molybdän und Wolfram gelingt, wenn sich am Schwefel stark elektronenspendende und sperrige Substituenten wie CH(CH2Ph)2 oder CH(SiMe3)2 befinden.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140102
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    Dynamische 1H-NMR-Untersuchungen der Iminophosphoran-Benzoxazaphospholin-Tautomerie (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 14-22 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dynamic 1H-NMR-Investigation of the Iminophosphorane-Benzoxazaphospholine TautomerismThe Synthesis of many (alkyl-2-hydroxyphenylimino) Phosphoranes is described. These compounds are useful to determine by dynamic 1H-NMR investigations the activation parameters of the observed equilibrium earlier supposed. The lifetimes obtained of the tautomers A und B at 298 K have a range of 0.1 to 10 s.
    Notes: Die Synthese zahlreicher (Alkyl-2-hydroxyphenylimino)phosphorane wird beschrieben. Für das bei diesen Verbindungen zu beobachtende und früher diskutierte Gleichgewicht zwischen zwei tautomeren Formen A und B können durch 1H-NMR-Untersuchungen die Aktivierungsparameter bestimmt werden. Die Lebensdauern von A und B liegen bei 298 K zwischen 0.1 und 10 s.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140103
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  • 292
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    Nachweis der Permutationsisomerie am Phosphor durch dynamische 31P-NMR-Untersuchungen an Benzoxazaphospholinen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 23-31 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Evidence of Phosphor Permutation Isomerism by Dynamic 31P-NMR Investigations of BenzoxazaphospholinesThe studied 1,3,2-benzoxazaphospholines (8-11, 16-28, see Table 1) with different phosphorus substitutents generally show two signals in the region of 31P-NMR absorption of pentavalent phosphorus. Their typical coalescence behaviour strongly supports the existence of a dynamic equilibrium between at least two phosphorus permutation isomers. The activation parameters are determined by line shape analysis and compared with current models. The Kinetic data prove a regular mechanism for the isomerisation process.
    Notes: Zahlreiche am Phosphor unterschiedlich substituierte 1,3,4-Benzoxazaphospholine (8-11, 16-28, s. Tab.1) zeigen im Bereich de 31P-NMR-Absorption des pentavalenten Phosphors zwei Signale. Ihr typisches Koaleszenzverhalten läßt auf das Vorliegen eines dynamischen Gleichgewichts zwischen mindestens zwei Phosphor-Permutationsisomeren schließen. Die Aktivierungsparameter werden durch Linienformanalyse bestimmt und einem Modell verglichen. Aufgrund der kinetischen Daten konnte auf einen regulären Mechanismus für die Permutationsisomerisierung geschlossen werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140104
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  • 293
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    Reaktionen mit Aziridinen, XXII1) Einstufensynthese von Pyrrolidonen durch Amidoethylierung einfacher Ester mit N- Acylaziridinen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 32-48 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Aziridines, XXII1) One step Synthesis of Pyrrolidones by Amidoethylation of Simple Esters with N-AcylaziridinesSodium enolates of simple esters (2) react smoothly with N-acylaziridines 3 in THF forming 3-substituted 2-pyrrolidones 8. If the λ-position of the ester carries more than one H-atom amidoethylated pyrrolidones can result. Whilst a simple butyrolactone behaves analogously amidoethylation of coumaranone furnished mono and bis amidoethyl derivatives of coumaranone besides a pyrrolidone. In tert-butyl alcohol only extremly acidic esters like 1e and 1j could be amidoethylated.
    Notes: Natriumenolate einfacher Ester (2) lassen sich mit N-Acylaziridinen 3 in THF glatt zu 3-substituierten 2-Pyrrolidonen 8 umsetzen. Trägt der Ester in der α-Stellung mehr als ein H-Atom, könen auch amidoethylierte Pyrrolidone entstehen. Während sich ein einfaches Butyrolacton analog verhielt, ergab die Amidoethylierung von Cumaranon neben einem Pyrrolidon Mono- und Bisamidoethylderivat des Cumaranons. - In tert-Butylalkohol ließen sich nur extrem acide Ester wie 1e und 1j amidoethylieren.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19811140105
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  • 294
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    Herstellung von Pyrimido[6,1-a]isochinolinen mit Formaldehyd (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 61-66 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Pyrimido[6,1-a]isoquinolines with FormaldehydeThe isoquinolin-1-ylidenacetonitrile derivative 1 reacts with formaldehyde and hydrazine, acylhydrazines or hydroxylamine to give the 3,3′-bi(pyrimidoisoquinoline) 5 and the 3-amino-and 3-hydroxypyrimido[6,1-a]isoquinolines 6 and 8, respectively. 8 was transformed into 12, 14, and 15 which are unsubstituted at N-3 and have various oxidation levels in the pyrimidine moiety.
    Notes: Aus dem Isochinolin-1-ylidenacetonitril 1 wurden mit Formaldehyd und Hydrazin, Acylhydrazinen oder Hydroxylamin das 3,3′-Bi(pyrimidoisochinolin) 5 bzw. die 3-Amino und 3-Hydroxypyrimido[6,1a]isochinolin-Derivate 6 und 8 dargestellt. 8 ließ sich in die an N-3 unsubstituierten Derivate 12, 14 und 15 überführen, die verschiedene Oxidationsgrade im Pyrimidinring aufweisen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140107
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    Kernresonanzspektroskopische Untersuchungen an Borverbindungen, XVIII1) Eine Multikern-Untersuchung (11B, 13C, 14N, 119Sn) an B- und N-(Trimethylstannyl) aminoboranen und dem Trihydrido(trimethylstannyl)borat-Ion (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 49-60 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Spectroscopic Studies of Boron Compounds, XVIII1) A Multinuclear Study (11B, 13C, 14N, 119Sn) of B- and N-(Trimethylstannyl)aminoboranes and of a Trihydrido(trimethylstannyl)borate IonNMR Data (11B, 13C, 14N, and 119Sn) for a series of B-and N-(trimethylstannyl)aminoboranes (2-8) were determined. These are discussed comparatively. It follows that the coupling constants 3j(119SnBN13N) and 3j(119SnBN13C) are larger for compounds with the (CH3)3 Sn group trans to a 13C atom than for a cis orientation, analogously to 3j(119SnCC13C) in alkenylstannanes. Substituents influence δ11B and δ14N of aminoboranes int eh same way as they influence δ13C of olefins. NMR Parameters of some aminoboranes are used for comparison as well as those of the hitherto unknown (CH3)3SnBH3 anion.
    Notes: Magnetische Kernresonanzdaten (11B, 13C, 14N und 119Sn) für eine Reihe von B-und N-(Trimethylstannyl)aminoboranen (2-8) wurden ermittelt. Sie werden vergleichend diskutiert. Die Kopplungskonstanten 3j(119SnBN13C) und 3j119SnNB13C) der trans zur (CH3)3 Sn-Gruppe stehenden 13C-Atome sind größer als für cis-ständige in Analogie zu3j (119SnCC13C) in Alkenylstannanen. δ11 B- und δ14N- Werte werden von Substituenten in Aminoboranen in gleicher Weise beeinflußt wie δ13C in Alkenen. Zum Vergleich werden die NMR-parameter einiger Aminoborane sowie des bisher unbekannten Borats (CH3)3SnBH3 herangezogen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140106
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    Die Konfigurationszuordnung in 7-Aminobicyclo[4.1.0]heptanen1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 67-79 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Assignment of the Configuration of 7-Aminobicyclo[4.1.0]heptanes1)In bicyclo[4.1.0]heptane derivatives 1a-c with a morpholino-, a pyrrolidino-or a piperidinomoiety in 7-position the assignment to exo- endo-configuration is possible by 1H-NMR spectroscopy. The compounds 1a-c are easily obtained from enaminosulfonium salts 9. In this case endo-amino derivatives 3a-c are formed. The steric course of the substitution on bycyclo[4.1.0]heptan-7-one aminals is investigated.
    Notes: In Bicyclo[4.1.0]heptanderivaten 1a-c mit einem Morpholino-, Pyrrolidino- oder Piperidinorest in 7-Position läßt sich 1H-NMR-spektroskopisch die exo-endo-Konfiguration zuordnen. Die Verbindungen 1a-c sind auf einfache Weise aus Enaminosulfonium-Salzen 9 zugänglich. Dabei werden endo-Amino-Derivate 3a-c erhalten. Der sterische Verlauf der Substitution an Bicyclo[4.1.0]heptan-7-on-aminalen wird untersucht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140108
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    Macrocyclische quartäre Ammoniumsalze, II1) Einschlußkomplexbildung mit Anionen in Lösung (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 597-607 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Macrocyclic Quaternary Ammonium Salts, II1) Formation of Inclusion Complexes with Anions in SolutionThe Macrocyclic quaternary ammonium compounds 1 and 2 form stable inclusion complex with anionic guest molecules in aqueous solution (Tab 1 and 3). The host molecules 1 und 2 discriminate between anions according to size. The stability of the inclusion complexes depends on electrostatic as well as hydrophobic interactions. whereas the complexes of 1 are dominated by the electrostatic component, the hydrophobic interaction plays the main part in complexes with host 2. Complexes stabilities are discussed in terms of the HSAB-principle21. Based on the dependence of the formation constants on solvation, it appears that conformational changes of the host molecules determine complex stabilities too.
    Notes: Die macrotricyclischen quartären Ammoniumverbindungen 1 und 2 bilden in wäßriger Lösung mit anionischen Gastmolekülen Einschlußkomplexe (Tab. 1 und 3). 1 und 2 diskriminieren dabei Anionen nach ihrer Größe. Die Stabilität der Einschlußkomplexe hängt sowohl von der elektrostatischen als auch von der hydrophoben Wechselwirkung ab. Während in den Komplexen mit 1 die elektrostatische Komponente dominiert, übt die hydrophobe Wechselwirkung in den Komplexen mit 2 den größeren Einfluß aus. Die Komplexstabilitäten werden nach dem HSAB-Prinzip21 diskutiert. Die Abhängigkeit der Bindungskonstanten von der Solvatation läßt erkennen, daß auch Konformationsänderungen der Wirte die Komplexstabilitäten mitbestimmen.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140219
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  • 298
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    Zur Chemie hydrazinüberbrückter [14]Annulen1) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 620-629 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrazino-bridged [14]Annulenes1)Starting with [1,1-bipyrrole]-2,2′-dicarbaldehyde (6b), 4,9-diphenyl-10b,10c-diazadicyclopenta[ef,kl]heptalene-3,8-dione(4) has been obtained by Knoevenagel-condensation (to give 7b) and cyclization in boiling boron trifluoride-ether. A strong interaction between the carbonyl groups and the rest of the π-systeme is indicated by the IR spectrum (4a). The synthesis of 4.5.9.10-tetra-hydro-10b,10c-diazadicyclopenta[ef,kl]heptalene-3,8-dione (3) has been achieved from 6b by condensation to 7e, reduction to 10 using DIBAH as well as cyclization and decarboxylation. Treatment of 7a and b with DIBAH leads to the unstable dialdehydes 8 and 9, respectively.
    Notes: Ausgehend von [1,1′-Bipyrrol]-2,2′-dicarbaldehyd (6b) wird über eine Knoevenagel-Kondensation (zu 7b) und Cyclisierung in siedendem Bortrifluorid-Ether 4,9-Diphenyl-10b, 10c-diazadicyclopenta[ef,kl]heptalen-3,8-dion (4) erhalten. Das IR-Spektrum deutet auf eine starke Wechselwirkung zwischen den Carbonylgruppen und dem restlichen π-System (4a). Die Synthese des 4,5,9,10-Tetrahydro-10b,10c-diazadicyclopenta[ef,kl]heptalen-3,8-dions(3) gelang aus 6b durch Kondensation zu 7e, Reduktion mit DIBAH zu 10 und anschließende Cyclisierung und Decarboxylierung. Behandlung von 7a und b mit DIBAH führte zu den instabilen Dialdehyden 8 und 9.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140221
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  • 299
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    Reaktionen mit Radikalanionen, IV1) Synthese von Mono- und Diketonen aus Carboxyl- und α,β-ungesättigten Carbonyl-Verbindungen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 630-637 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Radicalanions, IV1) The Synthesis of Mono- and diketones from Carboxylic- and α,β-Unsaturated Carbonyl Compounds1,2-Diketones of the benzil type were obtained in the reaction of aromatic carboxylic compounds with lithium naphthalenide. The scope of this reaction was investigated. α,β-Unsaturated ketones yielded hydrodimerisation, hydrogenation and hydroxylation products.
    Notes: Durch Reaktion von aromatischen Carboxylverbindungen mit Lithium-naphthalinid ließen sich 1,2-Diketone vom Benzil-Typ darstellen. Die Anwendungsbreite dieser Reaktion wurde untersucht. Bei α,β-ungesättigten Ketonen traten unter entsprechenden Bedingungen Hydrodimerisierung, Hydrierung und Hydroxylierung auf.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140222
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  • 300
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    Neue Chromoionophore (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 638-651 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New ChromoionophoresThe synthesis and spectroscopic properties, especially shifts in light absorption upon addition of salts, of the new ionophore dyes 1, 3, 4, 10 and 11 of the anthraquinone-, naphthoquinone-, and phenol blue type are described. The observed hypsochromic and bathochromic shifts are discussed in view of the crown ether complexation in the donor or acceptor part, resp., or with 3 and 4 in view of the coordination at both donor and acceptor. Influences of the ion size and of the charge density as well as the influence of changes of the cyanine and polyene character are explained.
    Notes: Synthese und spektroskopische Eigenschaften, insbesondere Lichtabsorptions-Verschiebungen bei Salzzusatz, der neuen Ionophor-Farbstoffe 1, 3, 4, 10 und 11 vom Anthrachinon-, Naphthochinon- und Phenolblau-Typ werden beschrieben. Die hypso- und bathochromen Verschiebungen werden im Hinblick auf die Kronenether-Komplexierung im Donor- und Acceptorteil bzw. bei 3 und 4 am Donor und Acceptor erötert. Einflüsse der Ionengröße und Ladungsdichte sowie von Änderungen des Cyanin- und Polyen-Charakters werden diskutiert.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140223
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