Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1980-1984  (758)
  • 1980  (758)
  • Inorganic Chemistry  (757)
  • Nuclear reactions
  • 1
    ISSN: 1432-2048
    Keywords: Boron ; Foliar nutrition ; Nuclear reactions ; Transport (boron) ; Trifolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of white clover (Trifolium repens L.) is severely inhibited by boron starvation, but a foliar treatment with boric acid can transitorily alleviate the deficiency symptoms. The 10B(n ,α)7 Li nuclear reaction has been used to study boron transport in the plant after foliar application. More than 98% of the boron supplied remained at the point where it was applied to the leaves, and less than 2% was useful to the growth of the treated plant. This small “efficient” portion of boron was quite mobile. It was distributed to the different parts of the plant, then was transferred from the oldest parts to the newly formed leaves. Physiological and agronomical implications of these data are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1226-1234 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Simpliest Biformazan: 1,1′,5,5′-Tetraphenyl-3,3′-biformazanThe synthesis and the properties of the biformazan 9 are reported. Dehydrogenation of 9 yields the betain 20, which like the salt 21 represents the middle oxidation state between the biformazan 9 and the bis(tetrazolium salt) 22.
    Notes: Darstellung und Eigenschaften des Biformazans 9 werden beschrieben. Die Dehydrierung von 9 ergibt das Betain 20, das wie das Salz 21 der mittleren Oxidationsstufe zwischen dem Biformazan 9 und dem Bis(tetrazoliumsalz) 22 entspricht.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1235-1244 
    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, CII. Synthesis and Reactions of 1-Stanna-4-bora-2,5-cyclohexadienesHydrostannation of (dialkylamino)dialkinylboranes 1 with dimethylstannane yields 1,1-dimethyl-1-stanna-4-bora-2,5-cyclohexadienes 2. Additional 4-amino derivatives are accessible via trans-amination reactions. Solvolysis of the amino derivatives by alcohols leads to alkoxy derivatives 3. These are alkylated by aluminium alkyls or tert-butyllithium to 4-alkyl-1,1-dimethyl-1-stanna-4-boracyclohexadienes 5. A considerable difference in the chemical behaviour of the 1,1-dimethyl-and the 1,1,2,6-tetramethyl derivatives has been observed.
    Notes: Die Hydrostannierung von (Dialkylamino)dialkinylboranen 1 mit Dimethylstannan führt zu 1,1-Dimethyl-1-stanna-4-bora-2,5-cyclohexadienen 2. Über Transaminierung sind weitere 4-Amino-Derivate zugänglich. Die Solvolyse der Amino-Derivate mit Alkoholen liefert die Alkoxyderivate 3, die mit Aluminiumalkylen bzw. mit tert-Butyllithium zu 4-Alkyl-1,1-dimethyl-1-stanna-4-boracyclohexadienen 5 alkyliert werden. Zwischen den 1,1-Dimethyl- und den 1,1,2,6-Tetramethyl-Derivaten bestehen beträchtliche Unterschiede im chemischen Verhalten.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1245-1263 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sensitized Photooxygenation of Silyl Enol Ethers of Cyclic Ketonesα,β-Unsaturated and α-hydroxy ketones are accessible in prototropic ene-reactions with singlet oxygen by sensitized photooxygenation of cyclic silyl enol ethers and subsequent reduction and solvolysis. In a competing silatropic ene-reaction α-silyloxyketones are formed. Formation of different products depends on ring size, configuration and substitution. At C-6 chirally substituted 2-cyclohexenones are synthesized for the first time by sensitized photooxygenation of chiral silyl enol ethers of optically active starting ketones.
    Notes: Die sensibilisierte Photooxygenierung cyclischer Silylenolether liefert durch prototrope En-Reaktion mit Singulett-Sauerstoff nach Reduktion und Solvolyse α,β-ungesättigte Ketone sowie α-Hydroxyketone. Durch eine konkurrierende silatrope En-Reaktion werden α-Silyloxyketone gebildet. Die Produktverteilung wurde in Abhängigkeit von Ringgröße, Konfiguration und Substitution untersucht. Ausgehend von chiralen Silylenolethern optisch aktiver Ausgangsketone wurden erstmals an C-6 chiral alkylsubstituierte 2-Cyclohexenone synthetisiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1272-1279 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal Rearrangements of 8-Methoxybicyclo[5.1.0]octa-2,4-diene and 8-Methoxybicyclo[5.1.0]oct-2-eneThe equilibria 2x ⇄ 3e and 9x ⇄ 11 of the title compounds reveal a slight influence of methoxy substituents on the stability of cyclopropane rings. Reactions which involve the distal cyclopropane bond  -  the butadienylcyclopropane rearrangement of 2 and the homo-1,5-H shift of 9  -  are but modestly accelerated by methoxy groups. The vinylcyclopropane rearrangement 9x → 10 confirms the strong methoxy effect on proximal cyclopropane bonds.
    Notes: Die Gleichgewichte 2x ⇄ 3e und 9x ⇄ 11 der Titelverbindungen zeigen einen geringen Einfluß von Methoxy-Substituenten auf die Stabilität des Cyclopropanrings. Reaktionen unter Beteiligung der gegenüberliegenden Cyclopropan-Bindung  -  die Butadienylcyclopropan-Umlagerung von 2 und die Homo-1,5-H-Verschiebung von 9  -  werden durch Methoxygruppen nur mäßig beschleunigt. Die Vinylcyclopropan-Umlagerung 9x → 10 bestätigt den starken Methoxy-Effekt auf benachbarte Cyclopropan-Bindungen.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1264-1271 
    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 Phosphorus, 88. 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphaneThe reaction of 1,3-dipotassium 1,2,3-triphenyltriphosphide, K2 (PPh)3, with chlorotrimethyl-silane yields the hitherto unknown title compound Me3Si(Ph)P—P(Ph)—P(Ph)SiMe3 (1), which is remarkably stable against disproportionation reactions. In solution it forms the three diastereomers 1a (erythro/erythro), 1b (erythro/threo), and 1c (threo/threo) in a ratio of about 8:3:1, between which a dynamic equilibrium exists due to pyramidal inversion at the P-atoms. The correlation between the 31P-NMR-spectroscopically observed spin systems and the diastereomers 1a-c results from the significant dependence of the 1JPP-coupling constants on dihedral angles. The preferred trans arrangement of the bulky SiMe3- and P(Ph)SiMe3 groups at adjacent P-atoms leads to a trans-conformation of the lone electron pairs in the erythro- and to a gauche-conformation in the threo-configuration.
    Notes: Die Reaktion von 1,3-Dikalium-1,2,3-triphenyltriphosphid, K2(PPh)3, mit Chlortrimethylsilan ergibt in guter Ausbeute die bislang unbekannte Titelverbindung Me3Si(Ph)P—P(Ph)—P(Ph)SiMe3 (1), die gegenüber Disproportionierungsreaktionen bemerkenswert beständig ist. Sie bildet in Lösung die drei Diastereomeren 1a (erythro/erythro), 1b (erythro/threo) und 1c (threo/threo) im Verhältnis von etwa 8:3:1, die infolge pyramidaler Inversion der P-Atome in einem dynamischen Gleichgewicht miteinander stehen. Die Korrelation zwischen den 31P-NMR-spektroskopisch beobachteten Spinsystemen und den Diastereomeren 1a-c ergibt sich aufgrund der signifikanten Torsionswinkelabhängigkeit der 1JPP-Kopplungskonstanten. Die bevorzugte trans-Anordnung der großvolumigen SiMe3- und P(Ph)SiMe3-Reste an benachbarten P-Atomen führt bei erythro-Konfiguration zu einer trans- und bei threo-Konfiguration zu einer gauche-Konformation der freien Elektronenpaare.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1280-1289 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Inorganic Cyclopentane Variants: Organometal-Arsenic Five-Membered Rings with Fe—Co—As—Fe—As and Mn—As—As—Mn—As BackbonesBy unusual reactions the polynuclear complexes Fe2CoCp3(CO)3(AsMe2)2 (1) and Mn2(CO)7Hal-(AsMe2)3 (2, Hal=Cl, Br) were formed in moderate to good yields. Both were identified crystallo-graphically as inorganic five-membered ring systems. 1 has a Fe—Co—As—Fe—As-, 2 has a Mn—As—As—Mn—As backbone. The geometry of 1 resembles the envelope conformation, that of 2 resembles the half-chair conformation of cyclopentane.
    Notes: Durch ungewöhnliche Reaktionen entstanden in mäßigen bis guten Ausbeuten die Mehrkernkomplexe Fe2CoCp3(CO)3(AsMe2)2 (1) und Mn2(CO)7Hal(AsMe2)3 (2, Hal=Cl, Br). Beide wurden kristallographisch als anorganische Fünfring-Systeme identifiziert. 1 hat ein Fe—Co—As—Fe—As-, 2 ein Mn—As—As—Mn—As-Gerüst. Die Geometrie von 1 ähnelt der „Briefumschlag“-Konformation, die von 2 der „Halbsessel“-Konformation des Cyclopentans.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1290-1303 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Doubly Metalated Methanol.  -  Alcohol d1-and d3-ReagentsThe nucleophilic counterpart of the electrophilic hydroxymethylating protonated formaldehyde B is the hypothetical tautomer A, R=H, of methoxide. Experiments are described in which the generation of doubly metalated methanol C (= formaldehyde ketyl dianion) and its use as methanol d1-reagent are attempted. Treatment of stannylated methanol 1 with two equivalents of butyllithium furnishes a pentane-soluble reagent which hydroxymethylates electrophilic centers in moderate yields (umpolung of the formaldehyde a1-reactivity), see eq. (1) and table 3. Attempted isolation, 1H- and 13C-NMR measurements, and careful product analysis of the reaction with benzaldehyde (scheme 1 and table 2) support the view that the new reagent is actually not free lithium lithio-methoxide (2) but a tin derivative, see for instance 9 in eq. (2).  -  The O-silylated derivative 18 (=A, R=SiMe3) is likewise generated by Sn-Li-transmetallation, but cannot be trapped externally by electrophiles due to rapid Wittig rearrangement (→ 19 → 20). The readily accessible dilithio derivatives 21a and 23a can be employed as direct propanol and allyl alcohol d3-reagents, respectively.
    Notes: Das nucleophile Pendant zum elektrophilen Hydroxymethylierungsmittel B, dem protonierten Formaldehyd, ist das fiktive Methanolat-Tautomere A, R=H. Es werden Versuche zur Erzeugung des doppelt metallierten Methanols C (= Formaldehyd-Ketyldianion-Derivat) und dessen Verwendung als Methanol-d1-Reagenz beschrieben. Durch Umsetzung des stannylierten Methanols 1 mit zwei Äquivalenten Butyllithium erhält man ein pentanlösliches Reagenz, welches elektrophile Zentren in mäßigen Ausbeuten hydroxymethyliert (Umpolung der Formaldehydreaktivität), Gl. (1) und Tab. 3. Isolierungsversuche, 1H- und 13C-NMR-Messungen sowie sorgfältige Produktanalyse der Reaktion mit Benzaldehyd (Schema 1 und Tab. 2) stützen die Hypothese, daß das erzeugte Reagenz nicht das freie Lithium-lithiomethanolat (2), sondern ein Sn-Derivat, z. B. 9 in Gl. (2) sein dürfte.  -  Das ebenfalls durch Sn/Li-Transmetallierung erzeugte O-Silylderivat 18 [=A, R=Si(CH3)3] läßt sich wegen zu schneller Wittig-Umlagerung (→ 19 → 20) nicht extern mit Elektrophilen abfangen, während die leicht zugänglichen Dilithiumderivate 21a und 23a als direkte Propanol- bzw. Allylalkohol-d3-Reagenzien fungieren.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Coordinated Ligands, VIII. Synthesis, Reactivity, and Structure of Molybdenum- and Nickel Carbonyl Complexes of 1,3-Bis(phenylphosphino)propane1,3-Bis(phenylphosphino)propane reacts with Ni(CO)4, C7H8Mo(CO)4, and Mo(CO)6 to produce complexes of the type (CO)nM(PhPH—C3H6—PPhH) (n = 4, M=Mo; n = 2, M=Ni) and oligomers thereof. These compounds were also obtained by the reaction of phosphido complexes (CO)nM(PhPHM′)2 (n = 4, M=Mo, M′=Li; n = 2, M=Ni, M′=Li, Na) with 1,3-dibromopropane. The complexes (CO)nM(PhPH—C3H6—PPhH) may be deprotonated with methyllithium. The reactions of the phosphido complexes thus obtained are discussed. From the meso-form of (CO)2Ni(PhPH—C3H6—PPhH), which crystallizes in the space group Cmc21, an x-ray structure analysis has been performed.
    Notes: 1,3-Bis(phenylphosphino)propan reagiert mit Ni(CO)4, C7H8Mo(CO)4 und Mo(CO)6 unter Bildung von Komplexen des Typs (CO)nM(PhPH—C3H6—PPhH) (n = 4, M=Mo; n = 2, M = Ni) und deren Oligomeren. Diese Verbindungen werden auch bei Umsetzung von Phosphidokomplexen (CO)nM(PhPHM′)2 (n = 4, M=Mo, M′=Li; n = 2, M=Ni, M′=Li, Na) mit 1,3-Dibrompropan erhalten. Die Komplexe (CO)nM(PhPH—C3H6—PPhH) lassen sich mit Methyllithium deprotonieren. Über Reaktionen der dabei gebildeten Phosphidokomplexe wird berichtet.  -  Von der Mesoform von (CO)2Ni(PhPH—C3H6—PPhH) (1), das in der Raumgruppe Cmc21 kristallisiert, wurde eine Röntgenstrukturanalyse durchgeführt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1385-1393 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Properties, and Structure of Di-μ-halogeno-bis[dicarbonyl(tri-tert- butylphosphane)-ruthenium(I)](Ru—Ru)Ruthenium trichloride trihydrate (1) reacts with carbon monoxide and tri-tert-butylphosphane (2) in 2-methoxyethanol to form di-μ-chloro-bis[dicarbonyl(tri-tert- butylphosphane)ruthenium(I)]-(Ru—Ru) (3). The corresponding bromo- (5), and iodo derivatives (6) are formed either from 3 by halogen exchange using LiBr or Nal or by the reaction of di-μ-halogeno-bis[tricarbonylhalogeno-ruthenium(II)] with 2. The crystal structure of 5, has been determined from single crystal X-ray data. The compound crystallizes with 4 molecules in a unit cell of symmetry P21/a in the monoclinic system.
    Notes: Rutheniumtrichlorid-trihydrat (I) reagiert mit Kohlenmonoxid und Tri-tert-butylphosphan (2) in 2-Methoxyethanol unter Bildung von Di-μ-chloro-bis[dicarbonyl(tri-tert- butylphosphan)ruthenium(I)](Ru—Ru) (3). Die entsprechenden Brom- (5) und Iod-Derivate (6) entstehen entweder aus 3 durch Halogenaustausch mittels LiBr oder NaI oder durch Umsetzung von Di-μ-halogeno-bis[tricarbonylhalogeno-ruthenium(II)] mit 2. Die Kristallstruktur von 5 wurde bestimmt. Die Verbindung kristallisiert mit 4 Molekülen in der monoklinen Elementarzelle der Symmetrie P21/a.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1566-1574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure and Reactions of the Phosphinic Ester Me2P(:O)OC(CF3)2C(CF3)2OHThe product obtained from the reaction of the Me3SiO-functional 1,3,2λ5-dioxaphospholane 1 with water or hydrogen chloride has the structure 2b of a phosphinate; the expected isomeric hydroxyphosphorane 2a has not been observed. The structure of 2b has been determined by X-ray crystal structure analysis. Crystals of 2b are monoclinic; space group P21/c. In the crystalline state 2b forms dimers, as a result of strong hydrogen bonding between the P(:O)-group of one molecule and the OH-group of a second molecule. Reactions of 2b with chlorotrimethylsilane in the presence of triethylamine resulted in cyclisation with formation of the phosphorane 1. With thionyl chloride 2b gave the cyclic chlorophosphorane 3, while 2b and 3 reacted with formation of the cyclic anhydride 4 of the hypothetical hydroxyphosphorane 2a.
    Notes: Das Produkt der Umsetzung des Me3SiO-funktionellen 1,3,2λ5-Dioxaphospholans 1 mit Wasser oder Chlorwasserstoff besitzt die Konstitution 2b eines Phosphinsäureesters; das erwartete isomere Hydroxyphosphoran 2a wird nicht beobachtet. Die Struktur von 2b wurde durch Röntgen-analyse bestimmt. 2b kristallisiert monoklin, Raumgruppe P21/c, und bildet im kristallinen Zu-stand Dimere, in denen starke Wasserstoffbrückenbindungen zwischen der P(:O)-Gruppe eines Moleküls und der OH-Gruppe eines zweiten Moleküls vorliegen. Durch Umsetzung von 2b mit Chlortrimethylsilan in Gegenwart von Triethylamin erfolgt Cyclisierung zum Phosphoran 1. Umsetzung von 2b mit Thionylchlorid liefert das cyclische Chlorphosphoran 3, während aus 2b mit 3 das Anhydrid 4 des hypothetischen Hydroxyphosphorans 2a gebildet wird.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1584-1591 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycyclic Compounds, XVII. 1,4-Carbonyl Group Transposition Studies in the Tetrahydrobenzocycloheptenone SeriesThe protected carbonyl group in the seven-membered ring of the oxanorbornadiene 1 is shifted by the 1,4-carbonyl group transposition sequence 1 → 4 → 5 → 3 into the ortho-position of a methoxycarbonyl group. Thereby 1,2- and 3,4-disubstituted tetrahydrobenzocyclohepten-5-one derivatives 2 and 3 are available as well starting from 1. The compound 5 exists in solution predominantly as arene oxide 5B. Experiments to cleave the dioxolane ring led under additional formation of a five-membered ring to the lactol ethers 6.
    Notes: Die als Dioxolan geschützte Carbonylgruppe im Siebenring des Oxanorbornadiens 1 wird durch die 1,4-Carbonylgruppen-Transpositionsfolge 1 → 4 → 5 → 3 in die ortho-Position zu einer Methoxycarbonylgruppe verschoben. Dadurch werden ausgehend von 1 sowohl 1,2- als auch 3,4-disubstituierte Tetrahydrobenzocyclohepten-5-on-Derivate 2 und 3 zugänglich. Das Zwischen-produkt 5 liegt in Lösung überwiegend als Arenoxid 5B vor. Versuche zur Dioxolanspaltung führten unter zusätzlichem Fünfringschluß zu den Lactolethern 6.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1592-1602 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Biologically Important Carbohydrates, 21 Asymmetrically Induced Synthesis of Amino Sugars: Methyl 4-O-Acetyl-3-acetylamino-2,3,6-trideoxy-α-D-xylo-hexopyranosidetrans-4-Hexenal-((2R, 3R)tartaric acid dimethyl ester acetal) (6) is aminated in allylic position with metallic selenium and chloramine-T yielding the easily separable 3-tosylamino derivatives with D-(7) and L-glycero-configuration (8) at C-3. 7 is hydroxylated with osmium tetroxide giving the 4,5-dihydroxy-3-tosylamino-D-xylo-hexanal acetal 9 with high selectivity. By splitting off the carbonyl protecting group from 9 with HCl in methanol methyl 2,3,6-trideoxy-3-tosylamino-hexoside 11 is obtained. Detosylation of 11 with sodium in liquid ammonia and peracetylation gives methyl 4-O-acetyl-3-acetylamino-2,3,6-trideoxyhexoside 13 with D-configuration. The constitution of 11 and 13 is proved by mass spectrometry and the α-xylo-configuration is determined by means of the 1H-NMR spectra.
    Notes: trans-4-Hexenal-((2R, 3R)-weinsäure-dimethylester-acetal) (6) liefert nach allylischer Aminierung mit metallischem Selen und Chloramin-T die gut trennbaren 3-Tosylamino-Derivate mit D- (7) und L-glycero-Konfiguration (8) an C-3. 7 wird mit Osmiumtetroxid hoch selektiv zum 4,5-Dihydroxy-3-tosylamino-D-xylo-hexanal-acetal 9 hydroxyliert, aus dem durch Abspaltung der Carbonylschutzgruppe mit HCl in Methanol das Methyl-2,3,6-tridesoxy-3-tosylaminohexosid 11 entsteht. Dessen Detosylierung mit Natrium in flüssigem Ammoniak führt nach Peracetylierung zum D-konfigurierten Methyl-4-O-acetyl-3-acetylamino-2,3,6-tridesoxyhexosid 13, dessen Konstitution durch Massenspektrometrie und dessen α-xylo-Konfiguration durch 1H-NMR-Untersuchungen bewiesen wird.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1612-1622 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Extreme Steric Hindrance: Synthesis and Structure of the Tetra(tert-butyl)phosphonium Cation  -  a Case of T-SymmetryStarting from [(CH3)3C]3P and following a series of quaternisation and ylidation steps under carefully controlled conditions, the [(CH3)3C]4P+ cation could be synthesized for the first time: [(CH3)3C]3P → [(CH3)3C]3PCH3⊕ → [(CH3)3C]3P=CH2 → [(CH3)3C]3PCH2CH3⊕ → [(CH3)3C]3-P=CHCH3 → [(CH3)3C]3PCH(CH3)2⊕ → [(CH3)3C]3P=C(CH3)2 → [(CH3)3C]4P⊕. All intermediates were isolated. The tetra(tert-butyl)phosphonium cation was further characterized in the form of the iodide and tetrafluoroborate by means of all spectroscopic methods available. An X-ray diffraction analysis of the BF4 salt showed a face-centered cubic lattice with a superstructure (space group F43c  -  Td5). The cation has T-symmetry as predicted by theoretical force field calculations with a tert-butyl twist of 14°. Due to the extreme steric hindrance, the P—C bond distances are elongated and the C—C—C angles compressed.
    Notes: Ausgehend von [(CH3)3C]3P konnte über eine Abfolge von Quartärisierungs- und Ylidierungsstufen erstmals das [(CH3)3C]4P⊕-Kation synthetisiert werden: [(CH3)3C]3P → [(CH3)3C]3PCH3⊕ → [(CH3)3C]3P=CH2 → [(CH3)3C]3PCH2CH3⊕ → [(CH3)3C]3P=CHCH3 → [(CH3)3C]3PCH-(CH3)2⊕ → [(CH3)3C]3P=C(CH3)2 → [(CH3)3C]4P⊕. Alle Zwischenprodukte wurden isoliert. Das Tetra(tert-butyl)phosphonium-Kation wurde als Iodid und Tetrafluoroborat spektroskopisch vollständig charakterisiert. Eine Röntgenbeugungsanalyse des BF4-Salzes zeigte, daß eine kubisch-flächen-zentrierte Packung mit Überstruktur vorliegt (Raumgruppe F43c  -  Td5). Das Kation besitzt die theoretisch vorhergesagte T-Symmetrie mit einem tert-Butyl-Twist von 14°. Wegen der extremen sterischen Hinderung sind überdies die P—C-Abstände verlängert und die C—C—C-Winkel verengt.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1632-1635 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations on Diazo Compounds and Azides, XXXVII. Diazo Group Transfer onto 2,3-Diphenylthiirene 1,1-Dioxide with DiazoalkanesThe thiirene 1,1-dioxide 6 reacts with diazoalkanes (2a - d) not only under diazo group transfer to give 9a or 10b and c but also under loss of sulfur dioxide to form pyrazoles (11b, c and 8d). The bicycles 7 are intermediates of both reactions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1320-1327 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Derivatives of 1,3-Benzodioxole, 45. Syntheses of Substituted DihydronaphthalenecarbaldehydesAt room temperature the reaction of the Vilsmeier complex with the propenyl compounds 1a and b leads to the acrylaldehydes 2a and b. A rise of temperature up to 100°C yields the dimethylammonium salts 3a and b, which can be hydrolized to the indanones 4a and b. The dihydronaphthalenecarbaldehydes 6a - g are obtained by treatment of the allyl compounds 5a - g with the Vilsmeier reagent at room temperature. The aldehydes 6c and f were subjected to Palladium catalysed reduction leading to the naphthalenes 8c and f, which are prepared by an alternative route.
    Notes: Die Einwirkung des Vilsmeier-Komplexes auf die Propenylverbindungen 1a und b führt bei Raumtemperatur zu den Acrylaldehyden 2a und b. Bei 100°C entstehen die Dimethylammoniumsalze 3a und b, die zu den Indanonen 4a und b hydrolysierbar sind. Die Behandlung der Allylverbindungen 5a - g bei Raumtemperatur mit Vilsmeier-Reagenz ergibt die Dihydronaphthalincarbaldehyde 6a - g. Die Aldehyde 6c und f wurden durch Palladium-Katalyse zu den Naphthalinen 8c und f abgebaut, die zum Konstitutionsbeweis auf unabhängigem Wege dargestellt wurden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1524-1534 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nucleosides, XXXII. Ribosylations of 7-Oxo-7,8-dihydrolumazine and its 6-Methyl- and 6-Phenyl DerivativesRibosylation reactions of 7-oxo-7,8-dihydrolumazine (1) and its 6-methyl- (2) and 6-phenyl derivative, respectively, are described. Treatment of the trimethylsilyl derivatives 6 - 8 with 2,3,5-tri-O-benzoyl-1-bromo-D-ribofuranose (9) in the presence of Hg-salts leads to mixtures of the corresponding N-1-mono- (11 - 13) an N-1,N-3-diribosides (17 - 19), whereas the analogous reaction with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (10) and SnCl4 gave N-3-nucleosides (23 - 25). N-8-Substitution has not been observed. On debenzoylations the free nucleosides 14 - 16, 22, and 26 - 28 are formed. The structures of the newly synthesized compounds have been established by UV- and NMR spectra as well as pK determinations.
    Notes: 7-Oxo-7,8-dihydrolumazin (1), sein 6-Methyl-(2) und 6-Phenyl-Derivat (3) werden in Form ihrer Trimethylsilyl-Derivate 6 - 8 Ribosidierungsreaktionen unterworfen. 2,3,5-Tri-O-benzoyl-1-brom-D-ribofuranose (9) führt unter Hg-Salz-Katalyse zu den entsprechenden N-1-Mono-(11 - 13) und N-1,N-3-Diribosiden (17 - 19), während mit 1-O-Acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose (10) und SnCl4 die N-3-Nucleoside 23 - 25 gebildet werden. Eine N-8-Substitution wird nicht beobachtet. Entbenzoylierungen führen zu den freien Nucleosiden 14 - 16, 22 und 26 - 28. Die Verbindungen werden durch UV- und NMR-Spektren sowie pK-Werte charakterisiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 24-35 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrogen Transfer Reactions, Part 4. Mechanism in the Stereoselective Hydrogen Transfer from 1,2-Dihydronaphthalene to TetracyanoetheneThe hydrogen transfer between 1,2-dihydronaphthalene (1) and tetracyanoethene (2) is highly stereoselective. Kinetic isotope effects exclude an electrocyclic reaction and support an ionic multistep mechanism. Stereoselectivity is caused by steric fixation in the intermediate ion pair.
    Notes: Die Wasserstoffübertragung von 1,2-Dihydronaphthalin (1) auf Tetracyanethen (2) verläuft hoch stereoselektiv. Die kinetischen Isotopeneffekte widerlegen aber einen elektrocyclischen Ablauf und beweisen, daß ein ionischer, mehrstufiger Mechanismus vorliegt. Ein sterisch fixiertes Ionenpaar ist Ursache der Stereoselektivität.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 42-54 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Metal-Metal Bonds. Polynuclear Complexes via Cleavage of Metal-Metal Bonds by Functional LigandsIn arsenic-bridged dinuclear complexes 1-3 Fe—Co, Fe—Fe, and Fe—Mn bonds could be opened by addition of Me2E—NMe2 (E = P, As). From the resulting Me2E—NMe2 containing dinuclear complexes 4-6 with HCl in a few cases the corresponding Me2ECl complexes 7 were prepared. While FeMn(CO)8(μ-AsMe2) (1) reacted with Me2PCl normally under addition, with Me2AsCl by addition and rearrangement the compound [(CO)4Fe(μ-AsMe2)2Mn(CO)4]+-[(CO)4Fe—AsMe2—Mn(CO)4Cl]- (8) with dinuclear cations and anions was formed which was characterized crystallographically. With Me2P—PMe2 the metal-metal bonds were opened with formation of complexes with a M—As—M—P—P framework (14-16). These reacted as organometallic Lewis bases once more in the same way whereby in a planned fashion tetranuclear complexes 17-22 with M—As—M—P—P—M—As—M backbones were prepared.
    Notes: In arsenverbrückten Zweikernkomplexen 1-3 ließen sich Fe—Co-, Fe—Fe- und Fe—Mn-Bindungen durch Addition von Me2E—NMe2 (E = P, As) öffnen. Aus den entstandenen Me2E—NMe2 enthaltenden Zweikernkomplexen 4-6 konnten mit HCl in einigen Fällen die entsprechenden Me2ECl-Komplexe 7 hergestellt werden. Während FeMn(CO)8(μ-AsMe2) (1) mit Me2PCl normal unter Addition reagierte, bildete sich mit Me2AsCl durch Addition und Umlagerung die Verbindung [(CO)4Fe(μ-AsMe2)2Mn(CO)4]+ [(CO)4Fe—AsMe2—Mn(CO)4Cl]- (8) mit Zweikern-Kationen und -Anionen, die kristallographisch charakterisiert wurde. Mit Me2P-PMe2 wurden die Metall-Metall-Bindungen unter Bildung von Komplexen mit M—As—M—P—P-Gerüst geöffnet (14-16). Diese reagierten als metallorganische Lewis-Basen erneut im gleichen Sinne, wodurch sich gezielt Vierkernkomplexe 17-22 mit M—As—M—P—P—M—As—M-Baueinheiten darstellen ließen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four- and Five-membered Phosphorus Heterocycles, 39. Structural Changes on the [2 + 2] Cycloaddition of Ketones to AzaphospholesThe reaction of 5H-1,2λ5-azaphospholes 1 with ketones yields stable [2 + 2] cycloadducts 3 possessing a bicyclo[3.2.0]heptane skeleton with pentacoordinate phosphorus in a bridge-head. It shows once again the enhanced addition capability of five-membered cyclic phosphazenes in comparison to acyclic phosphazenes. We explain this enhancement in terms of the lesser degree of reorganisation necessary for cyclic species on going from phosphorus tetra- to pentacoordination. Molecular structures of the azaphosphole 1a and its trifluoroacetone adduct 3b have been determined by X-ray analysis and are discussed. Their comparison proves the relatively small changes in phosphorus bond angles and demonstrates also the strain in the σ4P- and its decrease in the σ5P-ring.
    Notes: Die Umsetzung von 5H-1,2λ5-Azaphospholen 1 mit Ketonen führt zu stabilen [2 + 2]-Cycloaddukten 3 mit Bicyclo[3.2.0]heptan-Gerüst und pentakoordiniertem Phosphor im Brückenkopf. Sie belegt das im Vergleich zu acyclischen Phosphazenen gesteigerte Additionsvermögen der Fünfringphosphazene, das wir auf den niedrigen Reorganisationsaufwand für den Übergang von der Phosphortetra- in die -pentakoordination zurückführen. Vom Azaphosphol 1a und seinem Trifluoraceton-Addukt 3b werden die röntgenographisch bestimmten Molekülstrukturen diskutiert. Ihr Vergleich bestätigt die relativ geringen Winkeländerungen am Phosphor und läßt auch erkennen, daß diese durch die Ringspannung im σ4P- und die Spannungsminderung im σ5P-Ring bedingt sind.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 90-103 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Structure of 2,6-DiphenylhomotropilideneThe structure of the title compound 1 was determined be means of NMR spectroscopy as well as by force field calculations and X-ray structure analysis. The results prove the ring system to be remarkably flexible for the free molecule, the molecule in solution and in the crystalline state. Furthermore, it shows the relation between conformation and ring inversion with increasing molecular interactions. The variation of the structure angles α and β follows from the relation α = 1.4 β and encloses the transition state of the ring inversion. Under the same conditions the seven-membered ring is more puckered than the unsubstituted homotropilidene. The phenyl fragments may prefer coplanar orientations to the double bonds of the seven-membered ring, but the torsion of these groups requires only little energy.
    Notes: Die Struktur der Titelverbindung 1 wurde durch NMR-Spektroskopie, durch Kraftfeldrechnungen und durch eine Röntgenstrukturanalyse bestimmt. Die Ergebnisse beweisen sowohl für die Struktur ohne Medium als für die Struktur in der Lösung und im Kristall eine erhebliche Flexibilität des Ringsystems und zeigen die Zusammenhänge zwischen Konformation und Ringinversion bei zunehmenden intermolekularen Wechselwirkungen. Die Variation der Strukturwinkel α und β folgt der Beziehung α = 1.4β. Sie schließt damit den Übergangszustand der Ringinversion ein. Die Aufwellung des Siebenrings ist unter vergleichbaren Bedingungen größer als im unsubstituierten Homotropiliden. Die Phenylringe bevorzugen zwar koplanare Orientierung zu den Doppelbindungen des Siebenrings, jedoch wird für die Torsion der Substituenten nur ein geringer Energieaufwand benötigt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 142-151 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of (Dichlorophosphinyl)methanesulfonyl ChlorideSubstitution of chlorine by fluorine in (dichlorophosphinyl)methanesulfonyl chloride (2) Cl2P(O)CH2SO2Cl leads to the fluorides F2P(O)CH2SO2X (X = Cl, F); their reactions leading to the fluorophosphorane F4PCH2SO2F and fluorophosphate anions of the type [F5PCH2SO2X]- and [O(F)P(O)CH2SO2X]- (X = Cl, F) were investigated. Hydrolysis of 2 yields the acid (HO)2P(O)CH2SO2OH, from which esters and amides have been derived. The conversion of the esters to α,β-unsaturated sulfonic acid derivatives via the Horner-Wittig reaction is also described.
    Notes: Substitution von Chlor durch Fluor in (Dichlorphosphinyl)methansulfonylchlorid (2), Cl2P(O)CH2SO2Cl liefert die Fluoride F2P(O)CH2SO2X (X = Cl, F), deren Umwandlung zum Fluorphosphoran F4PCH2SO2F und zu Fluorophosphat-Anionen des Typs [F5PCH2SO2X]- bzw. [O(F)P(O)CH2SO2X]- (X = Cl, F) untersucht wird. Die Hydrolyse von 2 führt zur Säure (HO)2P(O)CH2SO2OH, von der Ester und Amide dargestellt werden. Die Ester werden in einer Horner-Wittig-Reaktion in α,β-ungesättigte Sulfonsäureverbindungen umgewandelt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 152-164 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Pair Mechanism in the Aromatic Rearrangement of O-Alkylsulfinyl-N-phenylhydroxylaminesO-Alkylsulfinyl-N-benzoyl-N-phenylhydroxylamines (3) rearrange at - 70°C to give sulfonamides 4, o-sulfones 5, p-sulfones 6, and o-sulfonates 7. These reactions proceed intramolecularly via the radical pair 13 by [1,2]-, [2,3]- and [2,5]-shifts in both radicals as proved both by experiments with 18O-indicated N-benzoyl-N-phenylhydroxylamine (1) and by strong 13C-CIDNP effects. The third oxigen in the o-sulfonate 7 is donated by a second molecule of the educt 1.
    Notes: O-Alkylsulfinyl-N-benzoyl-N-phenylhydroxylamine (3) lagern sich schon bei ca. - 70°C um in Sulfonamide 4, o- und p-Sulfone 5 und 6 sowie in o-Sulfonate 7. Alle Reaktionen verlaufen intramolekular über das Radikalpaar 13 unter [1,2]-, [2,3]- und [2,5]-Verschiebungen in den Radikalen. Dies zeigen Versuche an 18O-indiziertem N-Benzoyl-N-phenylhydroxylamin (1) sowie die starken 13C-CIDNP-Effekte. Der zur Bildung des o-Sulfonats 7 benötigte Sauerstoff entstammt einem zweiten Molekül des Edukts 1.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 183-192 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Substituted Hydrazones with Thionyl Chloride and Sulfuryl ChlorideTreatment of acetylhydrazones 2, ethoxycarbonylhydrazones 3, p-tolylsulfonylhydrazones 4 or semicarbazones 5 with thionyl chloride leads to the 1,2,3-thiadiazoles 6a-o. Sulfuryl chloride on the other hand accomplishes the transfer of chlorine without incorporating a sulfur atom. The new synthesized 1,2,3-thiadiazoles 6g-o are characterized in detail by spectroscopic methods.
    Notes: Die Einwirkung von Thionylchlorid auf Acetylhydrazone 2, Ethoxycarbonylhydrazone 3, p-Tolylsulfonylhydrazone 4 oder Semicarbazone 5 führt zu den 1,2,3-Thiadiazolen 6a-o. Sulfurylchlorid dient dagegen lediglich als Chlorüberträger; Schwefel wird nicht eingebaut. Für die neu auf diesen Wegen synthetisierten 1,2,3-Thiadiazole 6g-o wird eine eingehende spektroskopische Charakterisierung durchgeführt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbial Transformations of Steroids, XVII. Preparation of Several Mono- and Diketo-structures of D-Homo-4-pregnene-3,20-dione and D-Homo-1,4-pregnadiene-3,20-dione11α- (2) and 15α-monohydroxy- (3), 6β,11α-(4), 11α,15α- (5), 12β,15α- (6), 15α,16α- (7), 7β,11α- (8), 11β,17α- (9), 7β,17α-dihydroxy- (11), and 17α-hydroxy-11-oxo-D-homoprogesterone (10) were prepared by microbiological transformations of D-homoprogesterone (1) with various fungi. The compounds were oxidized by the method of Jones before and after microbiological 1,2-dehydrogenation with Bacillus lentus to the corresponding keto-structures 12 to 17 and 20 respectively 26 to 30. The 14α-hydroxy-11-ketone 18 and 7α,14α-dihydroxy-11-ketone 19 were obtained by microbiological hydroxylation of the 11-ketone 12 with Curvularia lunata. Penicillium lilacinum degraded D-homoprogesterone (1) to D-homotestosterone.
    Notes: Durch mikrobiologische Umwandlung von D-Homoprogesteron (1) mit verschiedenen Pilzstämmen wurden 11α- (2) und 15α-Monohydroxy- (3), 6β,11α- (4), 11α,15α- (5), 12β,15α- (6), 15α,16α- (7), 7β,11α- (8), 11β,17α- (9), 7β,17α-Dihydroxy- (11) und 17α-Hydroxy-11-oxo-D-homo-progesteron (10) hergestellt. Die Verbindungen wurden vor und nach mikrobiologischer 1,2-Dehydrierung mit Bacillus lentus zu den entsprechenden Ketostrukturen 12 - 17 und 20 bzw. 26 - 30 nach Jones oxidiert. Ein 14α-Hydroxy-11-keton 18 und 7α,14α-Dihydroxy-11-keton 19 wurden durch mikrobiologische Zweithydroxylierung des 11-Ketons 12 mit Curvularia lunata erhalten. Penicillium lilacinum baute D-Homoprogesteron (1) zu D-Homotestosteron ab.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 226-232 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structures of the S3N2+ Radical Cation in S3N2+SO3CF3- · 1/2 CH3CN and of S3N2(NSO2F)The molecular and crystal structures of S3N2+SO3CF3- · 1/2 CH3CN (1) and S3N2NSO2F (2) were determined from single crystal X-ray diffraction data. The S3N2+ radical cation in 1 is planar, two cations being connected through weak S—S bonding interactions to form dimers with a chair configuration. The S3N2 ring of 2, in which the NSO2F group is covalently bonded to one of the S atoms of the S — S group, is not planar; the S — S bond is weaker than in 1.
    Notes: Die Röntgenstrukturanalysen von S3N2+SO3CF3- - 1/2 CH3CN (1) und S3N2NSO2F (2) zeigen in 1 ein planares S3N2+-Radikalkation, wobei zwei Kationen über schwache S-S-Wechselwirkungen zu sesselförmigen Dimeren assoziiert sind. Der an einem S-Atom der S — S-Gruppe substituierte S3N2-Ring in 2 ist nicht planar; die S — S-Bindung ist schwächer als in 1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. XXIX 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 808-810 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Anchimerically Enhanced Homolyses, V. Fluoride Ion Catalysed Rearrangements of Benzyl 9-(Trimethylgermyl)-9-fluorenyl EtherThe thermal rearrangement (homolysis) of the germanium compound 1d into 4d is considerably slower than that of the analogous Si compound 1c. Thus, a correlation is suggested between the velocity of the rearrangement and the strength of the new bond to oxygen. The rearrangement 1d→4d is also induced by fluoride ions at room temperature.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 811-818 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Trichlorovinylketene Imines from Perchlorobutenyne and Cycloaddition of Trichloroacetyl Isocyanate to 4H-1,3-Oxazin-4-onesThe reaction of perchlorobutenyne (1) with primary aliphatic amines leads to the ketene imines 3. The stability of 3 increases with spatial requirement of amino groups. Therefore only 3e - g may be isolated in pure form. Hydrolysis of 3 yields the carboxamides 4. 4e is furthermore hydrolyzed to the known acid 5. - The cycloaddition reaction of 3 with trichloroacetyl isocyanate is followed by tautomerization to the 4H-1,3-oxazin-4-ones 8 in good yield. When trated with aqueous ethanol or absolute methanol ring opening of 8 occurs with formation of substituted malonamides 7 and 10, respectively. The structure of 8 is confirmed by further degradation of 7 to 4.
    Notes: Die Umsetzung von Perchlorbutenin (1) mit primären aliphatischen Aminen liefert die Ketenimine 3, deren Stabilität mit dem Raumbedarf der Aminogruppen zunimmt. In reiner Form sind daher nur 3e-g isolierbar. Die Hydrolyse von 3 ergibt die Säureamide 4. 4e wird weiter zu der bekannten Säure 5 hydrolysiert. - Durch Cycloaddition von Trichloracetylisocyanat an 3 und nachfolgende Tautomerisierung entstehen die 4H-1,3-Oxazin-4-one 8 in guter Ausbeute. Diese erfahren mit wäßrigem Ethanol oder absolutem Methanol eine Ringöffnung zu den substituierten Malonamiden 7 bzw. 10. Der weitere Abbau von 7 zu 4 ist konstitutionsbeweisend für die Oxazinone 8.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Synthesis of Alcohols, I. Synthesis of One-Carbon Homologous Allyl Alcohols from Aldehydes or KetonesThe high yield conversion of aldehydes and ketones 2 to the one-carbon homologous allyl alcohols 3 is achieved by condensation to the vinyl sulfoxides 7, isomerisation to the allyl sulfoxides 9, and subsequent [2,3]sigmatropic rearrangement.
    Notes: Die Umwandlung von Aldehyden und Ketonen 2 in die um ein C-Atom reicheren Allylalkohole 3 gelingt durch Umsetzung zu den Vinylsulfoxiden 7, deren Isomerisierung zu den Allylsulfoxiden 9 und nachfolgende [2,3]sigmatrope Umlagerung.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 831-844 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Synthesis of Alcohols, II. Stereochemistry of the [2,3]Sigmatropic Rearrangement of 3-Substituted 2-Alkenyl SulfoxidesRearrangement of the 3-E-substituted allyl sulfoxides 5 to the allyl alcohols 19 and 30 proceeds with low enantiomeric selectivity. In contrast, the 3-Z-substituted allyl sulfoxide 7b rearranged uniformly via the endo-transition state 26.
    Notes: Bei der Umlagerung von 3-E-substituierten Allylsulfoxiden 5 weisen die so erhaltenen Allylalkohole 19 und 30 nur geringe Enantiomerenreinheit auf. Das 3-Z-substituierte Allylsulfoxid 7b lagert dagegen einheitlich über den endo-Übergangszustand 26 um.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 934-940 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement of α-Isocyanato-N2-(arylsulfonyl)amidines to 1-Arylsulfonyl-3-imidazolin-2-onesThe reaction of the azirines 1 with the isocyanates 2 leads to the α-isocyanato-N2-(arylsulfonyl)-amidines 6. Starting from 1b, also considerable amounts of 7b and 8b are formed as a result of a retro-ene reaction of 6b. The heterocumulenes 6 readily rearrange with a shift of the sulfonyl group to give the heterocycles 10. The mobility of the sulfonyl residue is also obvious from the reaction of 6a with hydrogen chloride to afford tosyl chloride and 8a as well as from the reaction with amines, which, however, does not only yield the tosylamides 15, but also the ureas 13 and their secondary products 14.
    Notes: Die Reaktion der Azirine 1 mit den Isocyanaten 2 führt zu den α-Isocyanato-N2-(arylsulfonyl)-amidinen 6. Ausgehend von 1b werden auch beträchtliche Mengen 7b und 8b als Folge einer Retro-En-Reaktion von 6b gebildet. Die Heterocumulene 6 lagern sich unter Wanderung der Sulfonyl-Gruppe leicht in die Heterocyclen 10 um. Die Beweglichkeit des Sulfonyl-Rests wird auch in der Reaktion von 6a mit Chlorwasserstoff zu Tosylchlorid und 8a sowie in der Umsetzung mit Aminen deutlich, die neben Tosylamiden 15 allerdings auch Harnstoffe 13 und deren Folgeprodukte 14 liefert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 970-978 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Introduction of the (Dimethylhydrazono)ethyl Group into Methylene Active Compounds and PhenolsIn [2-(dimethylhydrazono)ethyl]trimethylammonium iodide the trimethylammonium group can be substituted by several nucleophiles. With this reagent (dimethylhydrazono)ethyl derivatives of CH-acidic compounds, phenols, and indole can be prepared.
    Notes: In [2-(Dimethylhydrazono)ethyl]trimethylammonium-iodid (19) läßt sich die Trimethylammoniumgruppe durch verschiedenartige Nucleophile verdrängen. CH-acide Verbindungen sowie Phenole und Indole kann man mit diesem Reagenz zu den entsprechenden Hydrazonoethyl-Derivaten umsetzen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 9-18 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydrogen Transfer Reactions, Part 2. Radical Mechanism of Thermal Disproportionation of 1,2-DihydronaphthaleneIn the thermal disproportionation of 1,2-dihydronaphthalene (1) both hydrogen abstraction and addition are stereo-unspecific radical reactions. An electrocyclic mechanism was excluded.
    Notes: Bei der thermischen Disproportionierung von 1,2-Dihydronaphthalin (1) verlaufen Wasserstoff-abspaltung und -addition als sterisch unspezifische Radikalreaktionen. Ein Synchronmechanismus wurde ausgeschlossen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1663-1690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Substituted 1,3-Butadienes in Diels-Alder-ReactionsKinetic data for the reaction of substituted 1,3-dienes with tetracyanoethylene (TCNE) and other dienophiles are interpreted in terms of the FMO-model. While the expectations are fulfilled qualitatively, the kinetic data cannot be correlated quantitatively. This shows that in Diels-Alder reactions besides HOMO-LUMO separation other factors play an important role, for instance the 1,4-distance in the diene and the conformational equilibrium cisoid ⇌ transoid of the diene. The kinetic data are in accord with a one-step mechanism of the cycloaddition reaction.
    Notes: Kinetische Daten für die Umsetzung substituierter 1,3-Diene mit Tetracyanethylen (TCNE) und anderen Dienophilen werden unter Zugrundelegung des FMO-Modells interpretiert. Während qualitativ die Erwartungen erfüllt sind, stellt man ein Versagen quantitativer Korrelationen fest. Dies zeigt, daß bei Diels-Alder-Reaktionen neben den HOMO-LUMO-Abständen weitere Faktoren eine bedeutsame Rolle spielen, z. B. der 1,4-Abstand im Dien, die Gleichgewichtslage cisoide ⇌ transoide Konformation des Diens und andere. Die kinetischen Daten stehen nicht im Widerspruch mit der Vorstellung eines konzertierten Ablaufs der Cycloadditionen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1708-1722 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopical Investigations of Indigo Dyes, XX. Thioindigo Dyes with Interrupted Peripheral ConjugationSome new thioindigo dyes with interrupted peripheral conjugation (10, 13, 24) were prepared by oxidative dimerisation of the corresponding α-thioketones. A comparison of the spectroscopic properties of these compounds with the spectral data of related dyes shows that the indigo chromophore is not weakened by interrupted peripheral conjugation. Some deviations from the expected spectroscopic behaviour are due to steric peculiarities of these compounds.
    Notes: Einige neue Thioindigo-Farbstoffe mit unterbrochener peripherer Konjugation (10, 13, 24) wurden durch oxidative Dimerisierung aus den entsprechenden α-Thioketonen dargestellt. Ein Vergleich der spektroskopischen Eigenschaften mit den Daten verwandter Farbstoffe zeigt, daß der Indigochromophor durch eine periphere Konjugationsunterbrechung nicht abgeschwächt wird. Einige Abweichungen vom erwarteten spektroskopischen Verhalten sind auf die jeweiligen sterischen Gegebenheiten zurückzuführen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1746-1753 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Linked Three-membered Rings, X. Synthesis and Mode of Formation of a Donor-Stabilized Dicyclopropenylioallyl CationAttempted coupling of chlorobis(dimethylamino)cyclopropenium perchlorate (5a) with the lithio-cyclopropenium system 6 takes a completely different course compared to the corresponding reaction of the sterically crowded analogues 5b, c. A donor-stabilized tricarbenium ion 12 is formed in place of the expected triafulvalene dication 1a. MNDO-calculations on the model compound 14 allow preliminary conclusions to be made concerning the reaction mechanism.
    Notes: Chlorbis(dimethylamino)cyclopropenylium-perchlorat (5a) zeigt beim Kupplungsversuch mit dem Lithiocyclopropenylium-System 6 ein völlig anderes Reaktionsverhalten als die sterisch gehinderten Bis(dialkylamino)cyclopropenylium-Systeme 5b, c. Anstelle des erwarteten Triafulvalen-Dikationsalzes 1a bildet sich das donorstabilisierte Tricarbenium-Ion 12. Aus MNDO-Modellrechnungen an dem Grundkörper 14 lassen sich erste Anhaltspunkte für den Mechanismus der zu diesem Trikation führenden Reaktionssequenz ableiten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1775-1789 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereospecific Synthesis of Nucleoside-5′-carboxylic Acid Derivatives with Pyrimidines as Hetero-cyclic BasePyrimidine nucleoside-5′-carboxylic acid derivatives were synthesized by condensation of riburonic acid glycosyl halides with heterocyclic bases via different methods. According to the investigations, the benzoyl-protected riburonic acid glycosyl halides 3b and 16b are valuable starting materials for the synthesis of β-nucleosides. Silver perchlorate proved to be the best catalyst in these condensation reactions with respect to stereoselectivity and yield. The methyl esters and the ethyl amides of uridine-, cytidine-, and thymidine-5′-carboxylic acid 8b, 11b, 18b, 19b and 20b were synthesized by this method stereospecifically and in good yield.
    Notes: Pyrimidinnucleosid-5′-carbonsäure-Derivate wurden durch Kondensation von Riburonsäure-glycosylhalogeniden mit heterocyclischen Basen nach verschiedenen Methoden hergestellt. Nach den Untersuchungen eignen sich als Ausgangskomponenten zur Synthese der β-Nucleoside am besten die benzoyl-geschützten Riburonsäure-glycosylhalogenide 3b und 16b. Die Verwendung von Silberperchlorat als Katalysator für die Kondensation ergab insgesamt die besten Ergebnisse bezüglich Stereoselektivität und Ausbeute. Die Methylester bzw. Ethylamide 8b, 11b, 18b, 19b und 20b der Uridin-, Cytidin- und Thymidin-5′-carbonsäure wurden auf diese Weise stereospezifisch und mit guten Ausbeuten synthetisiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Attempts to Stabilize Nitrile Sulfides at the Metal. Reactions of 5-R-1,3,4-Oxathiazol-2-ones with (Triphenylphosphane)palladium(0) and -platinum(0) Compounds: N-Thiohydroximato ComplexesOxathiazolones (1) are added oxidatively to (triphenylphosphane)platinum(0) and -palladium(0) compounds to give carbon monoxide and the complexes 2 and 3 with the dianion of N-thiohydroximic acid and its derivatives as chelating ligands. The structure of 2g was determined by x-ray analysis.
    Notes: Oxathiazolone (1) addieren sich oxidativ an (Triphenylphosphan)platin(0)- und -palladium(0)-Verbindungen unter Abspaltung von Kohlenmonoxid und Bildung der Komplexe 2 und 3 mit dem negativ zweiwertigen Anion von N-Thiohydroximsäure bzw. deren Derivate als Chelatliganden. Die Struktur von 2g wurde röntgenographisch bestimmt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1855-1866 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Benzene Derivatives with Several Homochirally-analogous SubstituentsBy cyclotrimerization of the corresponding acetylene derivatives some 1,3,5-trisubstituted benzene derivatives (2a - c, 8a, d) containing three identical chiral groups have been synthesized. The analogous mono- and 1,4-disubstituted products (6, 7) have been prepared by Grignard reactions. As chiral ligands we have used sec-butyl, (1,2,2,3-tetramethylcyclopentyl)methyl (from D-camphor), and their 1-hydroxy derivatives. In addition a few esters and ethers with chiral acids and alcohols, resp., have been prepared from phenol, hydroquinone, and phloroglucinol in the usual manner (10b, d, f, 12b).
    Notes: Durch Cyclotrimerisierung der entsprechenden Acetylenderivate wurden einige 1,3,5-trisubstituierte Benzolabkömmlinge (2a - c, 8a, d) mit drei identischen chiralen Gruppen synthetisiert. Die analogen mono- und 1,4-disubstituierten Produkte (6, 7) wurden mittels Grignard-Reaktionen dargestellt. Als chirale Liganden wurden dabei sec-Butyl, (1,2,2,3-Tetramethyl-cyclopentyl)methyl (aus D-Campher) und deren 1-Hydroxyderivate verwendet. Zusätzlich wurden einige Ester und Ether mit chiralen Säuren bzw. Alkoholen aus Phenol, Hydrochinon und Phloroglucin in üblicher Weise dargestellt (10b, d, f, 12b).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1890-1897 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXIV. Preparation and Reactions of 1,4-Diketones Containing Nitrogen GroupsThiazolium salt-catalyzed addition of aldehydes containing nitrogen groups to vinyl ketones yields 1,4-diketones (1 - 27). γ-Diketones (20, 25) thus obtained lead to the formation of carbazole derivatives (28 - 31).
    Notes: Unter Thiazoliumsalz-Katalyse addieren N-haltige Aldehyde an Vinylketone unter Bildung von 1,4-Diketonen (1 - 27). Die erhaltenen Γ-Diketone (20,25) lassen sich leicht zu Carbazolsystemen (28 - 31) umsetzen.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 43
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, XIX. Sila-Pridinol and Pridinol: Preparation and Properties as well as Structures in the Solid State and in SolutionSila-pridinol (2b), a sila-analogue of the anticholinergic pridinol (2a), was prepared by two different routes. The crystal and molecular structures of 2a and 2b were determined by X-ray structural analyses. 2a forms intramolecular hydrogen bonds in the solid state, whereas centrosymmetric cyclic dimers linked through intermolecular hydrogen bonds are observed for crystalline 2b. IR- and 1H NMR spectroscopic as well as cryoscopic studies yielded information about the structures of 2a and 2b in different solvents.  -  The pharmacological and toxicological properties of 2a and 2b were compared with one another on the basis of known structure-activity relationships. The anticholinergic properties of 2b were found to be about five times as strong as those of 2a.
    Notes: Sila-Pridinol (2b), ein Sila-Analogon des Anticholinergicums Pridinol (2a), wurde auf zwei verschiedenen Wegen dargestellt. Die Kristall- und Molekülstrukturen von 2a und 2b wurden rönt-genstrukturanalytisch bestimmt. 2a bildet im festen Zustand intramolekulare Wasserstoffbrückenbindungen aus, während sich in kristallinem 2b zentrosymmetrische, durch intermolekulare H-Brückenbindungen verknüpfte cyclische Dimere finden. IR- und 1H-NMR-spektroskopische sowie kryoskopische Untersuchungen ergaben Informationen über die Strukturen von 2a und 2b in verschiedenen Lösungsmitteln.  -  Die pharmakologischen und toxikologischen Eigenschaften von 2a und 2b wurden unter dem Gesichtspunkt bekannter Struktur-Wirkungs-Beziehungen vergleichend untersucht. 2b erwies sich als ein etwa fünfmal so starkes Anticholinergicum wie 2a.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2007-2014 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Strained Cyclic Acetylenes, VIII. Hydrogenation of Angle Strained Seven-Membered Cycloalkynes with AlcoholsThe strained seven-membered cycloalkyne 1a reacts at room temperature with methanol, 2-propanol, and benzyl alcohols, respectively, to give the alkene 2a and the corresponding carbonyl compounds. The H/D-isotope effects were investigated and a mechanism is proposed for this reaction on the basis of the rate law.
    Notes: Das gespannte Siebenring-Acetylen 1a reagiert bei Raumtemperatur mit Methanol, 2-Propanol und Benzylalkoholen; dabei werden das Alken 2a und die den Alkoholen entsprechenden Carbonylverbindungen gebildet. Die H/D-Isotopeneffekte wurden untersucht, und aufgrund des Geschwindigkeitsgesetzes wird ein Mechanismus für diese Reaktion vorgeschlagen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2031-2035 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatographie Resolutions of Racemates, IX. Chlorotalidone-, Chlorotalidone Methyl Ether-, and Oxazepam EnantiomersThe racemic drugs chlorotalidone (2a) and oxazepam (3) are completely, chlorotalidone methyl ether (2b) partially resolved by chromatography on the optically active amide 1. 2a and 3 racemize under the influence of acids and bases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2040-2042 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Aryl-3-chloro-1,2-diaziridines as Isolable Intermediates in the Preparation of 3-Aryl-3-chloro-3H-1,2-diazirinesThe formation of 3-aryl-3-chloro-3H-1,2-diazirines 3 from arylamidines 1 with sodium hypo-chlorite passes through intermediate 3-aryl-3-chloro-1,2-diaziridines 2, which are isolable at low temperature. The direct path 1 → 3 so far suggested therefore becomes unlikely.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2043-2048 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Discadenine Derivatives without Cytokinine Active Δ2-Isopentenyl ResidueAlkylation of adenine with ethyl 4-bromo-2-L-phthalimidobutyrate yields the N-3-alkylated derivative 4a. After removal of the protecting groups in 4a L-(+)-discadenine without cytokinine active N6-Δ2-isopentenyl residue (3a) is obtained. It shows similar inhibition of the spore germination as L-(+)-discadenine (1). The derivatives 3b and c with modifications in the N-3 side chain are prepared analogously. The pKa value of 5.67 implies that protonation around the physiological pH value plays a key role in the biosynthesis and the regulatory function of discadenine.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2063-2068 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Sulfur Nitrogen Boron Compounds; Crystal and Molecular Structure of an Eight-membered S—N—B Ring1,1,5,5-Tetramethyl-3,7-diphenyl-1λ6,5λ6,2,4,6,8,3,7-dithiatetrazadiborocin (4), an eight-membered ring, was synthesized by the reaction of dichlorophenylborane (3) with S,S-dimethyl-N,N′-bis(trimethylsilyl)sulfodiimide (2). The reaction of 3 with N,N′-dimethyl-N,N′-bis(trimethylsilyl)sulfamide (5) yields a polymeric compound 6. The molecular structure of 4 was determined from single crystal X-ray data and refined to an unweighted R-value of 0.079. The compound crystallizes in the orthorhombic space group Pbca. The eight-membered ring exhibits significant deviations from planarity.
    Notes: 1,1,5,5-Tetramethyl-3,7-diphenyl-1λ6, 5λ6,2,4,6,8,3,7-dithiatetrazadiborocin (4), ein achtgliedriger Ring, wurde durch Reaktion von Dichlorphenylboran (3) mit S,S-Dimethyl-N,N′-bis(trimethylsilyl)sulfodiimid (2) dargestellt. Die Umsetzung von 3 mit N,N-Dimethyl-N,N′-bis(trimethylsilyl)sulfamid (5) ergibt ein polymeres Produkt 6. Die Struktur von 4 wurde aus Diffraktometer-Einkristalldaten bestimmt und zu einem ungewichteten R-Wert von 0.079 verfeinert. 4 kristallisiert in der orthorhombischen Raumgruppe Pbca. Der Achtring zeigt erhebliche Abweichungen von der Planarität.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2086-2099 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acylation of 4-PyridoneOnly N-acyl-4-pyridones (5) are isolable from the acylation of 4-pyridone (1) with aliphatic carboxylic anhydrides, and chlorides or free acids in the presence of dicyclohexylcarbodiimide. Similarly the reaction of 1 with ortho substituted derivatives of benzoic acid leads only to N-acylation products 8, while benzoyl chloride as well as benzoic acid derivatives 7i - s (meta or para substituted), 3,5-dinitrobenzoyl chloride, and the 2,4-dimethyl substituted benzoyl chlorides 7v - z give exclusively 4-(acyloxy)pyridines 9. Reaction of phthaloyl chloride (10) with 1 yields both N- and O-acylation products. In solution even at room temperature the N-acylation compounds 2 and 8 are in equilibrium with the (acyloxy)pyridines 3 and 9, respectively. The position of the equilibrium depends mainly on the structure of the acyl residue, it is, however, also effected by temperature and polarity of the solvent.
    Notes: Bei der Acylierung von 4-Pyridon (1) mit aliphatischen Carbonsäure-anhydriden und -chloriden oder freien Säuren in Gegenwart von Dicyclohexylcarbodiimid erhält man ausschließlich N-Acyl-4-pyridone (5). Auch bei der Umsetzung von 1 mit ortho-substituierten Benzoesäurederivaten sind nur N-Acylierungsprodukte 8 isolierbar. Benzoylchlorid selbst, die meta- und para-substituierten Benzoesäurederivate 7i-s, 3,5-Dinitrobenzoylchlorid sowie die 2,6-dimethyl-substituierten Benzoylchloride 7v - z ergeben dagegen ausschließlich 4-(Acyloxy)pyridine 9. Mit Phthaloylchlorid (10) reagiert 1 sowohl unter N-als auch O-Acylierung. In Lösung stellen sich schon bei Raumtemperatur Gleichgewichte zwischen den N-Acylverbindungen 2 bzw. 8 und den (Acyloxy)pyridinen 3 bzw. 9 ein. Die Gleichgewichtslage hängt hauptsächlich von der Konstitution des Acylrestes ab, wird jedoch auch von der Polarität des Lösungsmittels und der Temperatur beeinflußt.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2120-2126 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orbital-Wechselwirkungen in „Hypostrophen“, seinen Hydro- und Homo-Derivaten. Eine photoelektronenspektroskopische UntersuchungDie Analyse der ersten Banden in den He(I)-Photoelektronen(PE)-Spektren von „Hypostrophen“ (Tetracyclo[5.3.0.02,6.03,10]deca-4,8-dien, 3) sowie seiner Tetrahydro- (1), Dihydro- (2), Homo-(4) und Bishomo-Derivate (5) beruht auf der Korrelation zwischen den Spektren von 1 bis 5 sowie dem Vergleich mit den Ergebnissen von semiempirischen Rechnungen vom MINDO/3 und SPINDO/1-Typ. Die Elektronenstruktur des ersten angeregten Zustands von 3 und syn-Tricyclo[4.2.0.02,5]octadien wird im Zusammenhang mit dem Ausbleiben einer [π2s + π2s]- Reaktion diskutiert.
    Notes: Analysis of the first bands in the He(I) photoelectron spectra of “hypostrophene” (tetracyclo[5.3.0.02,6.03,10]deca-4,8-diene, 3), its tetrahydro- (1), dihydro- (2), homo- (4), and bishomo-derivative (5) has been achieved on the basis of the correlations within the series 1 to 5 with accompanying semiempirical calculations of the MINDO/3 and SPINDO/1 type. The electronic structure of the first excited states of 3 and syn-tricyclo[4.2.0.02,5]octadiene is discussed in light of their inability to undergo [π2s + π2s] ring closure.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2183-2188 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of New Sulfur TriimidesTri-tert-butylsulfur triimide (1b) reacts with isocyanates R—NCO (R = perfluoroalkyl, sulfonyl, pentafluorosulfanyl, FSO2N=C(CF3)-) to give the corresponding di-tert-sulfur triimides (tBuN)2S(NR) (3a-d, 4a, b, 5, 6) in high yields. By the same method the bis(trimethylsilyl) derivative (Me3SiN)2S(N—CF(CF3)2) (7) is prepared.
    Notes: Tri-tert-butylschwefeltriimid (1b) reagiert mit Isocyanaten R—NCO (R = Perfluoralkyl-, Sulfonyl-, Pentafluorsulfanyl-, FSO2N=C(CF3)-) in hohen Ausbeuten zu den entsprechenden Di-tert-butylschwefeltriimiden (tBuN)2S(NR) (3a-d, 4a, b, 5, 6) und tBuNCO. Auf gleichem Wege konnte auch das Bis(trimethylsilyl)-Derivat (Me3SiN)2S(N—CF(CF3)2) (7) dargestellt werden.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2200-2210 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Metal-Metal Bonds. Trinuclear Complexes by Cleavage of Fe—Mo and Fe—W BondsIn arsenic-bridged dinuclear organometallic complexes (1) with Fe—Mo and Fe—W bonds only in a few cases the simple nucleophilic cleavage of the metal-metal bonds by organometal dimethylarsenides (2) can be achieved. In addition rearrangement and substitution reactions are observed, and the always resulting trinuclear complexes with and without metal-metal bonds are partly in equilibrium with the starting complexes. In one case rearrangement leads to an ionic compound with a Fe—W bonded cation and the Cp(CO)3Cr anion.
    Notes: Bei arsenverbrückten Organometall-Zweikernkomplexen (1) mit Fe—Mo- und Fe—W-Bindungen läßt sich mit Organometall-dimethylarseniden (2) nur in einigen Fällen die einfache nucleophile Öffnung der Metall-Metall-Bindung erzielen. Dazu werden Umlagerungs- und Substitutionsreaktionen beobachtet, und die in jedem Fall entstehenden Dreikernkomplexe mit und ohne Metall-Metall-Bindung stehen z, T. mit den Ausgangskomplexen im Gleichgewicht. In einem Falle führt Umlagerung zu einer Ionenverbindung mit einem Fe—W-verknüpften Kation und dem Cp(CO)3 Cr-Anion.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2227-2248 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Light-induced Reactions, XIV. Rules for Determining Spectra of 2,4-Cyclohexadien-1-ones2,4-Cyclohexadien-1-ones of formula types 1 to 5 (cf. Fig. 1) provide basic values and positional increments for UV and 13C NMR spectra. These parameters allow to distinguish between constitutional isomers belonging to one and the same column of the graph of Fig. 1. It has become possible, e.g., to identify clearly the constitutional isomers 6 and 8 or 12 and 14, respectively.
    Notes: 2,4-Cyclohexadien-1-one des Formeltyps 1 bis 5 (s. Abb. 1) liefern Basiswerte und Positionsinkremente für UV- und 13C-NMR-Spektren. Diese Kenndaten gestatten es, zwischen Konstitutionsisomeren zu unterscheiden, die ein und derselben Spalte des Graphen von Abb. 1 angehören. Damit ist es z. B. möglich geworden, die Konstitutionsisomeren 6 und 8 bzw. 12 und 14 sicher zu identifizieren.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2308-2310 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the Reactivity of Metal π-Complexes, XXXII. On the Reactivity of Bis(2-methylallyl)palladium and -platinum towards Tertiary PhosphanesPd(2-MeC3H4)2 (1) reacts with tricyclohexylphosphane to form (2-MeC3H4)2 PdPCy3 (3) which is fluxional in benzene solution at room temperature. The platinum complex (2-MeC3H4)2-PtP(i-Pr)3 (4), obtained from Pt(2-MeC3H4)2 (2) and triisopropylphosphane, is rigid in toluene solution up to 90°C and possesses one trihapto-(π-) and one monohapto-(σ-) bonded allylic ligand.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2291-2307 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structurally Dynamical Organometal Complexes, II. Synthesis, Structure, and Dynamics of the Complexes C5H5M(2-R′C3H4)PR3 (M=Pd, Pt)The complexes C5H5M(2-R′C3H4)(M=Pd with R′=Me, t-Bu; M=Pt with R′=Me) react with an equimolar amount of PR3 (PR3=P(i-Pr)3, P(i-Bu)3, PPh2 (t-Bu), PCy3, PPhCy2) to form the compounds C5H5M(2-R′C3H4)PR3. The 1H and 13C NMR spectra indicate that in the complexes C5H5Pd(2-t-BuC3H4)PR3 and C5H5Pt(2-MeC3H4)PR3 within the temperature range of - 60 to +60°C the cyclopentadienyl ligand is monohapto-(σ-)and the allylic ligand trihapto-(π-)bonded. The complexes C5H5Pd(2-MeC3H4)PR3 exist in solution as a mixture of two isomers, (h5-C5H5)Pd(h1-allyl)PR3 (A) and (h1-C5H5)Pd(h3-allyl)PR3 (B). For complex 14 (PR3=PPhCy2) the thermodynamic and kinetic data of the intramolecular isomerisation process A ⇌ B have been determined. The X-ray structural analysis of 5 proves that the monohapto coordination of the C5H5 and the trihapto coordination of the 2-t-BuC3H4 ligand is retained in the crystal.
    Notes: Die Komplexe C5H5M(2-R′C3H4) (M=Pd mit R′=Me, t-Bu; M=Pt mit R′=Me) reagieren mit einer äquimolaren Menge PR3 (PR3=P(i-Pr)3, P(i-Bu)3, PPh2(t-Bu), PCy3, PPhCy2) zu den Verbindungen C5H5M(2-R′C3H4)PR3. Die 1H- und 13C-NMR-Spektren weisen daraufhin, daß in den Komplexen C(5H5Pd(2-t-BuC3H4)PR3 und C5H5Pt(2-MeC3H4)PR3 im Temperaturbereich von -60 bis +60°C der Cyclopentadienylligand monohapto- (σ-) und der Allylligand trihapto- (π-) gebunden ist. Die Komplexe C5H5Pd(2-MeC3H4)PR3 liegen in Lösung als Isomerengemisch von (h5-C5H5)Pd(h1-allyl)PR3 (A) und (h1-C5H5)Pd(h3-ally)PR3 (B) vor. Für 14 (PR3=PPhCy2) werden die thermodynamischen und kinetischen Daten der intramolekularen Isomerisierung A ⇌ B ermittelt. Die Röntgenstrukturanalyse zeigt, daß in 5 auch im Kristall der C5H5-monohapto- und der 2-t-BuC3H4-Ligand trihapto-koordiniert sind.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2333-2341 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidation of Diborane(4) Molecules by ChloraminesThe boron-boron bonds in the diborane(4) molecules (Me2N)2B—Clb(NMe2)2 (1), (Me2N)ClB—BCl(NMe2) (5) and Cl2B—BCl2 (8) as in B4Cl4 are cleaved by the chloramines Me2NCl (2), MeNCl2 and EtNCl2 (9). As oxidation products BCl3 or the corresponding aminoborane and diborylamines can be isolated. The interaction of 8 and 2 leads to the formation of Me2NH · BCl3 as additional product. - Elementary chlorine does not only cleave the B—B but also the B—N bond in 1, giving Me2NCl as one of the reaction products. - The properties of the N-ethylbis(dichloroboryl)amine (11) are discussed.
    Notes: Die Bor-Bor-Bindungen in den Diboran(4)-Molekülen (Me2N)2B—B(NMe2)2 (1), (Me2N)ClB—BCl(NMe2) (5) und Cl2B—BCl2 (8) wie auch in B4Cl4 werden durch die Chloramine Me2NCl (2), MeNCl2 und EtNCl2 (9) gespalten. Als Oxidationsprodukte lassen sich BCl3 oder das entsprechende Aminoboran und Diborylamine isolieren. Die Umsetzung von 8 und 2 führt zusätzlich zur Bildung von Me2NH · BCl3. - Elementares Chlor spaltet in 1 nicht nur die B—B-sondern auch die B—N-Bindung; Me2NCl ist eines der Reaktionsprodukte. - Die Eigenschaften des N-Ethylbis(dichlorboryl)amins (11) werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2358-2371 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophanes, XIII. On the Chemical Behaviour of [2.2.2](1,2,4)Cyclophane[2.2.2](1,2,4)Cyclophane (10) has been prepared by several routes from dimethyl [2.2]paracyclophane-4,13-dicarboxylate (5) and subjected to the following reactions: pyrolysis in p-diisopropylbenzene and dimethyl maleate (formation of 13 and 16, respectively), isomerization in the presence of aluminiumtrichloride/hydrogenchloride to the unsymmetrical [2.2.2](1,2,4)(1,2,5)cyclophane (17), bromination to afford 20, catalytic hydrogenation to the di- and monoolefin 22 and 23, respectively, Diels-Alder-addition with N-phenyltriazolindione, tetracyanoethylene, dicyanoacetylene, and maleic anhydride which provides 1:1- (29) and 1:2-adducts (30). The relation between chemical reactivity and degree of bridging in multiply-bridged cyclophanes is discussed.
    Notes: [2.2.2](1,2,4)Cyclophan (10) wird auf mehreren Wegen aus [2.2]Paracyclophan-4,13-dicarbonsäure-dimethylester (5) hergestellt und in folgenden Reaktionen untersucht: Pyrolyse in p-Diisopropylbenzol und Maleinsäure-dimethylester (Bildung von 13 bzw. 16), Isomerisierung in Gegenwart von Aluminiumtrichlorid/Chlorwasserstoff zum unsymmetrischen [2.2.2](1,2,4)(1,2,5)Cyclophan (17), Bromierung zu 20, katalytische Hydrierung zum Di- bzw. Monoolefin 22 und 23, Diels-Alder-Addition mit N-Phenyltriazolindion, Tetracyanethylen, Dicyanacetylen und Maleinsäureanhydrid, wobei 1:1- (29) und 1:2-Addukte (30) isoliert werden. Der Zusammenhang von Überbrückungsgrad und chemischer Reaktivität mehrfach verbrückter Phane wird diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2398-2409 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ring Strain of Cycloalkynes and its Spectroscopic ConsequencesThe enthalpies of formation ΔHf and geometrical strain energies Eg. Sp. of cyclooctyne (1) and the three isomeric cyclooctenynes 5-7 are calculated with the MINDO/2-method on the basis of complete geometry optimizations. The frequencies of the C≡C-stretching vibrations (fig. 4) and the 13C-shifts of the acetylenic carbon atoms (fig. 6) obey quantitative correlations, which are very useful for the evaluation of geometrical ring strains.
    Notes: Bildungsenthalpien ΔHf und geometrische Ringspannungen Eg. Sp. für Cyclooctin (1) und die drei isomeren Cyclooctenine 5-7 werden nach der MINDO/2-Methode auf der Basis vollständiger Geometrie-Optimierungen berechnet. Mit den Frequenzen der C≡C-Valenzschwingungen (Abb. 4) und mit den 13C-Verschiebungswerten der acetylenischen Kohlenstoffatome (Abb. 6) ergeben sich quantitative Korrelationen, die zur Abschätzung von geometrischen Ringspannungen von großem Wert sind.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2490-2498 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement Reactions of 2-Alkyl(Aryl)-3-arylimino-1,2-benzisothiazolines3-Chloro-1,2-benzisothiazolium chlorides 1 react with aromatic amines to give the 2-substituted 3-arylimino-1,2-benzisothiazolines 2 which can rearrange to the isomeric 1,2-benzisothiazolines 3 in an equilibrium reaction. On a formal basis this entails an exchange of positions of the substituents (R1 and R2) on the ring and exo nitrogen atoms. The nature of the substituents R1 and R2 is decisive for the position of equilibrium and the rapidity with which it is reached.
    Notes: 3-Chlor-1,2-benzisothiazolium-chloride 1 reagieren mit aromatischen Aminen zu den 2-substituierten 3-Arylimino-1,2-benzisothiazolinen 2, die sich in einer Gleichgewichtsreaktion in die isomeren 1,2-Benzisothiazoline 3 umlagern können. Dieses ergibt formal einen Platzwechsel der Substituenten (R1 u. R2) am Ring- bzw. exocyclischen Stickstoffatom. Die Lage dieses Gleichgewichtes und die Geschwindigkeit seiner Einstellung hängen entscheidend von der Art der Substituenten R1 und R2 ab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2311-2313 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Anomalous Reaction of a 3-Chloro-2-nitroanisoleDuring the synthesis of 8-chloro-1,5-dihydro-5-hydroxy-1-phenyl-2H-1,5-benzodiazepine-2,4 (3H)-dione (4) 3,5-dichloro-2-nitroanisole (B) reacts with aniline under cleavage of the etherlinkage to form 5-chloro-3-hydroxy-2-nitrodiphenylamine (1).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2318-2322 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatographie Resolutions of Racemates, X. Optical Resolutions of Thalidomide and Other Glutarimide DerivativesRacem. thalidomide (1a) is resolved completely by chromatography on the chiral polyamide 2e in an analytical as well as preparative scale. The glutarimides 1b - d are partially resolved. Both enantiomers of 1b and one enantiomer of 1d were isolated by recycling chromatography.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2326-2331 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions with Organophosphorus Compounds, XLV. A New Synthesis of (2-Oxocycloalkylidene)triphenylphosphoranesThe bromoenolethers 1, upon treatment with triphenylphosphane in nitromethane, yield the cycloalkenylphosphonium salts 4, which on subsequent reaction with hydrochloric acid and sodium carbonate afford the (2-oxocycloalkylidene)phosphoranes 3. With methyl bromide the O-methyl derivatives 4 are reformed from compounds 3; with acetyl azide the condensed acyltriazoles 5 are obtained, which lead to the unsubstituted triazoles 6, when treated with KOH. Reaction of 3b with (SCN)2 yields the cycloheptene derivative 7b, which can be cyclized to the thiazole 8b.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2323-2325 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Chiral Rhodium(I) Complex of (2R,3R)-2,3-Bis(diphenylphosphino)butane for Asymmetric HydrogenationsRhodium(I) complexes of the new chiral ligand (2R,3R)-2,3-bis(diphenylphosphino)butane (4)  -  which is easily prepared from natural tartaric acid  -  hydrogenate α-(acylamino)acrylic acids to natural (S)-acylamino acids in high chemical (95 - 100%) and optical (80 - 100%) yields.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2342-2347 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel 1,3,5,7-Tetraaza-2,4,6,8-tetrasilabicyclo[4.2.0]octaneThe reaction of mono- and dilithio-2,2,4,4,6,6-hexamethylcyclotrisilazane (1, 2) with aminofluorosilanes R—SiF2—NR′SiMe3 (R=F, Me; R′=CMe3, SiMe3) leads to LiF elimination and formation of the cyclotrisilazanes 3-5. The cyclodisilazane 6 is obtained by ring contraction in the reaction of compound 5 with butyllithium and F3SiN(CMe3)(SiMe3). The lithium salt of 5 forms the novel title compound 7 by an intramolecular reaction with LiF- elimination, silyl group and methanide ion migration. Another bicyclic compound 8 is obtained in the reaction of 2 with C4H9Li and F2SiMeN(SiMe3)2. The reaction mechanism is discussed.
    Notes: Mono- und dilithiiertes 2,2,4,4,6,6-Hexamethylcyclotrisilazan (1, 2) reagieren mit Aminofluorsilanen des Typs R—SiF2—NR′SiMe3 (R=F, Me; R′=CMe3, SiMe3) unter LiF-Abspaltung zu den Cyclotrisilazanen 3-5.5 reagiert mit Butyllithium und F3SiN(CMe3)(SiMe3) unter Ringkontraktion zum Cyclodisilazan 6. Intramolekular bildet das Lithiumsalz von 5 unter LiF-Abspaltung, Silylgruppen- und Methanid-Ionen-Wanderung die neuartige Titelverbindung 7. Ein weiterer Bicyclus (8) entsteht bei der Umsetzung von 2 mit C4H9Li und Me—SiF2—N(SiMe3)2. Der Bildungsmechanismus wird diskutiert.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2383-2397 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of CyclooctenynesThe three isomeric cis-cyclooctenynes 2-4 are prepared. The ring strain is enhanced in comparison to cyclooctyne (1) and increases from 1 to 4. The resulting consequences on life time and reactivity of the compounds are discussed.
    Notes: Die drei strukturisomeren cis-Cyclooctenine 2-4 werden dargestellt. Im Vergleich zu Cyclooctin (1) ist die Ringspannung dieser Systeme erhöht: sie wächst in der Reihenfolge 1, 2, 3, 4. Die sich daraus ergebenden Auswirkungen auf die Lebensdauer und Reaktivität der Verbindungen werden diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2410-2423 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 272. On the Constituents of Zexmenia gnaphaloides and the Synthesis of Valerenane DerivativesThe investigation of a Mexican Zexmenia species afforded in addition to known compounds three new eudesmanolides (9-11) as well as five sesquiterpenes (31b, c, 33, 34a, b), the stereochemistry of which could not be established directly. Therefore the main compound 31c has been synthesized. By intramolecular diene synthesis the preparation of a suitable tetrahydroindane (19) was possible. From this, three of the possible four stereoisomeric aldehydes (23c, 24c, 30c) have been prepared. While one of the obtained aldehydes could be transformed into the compound isolated from the Zexmenia species (31c, obtained as ester 31a), the second one yielded valerenal (25c), one of the constituents of Valeriana officinalis. The thermodynamically most stable isomeric aldehyde 24c surprisingly is formed already under very mild conditions from both other aldehydes 23c and 30c.
    Notes: Die Untersuchung einer mexikanischen Zexmenia-Art ergibt neben bekannten Verbindungen drei neue Eudesmanolide (9-11), sowie fünf Sesquiterpene (31b, c, 33, 34a, b), deren Stereochemie nicht eindeutig geklärt werden konnte. Der Hauptvertreter 31c wurde daher synthetisch dargestellt. Durch intramolekulare Diensynthese gelingt die Darstellung eines geeigneten Tetrahydroindan-Derivates (19). Daraus wurden von vier möglichen stereoisomeren Aldehyden drei dargestellt (23c, 24c, 30c). Während einer der erhaltenen Aldehyde in die aus der Zexmenia-Art isolierten Verbindung 31c (als Ester 31a) übergeführt werden konnte, liefert der zweite Valerenal (25c), einen der Inhaltsstoffe aus Valeriana officinalis. Der thermodynamisch stabilste Aldehyd 24c entsteht überraschenderweise durch Isomerisierung aus beiden anderen Isomeren 23c und 30c bereits unter sehr milden Bedingungen.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2424-2429 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Influence of Substrate Micellisation on the Rate of Solvolysis of 1-Methylheptyl Methanesulfonate in Dioxane-WaterThe solvolysis rate of 1-methylheptyl mesylate in 25% dioxane-75% H2O was conductometrically determined at 35°C for varying substrate concentrations (c0 = 0.002-0.08 mol/l). The rate constant decreased with increasing concentration in a manner typical of substrate micellisation above the cmc. A phase diagram shows that in this range of concentration the system is passing from the one phase into the two phase region. The implications of this observation for the experimental background of the ion-pair SN2-mechanism proposed by Sneen in 1969 are discussed.
    Notes: Die konduktometrisch bei 35°C bestimmte Solvolysekonstante von 1-Methylheptyl-methansulfonat in 25% Dioxan-75% Wasser sinkt mit steigender Substratkonzentration (c0 = 0.002-0.08 mol/l). Ein Phasendiagramm zeigt, daß in diesem Konzentrationsbereich der Übergang vom einphasigen in den zweiphasigen Bereich erfolgt. Die Bedeutung dieser Beobachtung für die experimentellen Grundlagen des von Sneen 1969 vorgeschlagenen Ionenpaar-SN2-Mechanismus wird diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 68
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Substituted Phosphanes, Arsanes, and Stibanes, XXII. Synthesis, Mechanism of Formation, and Molecular Structure of a Bis(organometal)dimethylarsonium MetalateThe interaction of the transition metal arsanes C5H5(CO)2PMe3M—AsMe2 and C5H5(CO)3M—AsMe2 gives the bismetalarsonium metalates {[C5H5(CO)2PMe3M]2AsMe2}{M(CO)3C5H5} (1a (Mo), 1b (W)) and tetramethyldiarsane. 1a is rapidly converted into {[C5H5(CO)2PMe3Mo]2AsMe2}I (2) and MeMo(CO)3C5H5 by MeI. The structure of the bismetalarsonium salts is proved by IR and NMR spectra and an X-ray analysis of 1a. Their mechanism of formation is discussed.
    Notes: Die Umsetzung der Übergangsmetallarsane C5H5(CO)2PMe3M—AsMe2 und C5H5(CO)3M—AsMe2 ergibt die Bismetallarsonium-metallate {[C5H5(CO)2PMe3M]2AsMe2}{M(CO)3C5HJ} (1a (Mo), 1b (W)) und Tetramethyldiarsan. 1a wird durch MeI rasch in {[C5H5(CO)2PMe3Mo]2AsMe2}I (2) und MeMo(CO)3C5H5 umgewandelt. Die Konstitution der Bismetallarsoniumsalze wird durch IR-und NMR-Spektren sowie eine Röntgenstrukturanalyse von 1a belegt. Es wird ein Mechanismus für ihre Bildung diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2739-2748 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclopolyaromatics, IX1). 4,4‴,6,6‴-Tetraazahexa-m-phenylene and 4,4′,4‴,4′‴,6,6′,6‴,6′‴-Octaazahexa-m-phenyleneThe synthesis of the title compounds 4 and 9 is described. In contrast to hexa-m-phenylene (6) 4,4‴,6,6‴-tetraazahexa-m-phenylene (4) is planar. This is explained by less Pitzer strain in the outer sphere of 4. From 4 a tetranitro derivative (7c) was obtained.
    Notes: Die Synthese der Titelverbindungen 4 und 9 wird beschrieben. Im Gegensatz zum bekannten Hexa-m-phenylen (6) ist 4,4‴,6,6‴-Tetraazahexa-m-phenylen (4) planar. Dies wird auf geringere Pitzer-Spannung in der äußeren Sphäre von 4 zurückgeführt. Von 4 wurde eine Tetranitroverbindung (7c) erhalten.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2755-2759 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclopolyaromatics, XI. Synthesis, Lithiation, and Oxidative Coupling of 1,3,5-Tri(1-pyrazolyl)benzeneThe title compound 3b, prepared from 1,3,5-tribromobenzene and pyrazole (90%), has been monolithiated at the benzene ring by 1 mol n-butyllithium quantitatively. Oxidative coupling of fivefold lithiated 3b with O2 afforded a disubstituted cyclohexaaromatic compound 4b (3.5%) with face-to-face arrangement of two benzene rings besides the dehydrodimer 4a (8%).
    Notes: Die Titelverbindung 3b, dargestellt aus 1,3,5-Tribrombenzol und Pyrazol (90%), wird durch 1 mol n-Butyllithium quantitativ am Benzolring monolithiiert. Fünffach lithiiertes 3b gibt bei der oxidativen Kupplung mit Sauerstoff den disubstituierten Cyclohexaaromaten 4b (3.5%) mit face-to-face-Anordnung von zwei Benzolringen neben dem Dehydrodimeren 4a (8%).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2530-2544 
    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 5′-Deoxynucleoside 5′-Carboxylic Acids and DerivativesA preparative route to 5′-deoxynucleosid- 5′-carbonitriles (3), both of the ribose and deoxyribose series, involves crown ether-catalyzed reaction of nucleoside 5′-tosylates with solid potassium cyanide in organic solvents. O2,5′-Cyclo derivatives of pyrimidine nucleosides can also serve as starting materials. The nitriles 3 require acidic conditions for conversion to the esters 6 of 5′-deoxynucleoside 5′-carboxylic acids (7) which are suitable nucleotide models for biochemical studies. In alkaline solutions compounds 3 undergo rapid elimination of the purine or pyrimidine base. Furthermore the adenine derivative 3a, under addition of the unsaturated sugar fragment 10 yields a new nucleoside 12 in which N6 is inserted in a pyrrolidine ring. The circular dichroism spectra of the new compounds reflect strong electronic interaction between polar C-5′-substituents and the chromophores and are in line with those of other C-5′-modified nucleosides.
    Notes: Die Darstellung von bisher nicht allgemein zugänglichen 5′-Desoxynucleosid-5′-carbonitrilen (3) gelingt sowohl in der Ribo- wie 2′-Desoxyribonucleosidreihe, wenn man Nucleosid-5′-tosylate mit festem KCN unter Kronenether-Katalyse in organischen Lösungsmitteln umsetzt. Auch O2, 5′-Cyclopyrimidinnucleoside eignen sich als Ausgangsmaterial. Aus den Nitrilen 3 sind unter vorzugsweise sauren Reaktionsbedingungen die Ester 6 und aus ihnen die 5′-Desoxynucleosid-5′-carbonsäuren (7) erhältlich, die sich als Nucleotid-Modelle in biochemischen Systemen eignen. In alkalischer Lösung erleiden die Nitrile 3 rasche Eliminierung der Purin- oder Pyrimidinbase. Aus dem Adeninnucleosid 3a entsteht dabei ferner unter Addition des ungesättigten Zuckerfragmentes 10 das an N6 zu einem Pyrrolidin modifizierte Nucleosid 12. Wie in anderen C-5′-modifizierten Nucleosiden zeigen die Circulardichroismus-Spektren der neuen Verbindungen eine starke elektronische Wechselwirkung zwischen polaren C-5′-Substituenten und den Chromophoren an.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2566-2574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemistry of Heterocycles, 8. The Photoreaction of 2,5-Diaryl-1,3,4-oxadiazoles with 1,3-Dimethyluracils. A New and Simple Synthesis of 1,2,4,5-TetrazinesUpon UV-irradiation 2,5-diaryl-1,3,4-oxadiazoles 2a-g do not undergo (2 + 2)-cycloaddition with 1,3-dimethyluracil, but instead ring cleavage occurs to afford the benzoylhydrazones 3a-e as well as the decomposition products 4-6. With 6-chloro-1,3-dimethyluracil (1b) 3h is formed, which in turn photoeliminates benzoyl chloride to give the pyrazolo[3,4-d] pyrimidine 7. Saponification of 3a gives smoothly 5-benzoyl-1,3-dimethyluracil (photoselective 5-benzoylation). - A new and simple synthesis of 3,6-disubstituted 1,2,4,5-tetrazines from aroylhydrazines is described, employing the system triphenylphosphane/hexachloroethane/triethylamine.
    Notes: Die 2,5-Diaryl-1,3,4-oxadiazole 2a-g reagieren bei UV-Bestrahlung mit 1,3-Dimethyluracil nicht unter (2 + 2)-Cycloaddition sondern unter Ringspaltung von 2a-g zu den Benzoylhydrazonen 3a-e und deren Zersetzungsprodukten 4-6. Mit 6-Chlor-1,3-dimethyluracil (1b) entsteht-via Hydrazon 3h-unter Photoeliminierung von Benzoylchlorid das Pyrazolo[3,4-d]pyrimidin 7. Durch Verseifung von 3a ist 5-Benzoyl-1,3-dimethyluracil leicht zugänglich (photoselektive 5-Benzoylierung). - Eine neue und einfache Synthese von 3,6-disubstituierten 1,2,4,5-Tetrazinen aus Aroylhydrazinen und dem System Triphenylphosphan/Hexachlorethan/Triethylamin wird beschrieben.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2609-2615 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conformational Analysis, XXII. Twist-Boat Conformation of Methyl 2,3,4-Tri-O-benzoyl-β-D-xylopyranoside in the CrystalMethyl 2,3,4-tri-O-benzoyl-β-D-xylopyranoside (5) crystallizes in the monoclinic space group P21 with two molecules in the asymmetric unit. Structure analysis (R-value 0.044) reveals that in the crystal 5 is present in a twist-boat conformation 2So in which the atoms C1, C3, C4, C5 and O5, C1, C2, C4 lie in one plane. In solution, 5 shows an equilibrium of the chair conformations with a proportion of 26% of the 1C4-form.
    Notes: Methyl-2,3,4-tri-O-benzoyl-β-D-xylopyranosid (5) kristallisiert in der monoklinen Raumgruppe P21 mit 2 Molekülen in der asymmetrischen Einheit. Die Strukturanalyse (R-Wert 0.044) ergibt, daß 5 im Kristall in einer Twist-Boat-Konformation 2So vorliegt, bei der die Atome C1, C3, C4, C5 und O5, C1, C2, C4 in einer Ebene liegen. In Lösung weist 5 ein Konformerengleichgewicht der Sesselformen mit einem Anteil von 26% 1C4-Form auf.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2675-2685 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of Metal-Metal Bonds. Formation and Fragmentation of Simple Dinuclear Metal-Carbonyl Complexes as an Equilibrium ReactionBy combination of the 17-electron carbonylmetal units Cp(CO)3Cr, Cp(CO)3Mo, Cp(CO)3W, (CO)5Mn, Cp(CO)2Fe, (CO)4Co, and Cp(CO)Ni the seven homonuclear as well as 21 heteronuclear dimetal complexes with metal-metal bonds can be conceived. All these heterodinuclear complexes are formed in benzene solution from mixtures of the corresponding homodinuclear compounds. The eight hitherto unreported and all known heterodinuclear complexes are thus accessible more simply than with the previously used procedures. The reactions lead to equilibrium mixtures which result equally from the two homodinuclear as well as from the heterodinuclear complexes. Upon participation of the units Cp(CO)3Cr, (CO)4Co, and Cp(CO)Ni the equilibria with three exceptions ly completely on the side of the mixed compounds. The equilibration reaction found here is of elementary importance for the chemistry of metal-metal bonds.
    Notes: Durch Kombination der 17-Elektronen-Metallcarbonyl-Bausteine Cp(CO)3Cr, Cp(CO)3Mo, Cp(CO)3 W, (CO)5Mn, Cp(CO)2Fe, (CO)4Co und Cp(CO)Ni sind die sieben bekannten homonuclearen sowie 21 heteronucleare Zweikernkomplexe mit Metall-Metall-Bindung denkbar. Alle diese heterodinuclearen Komplexe entstehen in benzolischer Lösung aus Mischungen der entsprechen den homodinuclearen Verbindungen. Die acht bisher nicht beschriebenen und alle bekannten Hetero-Zweikernkomplexe sind so leichter zugänglich als mit den bisher verwendeten Verfahren. Die Reaktionen führen zu Gleichgewichtsgemischen, die in gleicher Weise von den zwei homodinuclearen wie von den reinen heterodinuclearen Komplexen aus erreicht werden. Bei Beteiligung der Bausteine Cp(CO)3Cr, (CO)4Co und Cp(CO)Ni liegen die Gleichgewichte mit drei Ausnahmen vollständig auf der Seite der gemischten Verbindungen. Die aufgefundene Äquilibrierungsreaktion ist von prinzipieller Bedeutung für die Chemie der Metall-Metall-Bindungen.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (±)-20-Methylpregn-4-en-3 -one and (±)-20-Methyl-14β, 17α-pregn-4-en-3 -one via Ionic Cyclization of a Tetraenol with Preformed „Ring C“The acid catalyzed cyclization of the polyolefinic substrates II and III was investigated. Only tetraenol II could be induced to undergo twofold bond formation to produce the A-nor-pregna-3(5),8(14)-diene derivatives 11a/11b, epimeric at C-17. The cyclization substrate was synthesized, involving coupling (Li/THF) of diacetal bromide 4 with cyclohexenone derivative 5 followed by dehydration, ketal hydrolysis, cyclodehydration (6 → 9) and treatment of 9 with CH3Li to give the isomers 10a-c. Cyclization (CF3CO2H/CH2Cl2) of 10a-c at -80°C produced the tetracyclic dienes 11a/11b in the ratio 6:1, at 0°C in the ratio 3:2. Hydrogenation at Δ20(22) of 11a and 11b, HBr induced isomerization (Δ8(14) → Δ14) and stereoselective hydrogenation at Δ14 produced the mono-enes 16a and 16b, respectively, which were converted into the title compounds 18a and 18b.
    Notes: Es wurde die säurekatalysierte Cyclisierung der polyolefinischen Edukte II und III untersucht. Nur mit dem Tetraenol II (10a) ließ sich eine zweifache Bindungsschließung zu den 17-epimeren A-Nor-pregna-3(5),8(14)-dien-Derivaten 11a/11b bewirken. Zur Darstellung des Cyclisierungsedukts wurde das Diacetalbromid 4 mit dem Cyclohexenon-Derivat 5 zu 6 umgesetzt (Li/THF), aus dem durch Dehydratisierung, Acetalspaltung, Aldolkondensation (6 → 9) und Reaktion von 9 mit CH3Li die Isomeren 10a-c erhalten wurden. Cyclisierung (CF3CO2H/CH2Cl2) von 10a-c bei -80°C lieferte die tetracyclischen Diene 11a/11b im Verhältnis 6:1, bei 0°C im Verhältnis 3:2. Aus 11a bzw. 11b wurden durch Δ20(22)-Hydrierung, HBr-induzierte Δ8(14) → Δ14-Isomerisierung und stereoselektive Δ14-Hydrierung die Mono-ene 16a/16b erhalten und aus diesen die Titelverbindungen 18a und 18b.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2779-2786 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Small Rings, 31. Neighbouring Group Effects in Cyclobutene DerivativesBenzoylcyclobutenecarboxylic acid 6, formed as an intermediate from anhydride 2 under Friedel-Crafts conditions, adds one molecule of benzene to the formally isolated double bound. Main product is compound 5a, a minor component is stereoisomer 5b. This high selectivity can be explained by a neighbouring group relationship between double bound and benzoyl group in the cyclobutene derivative 6.
    Notes: Die aus Anhydrid 2 unter Friedel-Crafts-Bedingungen intermediär entstehende Benzoylcyclobutencarbonsäure 6 addiert ein Molekül Benzol an die formal isolierte Doppelbindung. Hauptprodukt ist Verbindung 5a, Nebenprodukt das Stereoisomere 5b. Eine Erklärung für die hohe Selektivität bietet eine Nachbargruppen-Wechselwirkung zwischen Doppelbindung und Benzoylgruppe im Cyclobuten-Derivat 6.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2760-2768 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Research on Glycoside Synthesis, XI. Preparation and Properties of AcylorthoestersCompounds with an acylorthoester structure 10a-e are prepared from 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide and silver salts of carboxylic acids in tetrahydrofuran. Compound 10e with a 4-(4-biphenylyl)butyryl residue proved to be relatively stable above all. Substances of this type could be detected also as intermediates in the Koenigs-Knorr synthesis in the presence of silver salts of carboxylic acids. In the usual working up procedure of this reaction in the presence of water they are transformed into the hydroxy sugars 15a and b. With alcohols in a slow reaction the corresponding orthoesters 11 are formed. Acylorthoesters have been postulated by Winstein and his group7) as intermediates in reactions with neighbouring group participation. The reactivity found in our experiments corresponds far reaching to that proposed before. So 10e on heating is quantitatively transformed with trans-opening of the dioxolane ring into the trans-diacyl compound 9b. In the presence of strong acids in addition a cis-opening to 15c is possible.
    Notes: Aus 2,3,4,6-Tetra-O-acetyl-α-D-glucopyranosylbromid und Silbersalzen von Carbonsäuren werden in Tetrahydrofuran Verbindungen mit einer Acylorthoester-Struktur 10a-e dargestellt. Als relativ stabil erwies sich vor allem die Verbindung 10e mit einem 4-(4-Biphenylyl)butyryl-Rest. Substanzen von diesem Strukturtyp wurden auch als Zwischenprodukte bei der Koenigs-Knorr-Synthese in Gegenwart von Silbersalzen von Carbonsäuren nachgewiesen; sie gehen bei der üblichen Aufarbeitung in Gegenwart von Wasser in die Hydroxyzucker 15a und b über. Mit Alkoholen bilden sich in langsamer Reaktion die entsprechenden Orthoester 11. Unsere Befunde stützen auch den von Winstein et al.7) bei Reaktionen unter Nachbargruppenbeteiligung postulierten Weg über Acylorthoester. So geht 10e beim Erhitzen quantitativ unter trans-Öffnung des Dioxolan Ringes in die trans-Diacylverbindung 9b über, während in Gegenwart starker Säuren auch ein cis-Öffnungsprodukt 15c entstehen kann.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2796-2801 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Hydroxyimino)ethylidene Derivatives of CH-acidic Compounds by Reaction with Dichloroacetaldehyde OximeCH-acidic compounds react with dichloroacetaldehyde oxime (15) and piperidinium acetate to give (hydroxyimino)ethylidene derivatives 20. Compounds like 2-formylcyclohexanone react thereby under elimination of the formyl group. The same products are available from enamines and 15.
    Notes: CH-acide Verbindungen lassen sich mit Dichloracetaldehyd-oxim (15) und Piperidinium-acetat zu (Hydroxyimino)ethyliden-Derivaten 20 umsetzen. Verbindungen wie 2-Formylcyclohexanon reagieren dabei unter Abspaltung der Formylgruppe. Aus Enaminen und 15 erhält man die gleichen Produkte.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Derivatives of Dithiocarbazic Acid as Ligands in Carbonyl Complexes of Manganese(I) and Rhenium(I).The Structures of Tricarbonylbis(S-methyldithiocarbazato)manganese(I) Bromide and Bis-μ-(N-isopropylidene-S-methyldithiocarbazato)-bis(tricarbonylmanganese(I))Ionic carbonyl complexes 3a, b, 4a, b are formed by the reaction of M(CO)5Br, M=Mn, Re, with S-methyl dithiocarbazate (2) in acid or neutral solutions. In alcaline solutions neutral complexes 5, 6 with the deprotonated ligand [NH2NCS2CH3]- or with its related Schiffbase anion [(CH3)2CNNCS2CH3]- (7) have been obtained. The structures of the two title compounds 3a and 7 have been determined by single crystal X-ray methods. The [Mn(CO)3 (NH2NHCS2CH3)2]+ ion contains one ligand coordinated as a chelate through N and S, in addition to a monodentate ligand, acting as N donor. The centrosymmetric dimer [Mn(CO)3 ((CH3)2CNNCS2CH3)]2 (7) contains a four-membered Mn2S2 core.
    Notes: Bei der Reaktion von Dithiocarbazinsäure-S-methylester (2) mit M(CO)5Br, M=Mn, Re, bilden sich in saurer oder neutraler Lösung ionische Carbonylkomplexe 3a, b, 4a, b. In alkalischem Medium entstehen Komplexe 5, 6 des deprotonierten Liganden [NH2NCS2CH3]-, oder nach Reaktion des Liganden mit Aceton der Komplex 7 der daraus abgeleiteten Schiffschen Base. Die Strukturen der Titelverbindungen 3a und 7 wurden röntgenographisch bestimmt. Das [Mn(CO)3(NH2NHCS2CH3)2]+-Ion enthält gleichzeitig einen chelatartig über N und S sowie einen monodentat über N gebundenen neutralen Liganden. [Mn(CO)3((CH3)2CNNCS2CH3)]2 (7) ist dimer und enthält einen Mn2S2-Vierring.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 82
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Unusual Course of the Reaction of α-Acyl-γ-butyrolactones with 2-(2,6-Dihalogenophenylimino)imidazolidinesHeating of α-acyl-γ-butyrolactones 1 with 2-(2,6-dihalogenophenylimino)imidazolidines 5 in HMPT unexpectedly leads to 7-halogeno-2-,6-dihydro-4-alkyl-5,6-ethano-1H- [1,4]diazepino-[1,7-a]benzimidazoles 7 in low yields. The structures of 7 are derived from spectroscopic data, oxidative degradation to benzimidazole derivative 9 and an X-ray structure analysis. A possible pathway for the formation of 7 is discussed.
    Notes: α-Acyl-γ-butyrolactone 1 liefern beim Erhitzen mit 2-(2,6-Dihalogenphenylimino)imidazolidinen 5 in HMPT unerwartet in geringen Ausbeuten 7-Halogen-2,6-dihydro-4-alkyl-5-,6-ethano-1H-[1,4]diazepino[1,7-a]benzimidazole 7, deren Struktur durch die spektroskopischen Daten, Abbauversuche und eine Röntgenstrukturanalyse abgeleitet wird. Der mögliche Bildungsweg dieser Verbindungen wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Complex Ligands, XVII. Regiospecific Reaction of 1,4-Enynes with Pentacarbonyl(methoxyphenylcarbene)chromium(0): Preparation of Allyl-substituted 1-Naphthol- and 1,4-Naphthoquinone DerivativesPentacarbonyl(methoxyphenylcarbene)chromium(0) (1) and the enynes 2-5 react on warming in di-n-butyl ether to give the tricarbonyl(2(or 3)-alkyl-3(or 2)-allyl-4-methoxy-1-naphthol)chromium(0) complexes 6-9. Chromatography of these compounds on silica gel under atmospheric conditions results in decomplexation and formation of a naphthol- (9 → 11) or a 1,4-naphtho-quinone derivative (8 → 10). Oxidation of 6-9 with silver(I) oxide leads exclusively to the quinones 12-14 and their tricarbonylchromium complexes 15-17. The products are characterized by spectroscopic methods.
    Notes: Pentacarbonyl(methoxyphenylcarben)chrom(0) (1) reagiert mit den 1,4-Eninen 2-5 beim Erwärmen in Di-n-butylether zu den Tricarbonyl(2(bzw. 3)-alkyl-3(bzw.2)-allyl-4-methoxy-1-naphthol)-chrom(0)-Komplexen 6-9. Diese werden bei Luftzutritt an Kieselgel zum Naphthol- (9 → 11) oder direkt zum 1,4-Naphthochinon-Derivat (8 → 10) dekomplexiert. Die Oxidation von 6-9 mit Silber(I)-oxid führt stets zu den Chinonen 12-14 und deren Tricarbonylchrom-Komplexen 15-17. Die Reaktionsprodukte werden spektroskopisch charakterisiert.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 84
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: „cis-Triaza-tris-σ-homobenzenes“ („cis-Benzene Triimine“). Syntheses and [σ2s + σ2s + σ2s]-Cycloreversions to 4,7-Dihydro-1H-1,4,7-triazoninescis-Triaza-tris-σ-homobenzene („cis-Benzene Triimine“) (2) has been synthesized from cis-trioxa-tris-σ-homobenzene („cis-benzene trioxide“) (1) via threefold epoxide-ring opening with sodium azide, tosylation (92% chiro-/scyllo-triazido tritosylates 9 (92-95%)/11 (5-8%)) and LAH-reduction (40-50%). The pKa1/pKa2-values of 6.43 and 1.90 show that no extraordinary basicity is connected with the specific orientation of the three aziridine rings. Metal ions, however, are readily complexed. Upon thermal activation, out of the threefold N-donor- and N-acceptor-substituted derivatives 18b-m, 18b-j undergo, mostly in a highly specific manner, a 3σ → 3 π-isomerisation reaction to the 4,7-dihydro-1 H-1,4,7-triazonine derivatives 24b-j. The activation barriers depend on the nature of the N-substituents and are higher for SO2R than for COR or alkyl groups. Mainly on the basis of the kinetic data and in analogy with earlier examples, a cooperative reaction mechanism via „trishomobenzenoid“ transition states (38) is held to be plausible for the 3σ → 3 π-transformations 18-24. With a ΔH≠-value of 111 ± 3 kJ · mol-1 (ΔS≠ = 4 ± 8J · K-1 · mol-1 (CD3CN)) for 18i, as a model for 2, it is obvious, that the aziridine ring participates much more readily, than the oxirane ring, in these [σ2s + σ2s + σ2s]-cycloreversion reactions and is comparable in this respect to the cyclopropane ring.
    Notes: cis-Triaza-tris-σ-homobenzol („cis-Benzoltriimin“) (2) wird ausgehend von cis-Trioxa-tris-σ-homobenzol („cis-Benzoltrioxid“) (1) über dreifache Epoxidöffnung mit Natriumazid, Tosylierung (92% chiro-/scyllo-Triazido-tritosylate 9 (92-95%)/11 (5-8%)) und LAH-Reduktion (40-50%) synthetisiert. Bei pKa1/pKa2-Werten von 6.43 und 1.90 ist mit der speziellen cis-Anordnung der drei Aziridinringe in 2 keine außergewöhnliche Basizität verknüpft. Andererseits werden Metall-Ionen leicht komplexiert. Von den dreifach N-akzeptor- bzw. N-donor-substituierten Derivaten 18b-m gehen beim Erhitzen 18b-j - in der Regel -  hochselektiv die 3σ → 3 π-Isomerisierung zu den 4,7-Dihydro-1H-1,4,7-triazonin-Derivaten 24b-j ein. Die Aktivierungsbarrieren sind von der N-Substitution abhängig und sind bei SO2R- durchweg höher als bei COR- oder Alkyl-Substitution. Vor allem auf Grund der kinetischen Daten wird für die 3σ → 3 π-Umwandlungen 18 → 24 in Analogie zu früheren Beispielen ein kooperativer Reaktionsablauf über „trishomobenzoide“ Übergangszustände (38) vorgezogen. Mit ΔH≠ = 111 ± 3kJ · mol-1 (ΔS≠ =4 ± 8 J · K-1 · mol-1 (CD3CN)) für 18i, als Modell für 2, bestätigt sich, daß der Aziridinring, dem Cyclopropanring vergleichbar, sehr viel leichter als der Oxiranring in diesen [σ2s + σ2s + σ2s]-Cycloreversionen partizipiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: „cis-Diaza-bis-σ-homobenzenes“ ([π2s + σ2s + σ2s]-Cycloreversion) -1,4-Dihydro-1,4-diazocines („Aromaticity“)Starting from „cis-benzene triimine“ (3) the N,N′-disubstituted derivatives 8b-f are synthesized in 90-40% yield. Nitrosation to the N-nitroso compounds 10b-f, spectroscopically identified below -30°C, and N2O-elimination lead to the cis-diaza-bis-σ-homobenzenes („cis-benzene diimines“) 11b-f. Their [π2s + σ2s + σ2s]-cycloreversion to the 1,4-disubstituted 1,4-dihydro-1,4-diazocins 14b-e is, depending on the nature of the N-substituent, so fast, that even under the mild reaction conditions (- 30 to - 10°C) only 11b,f and e can be isolated and identified, resp. (11f yields only  -  via 14f?  -  polymers). With Ea = 97 ± 2 kJ · mol-1 (log A = 11.7; ΔH≠ = 92 ± 2kJ · mol-1; ΔS≠ = -31 ± 6 J · K-1 · mol-1) the most stable cis-benzene diimine 11b is clearly more labile than cis-benzene dioxide. From 14d the diazocine dianion 16 is obtainable by conventional means. The 1,4-dihydro-1,4-diazocine parent molecule 5 obtained by protonation of 16 is stable towards acid and base. From this and from systematic 1H- and 13C NMR studies it is concluded, that 5 and its donor-substituted derivatives 14e,g as well as its dianion 16 have a planar structure with strong 10-electron delocalisation („aromatic“ diaza[8]annulenes) whilst the acceptor-substituted derivatives 14b-d prefer the twist-boat-chair conformation and are therefore not diatropic.
    Notes: Ausgehend von „cis-Benzoltriimin“ (3) werden mit 90-40% Ausbeute die N,N′-disubstituierten Derivate 8b-f hergestellt. Nitrosierung zu den unterhalb -30° C 1H-NMR-spektroskopisch identifizierten N-Nitrosoverbindungen 10b-f und N2O-Eliminierung führen zu den cis-Diaza-bis-σ-homobenzolen („cis-Benzoldiiminen“) 11b-f. Deren [π2s + σ2s + σ2s]-Cycloreversion zu den 1,4-disubstituierten 1,4-Dihydro-1,4-diazocinen 14b-e(11f liefert - über 14f? - nur Polymere) ist je nach Art der N-Substitution derart schnell, daß unter den milden Herstellungsbedingungen ( - 30 bis -10°C) nur 11b,f und e isolierbar bzw. identifizierbar sind. Mit Ea = 97 ± 2kJ · mol-1 (log A = 11.7; ΔH≠ = 92 ± 2 kJ · mol-1; ΔS≠ = -31 ± 6J · K-1 · mol-1) ist das stabilste cis-Benzoldiimin 11b deutlich labiler als cis-Benzoldioxid. Aus 14d ist konventionell das 1,4-Diazocin-Dianion 16 erhältlich. Das durch Protonierung von 16 gewonnene 1,4-Dihydro-1,4-diazocin-Grundgerüst 5 ist bei Säure- bzw. Baseeinwirkung stabil. Daraus und aus systematischen 1H- und 13C-NMR-Untersuchungen wird gefolgert, daß es sich bei dem Grundgerüst 5, den donorsubstituierten Derivaten 14e, g und dem Dianion 16 um planare, durch cyclische 10-Elektronendelokalisierung charakterisierte „aromatische“ Diaza[8]annulene handelt, während die akzeptorsubstituierten Derivate 14b-d die mobile Twist-Boot-Sessel-Konformation bevorzugen und nicht diatrop sind.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3249-3261 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycyclic Compounds, XVIII. Synthesis of Isomeric Tetralones by Group Transpositions in Partially Hydrogenated NaphthalenesFour pairs of carbon atoms change their positions relative to C-1/C-2 of 1 in the transposition sequence 1 → 4 → 5 → 3 starting with the oxanorbornadienes 1. This can be used for 1,2- and 1,4-transpositions as shown in a variety of examples. During the conversion of 1b to 3f three groups move into other positions.
    Notes: Bei der Transpositionsfolge 1 → 4 → 5 → 3 der Oxanorbornadiene 1 vertauschen vier Paare von Kohlenstoffatomen ihre Positionen relativ zu C-1/C-2 von 1. Wie an einer Reihe von Beispielen gezeigt wird, läßt sich dies präparativ zu 1,2- und 1,4-Transpositionen verwenden. Bei der Abwandlung 1b → 3f rücken drei Gruppen in andere Positionen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3275-3293 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rearrangement Reactions in Intramolecular Electrophilic Cyclizations in the Triphenylmethane SeriesAcid or acetyl bromide catalyzed cyclizations of 1,3-dihydro-1-(4-methoxyphenyl)-3,3-dimethyl-1-[2-(1-methylethenyl)phenyl]isobenzofuran (2a) and its 3-methoxyphenyl analog 2c lead via „ipso“ attack to the rearranged spiro derivatives 3b and 3b′. Only the corresponding 3-methoxyphenyl derivative 2b cyclizes in a skeletal conforming way to a mixture of the spiro compounds 3b and 3b′. Cleavage of these with lithium in tetrahydrofuran yields the carbinols 4b and 4b′ which are cyclized with ZnCl2/HCl to the same 9,13b-dihydro-6-methoxy-5,5,9,9-tetramethyl-5H-naphth[3,2,1-de]anthracene (5b). Treatment of 5b with AlCl3 in benzene leads through ring-cleavage and reclosure reactions to the 2-methoxy isomer 5b′. The dynamic stereochemistry of 5b and 5b′ and their derivatives corresponds to that of the parent compounds of this series, already investigated earlier, and is here characterized by the occurence of two rapidly equilibrating diastereomeric racemates.
    Notes: Die mit Säuren oder Acetylbromid katalysierten Cyclisierungen von 1,3-Dihydro-1-(4-methoxy-phenyl)-3,3-dimethyl-1-[2-(1-methylethenyl)phenyl]isobenzofuran (2a) und seinem 2-Methoxy-phenyl-Analogon 2c führen über „Ipso“-Attacken zu den umgelagerten Spiroderivaten 3b bzw. 3b′. Nur das entsprechende 3-Methoxyphenyl-Derivat 2b cyclisiert gerüstkonform zu einem Gemisch der Spiroverbindungen 3b und 3b′. Deren Spaltung mit Lithium in Tetrahydrofuran liefert die Carbinole 4b und 4b′, die mit ZnCl2/HCl zum gleichen 9,13b-Dihydro-6-methoxy-5,5,9,9-tetramethyl-5H-naphth[3,2,1-de]anthracen (5b) cyclisiert werden. Behandlung von 5b mit AlCl3in Benzol führt über Ringspaltungs- und erneute Ringschlußreaktionen zum 2-Methoxy-Isomeren 5b′. Die dynamische Stereochemie von 5b und 5b′ und deren Derivaten entspricht der der bereits früher untersuchten Grundkörper dieser Reihe, ist hier aber durch das Vorliegen zweier rasch äquilibrierender diastereomerer Racemate charakterisiert.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3313-3317 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: λ5-Phosphorine Derivatives with Functional Groups at the Phosphorine Ring: 1,1,4-Trimethoxy-2,6-diphenyl-λ5-phosphorine4-Acetylamino-1,1-dimethoxy-2,6-diphenyl-λ5-phosphorine (1) was hydrolyzed under various conditions to the one- or twofold unsaturated ketones 7 and 3, resp. These ketones were deprotonated or reduced and methylated to 1,1,4-trimethoxy-2,6-diphenyl-λ5-phosphorine (8) which was characterized as stable crystalline tricarbonylchromium complex 9. In a similar manner 1,4-dimethoxy-1,2,6-triphenyl-λ5-phosphorine (10) was obtained and transformed into the tricarbonylchromium complex 11.
    Notes: Ausgehend von 4-Acetylamino-1,1-dimethoxy-2,6-diphenyl-λ5-phosphorin (1) konnten wir über die bei der Hydrolyse entstehenden einfach bzw. doppelt ungesättigten Ketone 7 bzw. 3 nach Deprotonieren bzw. Reduktion und Alkylieren 1,1,4-Trimethoxy-2,6-diphenyl-λ5-phosphorin (8) darstellen und als beständigen, kristallisierten Tricarbonylchrom-Komplex 9 charakterisieren. In ähnlicher Weise wurde auch 1,4-Dimethoxy-1,2,6-triphenyl-λ5-phosphorin (10) erhalten und in den Tricarbonylchrom-Komplex 11 übergeführt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3357-3365 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of New Germylene Complexes of Chromium and TungstenPentacarbonyl[dichloro(tetrahydrofuran)germylene]chromium(0) (1) and -tungsten(0) (2) react with (diphenylamino)trimethylstannane to give the NR2-substituted germylene complexes 3 and 4, respectively. Complexes with Ge(OR)2 ligands are shown to be very unstable. Reaction of [bis(mesitylthio)germylene]pentacarbonylchromium(0) (5) with boron trichloride, bromide, and iodide leads to the dihalogenogermylene complexes 7, 8, and 9. Properties and some reactions of the prepared compounds are described. The π-acceptor capability of the germylenes is discussed on the basis of vCO-data.
    Notes: Durch Umsetzung von Pentacarbonyl[dichlor(tetrahydrofuran)germylen]chrom(0) (1) und -wolfram(0) (2) mit (Diphenylamino)trimethylstannan werden die NR2-substituierten Germylen-Komplexe 3 und 4 hergestellt. Komplexe mit Ge(OR)2-Liganden erweisen sich als sehr instabil. Bei der Reaktion von [Bis(mesitylthio)germylen]pentacarbonylchrom(0) (5) mit Bortrichlorid, -bromid und -iodid entstehen die Dihalogengermylen-Komplexe 7, 8 und 9. Eigenschaften und einige Reaktionen der dargestellten Verbindungen werden beschrieben. Die π-Akzeptorfähigkeit der Germylene wird anhand der vCO-Daten diskutiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3377-3380 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal Ketene Compounds, VII. Transition Metal Substituted Ketenes with Chelate LigandsThe title compounds can be obtained by the reaction of either (5) with the chelate ligands (CH3)2P-[CH2]nP(CH3)2 (n = 1-2) or (PF2)2NCH3.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3389-3393 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 7-Deazainosine by Phase Transfer GlycosidationPhase transfer glycosidation of 4-methoxy-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine (2) with 2,3,5-tri-O-benzyl-1-bromo-D-ribose (3) leads to selective N-7 ribosidation giving a mixture of the anomers 4/5. They are separated chromatographically and the anomeric configuration is assigned by 1H and 13C NMR spectroscopy. The protecting groups of 5 were removed by hydrolysis (methyl ether), desulfurisation (methylthio residue) and catalytic hydrogenation (benzyl ether) yielding 7-(ß-D-ribofuranosyl)pyrrolo[2,3-d]pyrimidine-4(3H)-one (1), the 7-deaza derivative of inosine.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3394-3395 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Phosporus, 98. Simple Preparation of Trilithiumheptaphosphide from White Phosphorus and LithiumdihydrogenphosphideTrilithiumheptaphosphide (1) is easily obtained with 95% yield by the reaction of white phosphorus with an excess of lithiumdihydrogenphosphide.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3303-3312 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbenes, 22. Phosphenes: Trapping Reactions of (Diphenylmethylene)phenylphosphane Oxide by [2 + 2]-Cycloaddition with AldehydesThe photolysis of (diazobenzyl)diphenylphosphane oxide (5) in benzene yields the short-lived (diphenylmethylene)phenylphosphane oxide (15) via the carbene 12. The heterocumulene is trapped by aromatic aldehydes, which are added to the reaction mixture, in a [2 + 2]-cycloaddition reaction with formation of the 1,2λ5-oxaphosphetanes 16a - e. Carbene reactions with the solvent (formation of the norcaradiene 13) as well as with the trapping reagents (formation of the C/H-insertion products 10a and b) cannot be avoided. With the α,β-unsaturated aldehydes 22a - c, the 1,2λ5-oxaphosphetanes 23a - c are primarily formed. They undergo a complete or a partial photofragmentation to the 1,3-butadienes 24a - c and phenylphosphane dioxide (25).
    Notes: Die Photolyse von (Diazobenzyl)diphenylphosphan-oxid (5) in Benzol liefert das kurzlebige (Diphenylmethylen)phenylphosphan-oxid (15) über das Carben 12. Das Heterocumulen wird durch der Photolyselösung zugesetzte aromatische Aldehyde in einer [2 + 2]-Cycloaddition abgefangen unter Bildung der 1,2λ5-Oxaphosphetane 16a-e. Carbenreaktionen mit dem Solvens (Bildung des Norcaradiens 13) sowie den Abfangreagenzien (Bildung der C/H-Insertionsprodukte 10a und b) lassen sich nicht vermeiden. Mit den α,β-ungesättigten Aldehyden 22a-c werden primär die 1,2λ5-Oxaphosphetane 23a-c gebildet; sie gehen ganz oder teilweise Photofragmentierung zu den 1,3-Butadienen 24a-c und Phenylphosphan-dioxid (25) ein.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 94
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Substituted Phosphanes, Arsanes, and Stibanes, XXIII. Stable Transition Metal Dimethylarsanes Bearing a Tricarbonyl(cyclopentadienyl)chromium, -molybdenum or -tungsten SubstituentBy the interaction of (CH3)2AsCl with [C5H5(CO)3M]Na or C5H5(CO)3M - Si(CH3)3 stable carbonyl(cyclopentadienyl)metal dimethylarsanes of the formula C5H5(CO)3M - As(CH3)2 (M = Cr, Mo, W) (1 - 3) are obtained for the first time. Their thermal treatment in the solid state yields [(CH3)2As]2 and [C5H5(CO)3M]2, in solution with loss of CO the cyclic species [C5H5(CO)2M - As(CH3)2]2 4a (Mo), 4b (W) are formed. Under photolytic conditions in addition to 4a, b the aggregation products trans-C5H5(CO)2[C5H5(CO)3M - As(CH3)2]M - As (CH3)2 (5a, b) and [trans-C5H5(CO)2M - As(CH3)2]x (6a, b) are isolated. Alkyl halides and (CH3)3SiI readily convert 1 - 3 into the cationic complexes [C5H5(CO)3M - As(CH3)2R]X (R = CH3, CH2C(O)C6H5, CH2Si(CH3)3, Si(CH3)3; X = Br, I) (7a - f). With chlorine or bromine the extremely labile dihalogen adducts C5H5(CO)3M - As(CH3)2Hal2 (8a - c) are formed, which rapidly decompose to (CH3)2AsHal and C5H5(CO)3MoHal or C5H5(CO)3WH. HCl, CF3CO2H, (CH3)3SnH, Na/Hg, CH3MgI, and (CH3)3PCH2 cleave the transition metal-arsenic bond under very mild conditions.
    Notes: Durch die Reaktion von (CH3)2AsCl mit [C5H5(CO)3M]Na oder C5H5(CO)3M - Si(CH3)3 werden erstmals stabile Carbonyl(cyclopentadienyl)metall-dimethylarsane der Form C5H5(CO)3M - As(CH3)2 (M = Cr, Mo, W) (1 - 3) erhalten. Ihre thermische Behandlung in Substanz liefert [(CH3)2As]2 und [C5H5(CO)3M]2, in Lösung unter CO-Eliminierung die cyclischen Verbindungen [C5H5(CO)2M - As(CH3)2]2 4a (Mo), 4b (W). Unter photolytischen Bedingungen werden zusätzlich zu 4a, b die Aggregationsprodukte trans-C5H5(CO)2[C5H5(CO)3M - As(CH3)2]M - As(CH3)2 (5a, b) und [trans-C5H5(CO)2M  -  As(CH3)2]x (6a, b) isoliert. Alkylhalogenide und (CH3)3SiI überführen 1 - 3 glatt in die kationischen Komplexe [C5H5(CO)3M - As(CH3)2R]X (R = CH3, CH2C(O)C6H5, CH2Si(CH3)3, Si(CH3)3; X = Br, I) (7a - f). Mit Chlor oder Brom werden die extrem labilen Dihalogenaddukte C5H5(CO)3M - As(CH3)2Hal2 (8a - c) gebildet, die rasch zu (CH3)2AsHal und C5H5(CO)3MoHal bzw. C5H5(CO)3WH zerfallen. HCl, CF3CO2H, (CH3)3SnH, Na/Hg, CH3MgI und (CH3)3PCH2 spalten die Übergangsmetall-Arsenbindung unter sehr milden Bedingungen.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3342-3351 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Poly(organylthio)butenynes and -butatrienes with Electrophilic ReagentsStarting from the poly(organylthio)substituted butenynes 1 and the butatrienes 2 or 5 the butadiene derivatives 3,4,6,7 and 8 are obtained by addition of halogens, hydrogen halides or 4-chlorophenylsulfenyl chloride. The chlorine addition products 3, not directly available from 2, are prepared by the reactions of 7 with sulfuryl chloride. The tert-butylthio substituted butatriene 2d reacts with iodine, bromine and hydrobromic acid to the thiophene derivatives 10a, b and c, respectively, under elimination of one mole of isobutene. In the analogous reaction of 5 with bromine 11 is formed. The mechanism of this cyclization is discussed.
    Notes: Durch Addition von Halogenen, Halogenwasserstoffsäuren und 4-Chlorphenylsulfenylchlorid an die poly(organylthio)-substituierten Butenine 1 und Butatriene 2 oder 5 sind die Butadienderivate 3,4,6,7 und 8 erhältlich. Die nicht direkt aus 2 zugänglichen Chloradditionsprodukte 3 werden durch Reaktion von 7 mit Sulfurylchlorid hergestellt. Das tert-butylthio-substituierte Butatrien 2d setzt sich mit Iod, Brom und Bromwasserstoffsäure unter Abspaltung von einem mol Isobuten zu den Thiophenderivaten 10a, b bzw. c um. In der analogen Reaktion von 5 mit Brom entsteht 11. Der Mechanismus dieses Ringschlusses wird diskutiert.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3366-3368 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of μ-(Dihalogenogermylene)-bis(pentacarbonyltungsten) ComplexesThe reaction of [bis(mesitylthio)germylene]pentacarbonyltungsten(0) (1) with boron trichloride and tribromide leads to the μ-(dihalogenogermylene)-bis(pentacarbonyltungsten) complexes 2 and 3. A reaction mechanism is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3373-3376 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Chemistry of Amino Oximes, XII. Synthesis and Properties of 4,5,6,7-Tetrahydro-1,2,6-oxadiazepines4,5,6,7-Tetrahydro-1,2,6-oxadiazepines (2a - d) were prepared by the reaction of the syn-(E)-(benzylamino)propiophenone oximes 1a - d with formaldehyde. The ω-aminopropiophenone oximes 1e - g react with acetone or benzaldehyde to give azomethines 6e - g and 7e - g, respectively.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3384-3388 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and X-Ray Structure of (E)-α-(Trifluoromethyl)stilbeneStarting from benzyltriphenylphosphonium chloride and ω,ω,ω-trifluoroacetophenone α-(trifluoromethyl)stilbene was prepared with 91% yield with a phase transfer-catalyzed Wittig reaction with solid KF but without bases. The isolated isomer was found by X-ray structure analysis to have the thermodynamic preferred (E)-configuration. For this configuration it was determined a torsion angle of 71.3° between the two cis-configurated phenyl rings because of steric hindrance. AH⃜F hydrogen bridge (distance: 223.8 pm) stabilizes the (E)-isomer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3396-3400 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 1,2,5,6-Tetrahydropyrimidines On a Base Induced Ring Enlargement of 1H-3-Pyrazolines5,5-Bis(trifluoromethyl)-2-[2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-1H-3-pyrazolines 1 on treatment with bases are transformed into 1,2,5,6-tetrahydro-2,2,6,6-tetrakis(trifluoromethyl)pyrimidines 2. A reaction mechanism is proposed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3405-3415 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Rearrangement of Cyclic Semi-aminals with α-Mercapto GroupsReaction of thioacetic acid, thiobenzoic acid as well as 2-aminothiophenol with racemic cyclic semi-aminal 3 takes a diastereoselective course to racemic 4a, b, c. The ambident thiazolidine-2-thione reacts analogously, however by attack of nitrogen yielding 4d. The possibilities for rearrangement of adducts 4 are discussed and the structure of the rearranged products is examinated by x-ray analysis of 9c as well as by 13C NMR spectroscopy. The course of the diastereoselective rearrangement to the racemic mixture (α/β) of 2-azaspiro[4.4]nonenes 9a - d is discussed by aid of the results.
    Notes: Die Reaktion von Thioessigsäure, Thiobenzoesäure und 2-Aminothiophenol mit dem racemischen cyclischen Halbaminal 3 erfolgt diastereoselektiv unter Erhaltung der Halbaminal-Struktur zu den Racematen (α/β) 4a, b, c. Das ambidente Thiazolidin-2-thion setzt sich analog, jedoch unter Anlagerung des Stickstoff-Atoms, zu 4d um. Die Umlagerungsmöglichkeiten der Addukte 4 werden diskutiert, und die Struktur der Umlagerungsprodukte wird durch eine Röntgenstrukturanalyse am Beispiel des Aminophenylthio-Derivates 9c sowie 13C-NMR-spektroskopisch untersucht. Der Verlauf der diastereoselektiven Umlagerung zu den racemischen (α/β) 2-Azaspiro[4.4]-nonen-Derivaten 9a - d wird an Hand der Ergebnisse diskutiert.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...