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  • 1
    Electronic Resource
    Electronic Resource
    Thermodynamics and kinetics of the interaction of copper (II) ions with native DNA (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 625-661 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on equilibrium binding studies, as well as on kinetic investigations, two types of interactions of Cu2+ ions with native DNA at low ionic strength could be characterized, namely, a nondenaturing and a denaturing complex formation. During a fast nondenaturing complex formation at low relative ligand concentrations and at low temperatures, different binding sites at the DNA bases become occupied by the metal ions. This type of interaction includes chelate formation of Cu2+ ions with atoms N(7) of purine bases and the oxygens of the corresponding phosphate groups, chelation between atoms N(7) and O of C(6) of the guanine bases, as well as the formation of specific intestrand crosslink complexes at adjacent G°C pairs of the sequence dGpC. CD spectra of the resulting nondenatured complex (DNA-Cu2+)nat may be interpreted in terms of a conformational change of DNA from the B-form to a C-like form on ligand binding. A slow cooperative denaturing complex formation occurs at increased copper concentrations and/or at increased temperatures. The uv absorption and CD spectra of the resulting complex, (DNA-Cu2+)denat, indicate DNA denaturation during this type of interaction. Such a conclusion is confirmed by microcalorimetric measurements, which show that the reaction consumes nearly the same amount of heat as acid denaturation of DNA.From these and the kinetic results, the following mechanism for the denaturing action of the ligands is suggested: binding of Cu2+ ions to atoms N(3) of the cytosine bases takes place when the cytosines come to the outside of the double helix as a result of statistical fluctuations. After the completion of the binding process, the bases cannot return to their initial positions, and thus local denaturation at the G·C pairs is brought about. The probability of the necessary fluctuations occurring is increased by chelation of Cu2+ ions between atoms N(7) and O of C(6) of the guanine bases during nondenaturing complex formation, which loosens one of the hydrogen bonds within the G·C pairs, as well as by raising the temperature. The implications of the new binding model, which comprises both the sequence-specific interstand crosslinks and the described mechanism of denaturing complex formation, are discussed and some predictions are made. The model is also used to explain the different renaturation properties of the denatured complexes of Cu2+, Cd2+, and Zn2+ ions with DNA.In temperature-jump experiments with the nondenatured complex (DNA-Cu2+)nat, a specific kinetic effect is observed, namely, the appearance of a lag in the response to the perturbation. The resulting sigmoidal shape of the kinetic curves is considered to be a consequence of the necessity of disrupting a certain number of the crosslinks existing in the nondenatured complex before the local unwinding of the binding regions (a main step of denaturing complex formation) may proceed.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180311
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  • 2
    Electronic Resource
    Electronic Resource
    Cyclopropylmethyl-, Äthylcyclopropyl- und Cyclopropylisopropylacetylen - Darstellung und Metallierungsreaktionen (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 2185-2196 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropylmethyl-, Cyclopropylethyl-, and Cyclopropylisopropylacetylene - Synthesis and Metalation ReactionsMethyl-(1b), ethyl-(1c) substituted cyclopropylacetylenes are prepared in 30-g-scale and metalated with n-buyllithium. With usual trapping reagents a number of new compounds (11 - 38) is produced and the following is shown: 1b is metalated only at the methyl group, 1c both at the methylene group and the cyclopropane ring, 1d exclusively at the cyclopropane ring. Dimetalations are not detectable even under drastic reaction conditions.
    Notes: Methyl-(1b), äthyl-(1c)substituiertes Cyclopropylacetylen werden in 30-g-Maßstab hergestellt und mit n-Butyllithium metalliert. Durch übliche Abfangreagenzien wird eine Vielzahl neuer Verbindungen (11 - 38) erhalten und folgendes gezeigt: 1b wird nur an der Methylgruppe metalliert, 1c sowohl an der Methylengruppe als auch am Cyclopropanring, 1d ausschließlich am Cyclopropanring; zweifache Metallierungen sind selbst unter drastischen Bedingungen nicht nachweisbar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090625
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  • 3
    Electronic Resource
    Electronic Resource
    Optisch aktive Übergangsmetall-Komplexe, L: Arylrotation in C5H5(CO)2Mo-Thioamidato-Komplexen (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 379-387 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Optically Active Transition Metal Complexes, L: Aryl Rotation in C5H5(CO)2Mo-Thioamidato ComplexesIn the thioamidato complexes C5H5(CO)2MoSC(R)NR′ with R′ = CH3, C6H5, CH(CH3)2, CH2C6H5,(S)-CH(CH3)(C6H5), in which R is an o-substituted aryl (2-CH3C6H4,2-CH3OC6H4, or 1-naphthyl), atropisomers A and B can be shown to exist by 1H NMR spectroscopy. The isomers differ in the mutual arrangement of the o-substituent and the C5H5 group. From the trend of the NMR spectroscopically determined barriers for the NSC  -  aryl rotation it follows that the large o-substituent passes by the sulfur atom and that the hindrance to rotation is due to the interaction of the o-hydrogen atom with the NR′group. This is supported by the behaviour of the 2,6-o-di-substituted mesityl complex 4 and by comparison of the thioamidato complexes with corresponding dithiocarboxylato and amidino complexes.
    Notes: In den Thioamidato-Komplexen C5H5(CO)2MoSC(R)NR′ mit R′ = CH3, C6H5, CH(CH3)2, CH2C6H5,(S)-CH(CH3)(C6H5), in denen R ein o-substituierter Aromat (2-CH3C6H4,2-CH3OC6H4 oder 1-Naphthyl) ist, lassen sich 1H-NMR-spektroskopisch Atropisomere A und B nachweisen, die sich in der gegenseitigen Stellung von o-Substituent und C5H5-Rest unterscheiden. Aus dem Gang der NMR-spektroskopisch bestimmten Barrieren für die NSC  -  Aryl-Rotation folgt, daß der große o-Substituent am Schwefelatom vorbeidreht und für die Rotationsbehinderung die Wechselwirkung des o-Wasserstoffatoms mit dem NR′-Rest ausschlaggebend ist. Dies wird durch das Verhalten des 2,6-o-disubstituierten Mesityl-Komplexes 4 und den Vergleich der Thioamidato-Komplexe mit entsprechenden Dithiocarboxylato- und Amidino-Komplexen bestätigt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110136
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  • 4
    Electronic Resource
    Electronic Resource
    Derivate des Borabenzols, X. Bildung von Borinato-Liganden aus einem 1-Bora-2,5-cyclohexadien-Derivat in Komplexen von Mangan, Rhenium und Eisen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1167-1170 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, X. Formation of Borinato Ligands from a 1-Bora-2,5-cyclohexadiene Derivative in Complexes of Manganese, Rhenium, and IronBorinato complexes LMn(CO)3, LRe(CO)3, and FeL2 (3-5), where L is the 4-methyl-1-phenylborinato ligand, are obtained by thermal reaction of 4,4-dimethyl-1-pheny-1-bora-2,5-cyclohexadiene (1) with Mn2 (CO)10 and Re2(CO)10 and by thermolysis of tricarbonyl(4,4-dimethyl-1-phenyl-1-bora-2,5-cyclohexadiene)iron (2).
    Notes: Borinato-Komplexe LMn(CO)3, LRe(CO)3 und FeL2 (3-5), wo L der 4-Methyl-1-phenylborinato-Ligand ist, werden durch thermische Reaktion von 4,4-Dimethyl-1-phenyl-1 bora-2,5-cyclohexadien (1) mit Mn2(CO)10 und Re2(CO)10 und durch Thermolyse von Tricarbonyl-(4,4-dimethyl-1-phenyl-1-bora-2,5-cyclohexadien)eisen (2) erhalten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100340
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  • 5
    Electronic Resource
    Electronic Resource
    Reaktionen des Perchlor-2-pyrons mit Grignard-Verbindungen und Lithiumorganylen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1000-1006 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Perchloro-2-pyrone with Grignard Reagents and Organolithium CompoundsPerchloro-2-pyrone (1) reacts with some Grignard reagents at -10 to -60°C to give the 6-alkyl-substituted pyrones 2a-c. Further reaction of 2a with methylmagnesium bromide leads to the allenediol 4a which is also formed from 1 and methyllithium. Likewise 4b-d are obtainable from 1 and other organolithium compounds. Contrary to methylmagnesium bromide all other investigated Grignard reagents transform 1 into the dihydropyrones 5a-d. - The different reaction courses by 1,2- or 1,4-addition of organometallic compounds to the intermediates 2 are discussed.
    Notes: Aus Perchlor-2-pyron (1) werden mit den entsprechenden Grignard-Reagenzien bei -10 bis -60°C die alkylsubstituierten Pyrone 2a-c erhalten. Die Weiterreaktion von 2a mit Methylmagnesiumbromid führt zu dem Allendiol 4 a, das auch aus 1 und Methyllithium entsteht. In gleicher Weise sind 4b-d aus 1 mit anderen Lithiumorganylen zugänglich. Im Gegensatz zum Methylmagnesiumbromid liefern alle anderen untersuchten Grignard-Verbindungen mit 1 die Dihydropyrone 5. - Der unterschiedliche Reaktionsverlauf einer 1,2- oder 1,4-Addition an die Zwischenstufen 2 wird diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100320
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis, Opiate Receptor Binding and Analgesic Activity of Enkephalin Analogues (1979)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 398-411 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and biological testing of analogues of Met-enkephalin, a recently discovered opioid peptide from mammalian brain, are described. Testing involved determination of affinity constants for an opiate receptor site and of analgesic potency in the tail-flick test in mouse. The effects on opioid activity of modifying various parts of the enkephalin molecule are discussed. Tyr-D-Ala-Gly-MePheMet (O)-olThe ending -ol added to the symbol of an amino acid designates the aminoalcohol obtained by reduction of the α-carboxyl group of the amino acid. (FK 33-824), which was highly active in these tests, was subsequently selected for clinical testing.The use of two complementary models - in vitro binding studies and in vivo test for analgesia - for the assessment of biological activity in the evaluation of analogues is explained.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19790620206
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  • 7
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Indols, VII. Synthesen in der Iboga-Reihe, III. Ibogamin, Ibogain und Epiibogamin (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1871-1895 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Indole, VII. Syntheses in the Iboga-Series, III. Ibogamine, Ibogaine, and EpiibogamineStarting from dimethyl malonate, methyl acrylate, o-nitrotoluene, diethyl oxalate, ethyl bromoacetate, and hydroxylamine, both the iboga and epiiboga alkaloids have been synthesised stereoselectively in only fourteen steps by a novel indole synthesis. This synthesis proves the configuration.
    Notes: Ausgehend von Malon- und Acrylester, o-Nitrotoluol, Oxalester, Bromessigester und Hydroxylamin werden in 14 Stufen jeweils stereoselektiv sowohl die Iboga- als auch die Epiiboga-Alkaloide nach einer neuen Indolsynthese erhalten. Diese Synthesen sind konfigurationsbeweisend.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751080611
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  • 8
    Electronic Resource
    Electronic Resource
    Cyclische Analoga von Divinylstannanen, Divinylboranen und pentahapto-Divinylboran-Komplexen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 760-772 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Analogues of Divinylstannanes, Divinylboranes, and pentahapto-Divinylborane ComplexesThe dialkynes X(C ≡ CH)2 with X=(CH3)2C, (CH3)2Si, and (CH2)2 afford the stannacyclodienes X(CH≡CH)2Sn(CH3)2 on hydrostannation with (CH3)2SnH2. These are transformed into the 1-phenylboracyclodienes X(CH=CH)2BC6H5 by treatment with C6H5BCl2. Complexation reactions yield the transition-metal complexes [X(CH=CH)2BC6H5]Fe(CO)3 and (C5H5)Co-[(CH3)2C(CH=CH)2BC6H5] wherein the ligands act as pentahapto-ligands. The structure of tricarbonyl(1,1-dimethyl-4-phenyl-1-sila-4-bora-2,5-cyclohexadiene)iron (6b) is determined by X-ray methods.
    Notes: Die Dialkine X(C ≡ CH)2 mit X — (CH3)2C, (CH3)2Si und (CH2)2 liefern bei der Hydrostannierung mit (CH3)2SnH2 die Stannacyclodiene X(CH=CH)2Sn(CH3)2. Diese werden durch Umsetzung mit C6H5BCl2 in die 1-Phenylboracyclodiene X(CH=CH)2BC6H5 übergeführt. Komplexierungsreaktionen ergeben die Übergangsmetall-Komplexe [X(CH=CH)2BC6H5]Fe(CO)3 und (C5H5)Co[(CH3)2C(CH=CH)2BC6H5], in denen die Boracyclodien-Liganden als pentahapto-Liganden fungieren. Die Struktur von Tricarbonyl(1, 1-dimethyl-4-phenyl-1-sila-4-bora-2,5-cyclo-hexadien)eisen (6b) wird röntgenographisch bestimmt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100240
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  • 9
    Electronic Resource
    Electronic Resource
    Darstellung und chemische Eigenschaften von 2,3-Dihydro-1,3,2λ5-benzoxazastibolen (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 2231-2242 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Chemical Properties of 2,3-Dihydro-1,3,2λ5-benzoxazastibolesThe synthesis of the benzoxazastiboles 1-9 starting from o-aminophenols and triarylantimony dibromides (route A) or o-aminoaroxyls and triarylstibines (route B) is described. These heterocycles do not react with bases, however with mineral acids solvolysis is observed. Temperatures above 25°C lead to further reactions, and finally a new nine-membered ring can be isolated. Under oxidative conditions a cleavage of the oxazastiboles takes place, and phenoxazinyl radicals are formed from the fragments. The regiospecifity of this reaction was confirmed by means of e.s.r. spectroscopy.
    Notes: Die Synthese der Benzoxazastibole 1-9 aus o-Aminophenolen und Triarylantimondibromiden (Weg A) oder o-Aminoaroxylen und Triarylstibinen (Weg B) wird beschrieben. Gegenüber basischen Reagentien sind die Heterocyclen stabil, während im sauren Medium Solvolyse erfolgt. Bei Temperaturen oberhalb 25°C findet Weiterreaktion zu neungliedrigen Ringsystemen statt. Unter oxidativen Bedingungen werden die Oxazastibole gespalten, wobei Phenoxazinyl-Radikale entstehen. Die Regiospezifität dieser Reaktion wird durch ESR-Untersuchungen nachgewiesen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090630
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  • 10
    Electronic Resource
    Electronic Resource
    Pilot scale exponential growth of Escherichia coli W to high cell concentration with temperature variation (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 839-846 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An efficient method to grow Escherichia coli W to high cell concentrations on the pilot scale is described and discussed. The method involves growth linked introduction of glucose; and ammonia to the culture, sparing with oxygen, and maintenance of aerobic conditions by gradually decreasing the temperature in the culture in order to keep the oxygen demand within the limits of the capacity of supply. Under these conditions the linear rate of cell mass production is actually the result of exponential growth with a gradually decreasing growth-rate constant.About 10 kg packed cells were produced in a 50 liter working-volume fermentor in one run of 13 hr. The concentration of the cells at the end of the growth was about 47 g dry cells/liter. The expenditure for nutrients was minimal and the controls were of simple automatic nature. From the determined yield constants for glucose, nitrogen, phosphorus, and oxygen it may be inferred that the cells grown by this method are similar to those grown exponentially at constant temperature.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260180606
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