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  • 1
    Electronic Resource
    Electronic Resource
    Structures and Electrical Properties of Some New Organic Conductors Derived from the Donor Molecule TMET (S,S,S,S,-Bis(dimethylethylenedithio) tetrathiafulvalene) (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 942-953 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystal structures and electrical properties of radical-cation salts of the chiral organic donor TMET (S,S,S,S,-bis-(dimethylethylenedithio)tetrathiafulvalene) are described. Two structural types, 2:1 with octahedral anions Pf-6, AsF-6, SbF-6, I-3 (incommensurate), and 3:2 with tetrahedral anions BF-4, CIO-4, ReO-4 are observed. Resistivity measurements between 2 and 298 K indicate that the 3:2 types are organic metals, while the other compounds are semiconductors. (TMET)3(CIO4)2 is metallic down to about 120 K at ambient pressure and remains metallic down to 2 K at 8 kbar.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700405
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  • 2
    Electronic Resource
    Electronic Resource
    Metabolism of carotenoids in salmonidsParts of this series were presented at the 8th Int. Symp. on Carotenoids, Boston, USA, 1987, by K. Schiedt.. Part 2Part 1 [1].. Distribution and absolute configuration of idoxanthin in various organs and tissues of one atlantic salmon (Salmo salar, L.) fed with astaxanthin (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 881-886 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The content of total carotenoids and the ratio astaxanthin/idoxanthin ( = 3,3′-dihydroxy-β,β-carotene-4,4′-dione/3,3′,4′-trihydroxy-β,β-caroten-4-one) in varoius organs and tissues of one Atlantic salmon (Salmo salar, L.) reared indoors in a tank were analyzed after feeding ‘racemic’ ((3R,3′R)/(3R,3′S; meso)/(3S,3′S) 1:2:) astaxanthin (90 mg/kg feed) during one yera. Configurational analysis of astaxanthin was carried out via the (-)-dicamphanate derivative and that of idoxanthin after reaction with (+)-(S)-l-(l-naphthyl)ethyl isocyanate. Separation of all eight optical isomers of idoxanthin-tricarbamate derivatives by HPLC is described. In salmon, enzymatic reduction of astaxanthin was found to be sterospecific leading to th (4′R)-hydroxy group irrespective of the configuration at C(3′), thus resulting in four different stereoisomers of idoxanthin formed from (3R,3′R), (3R,3′S; meso)-, and (3S3′S)-astaxanthin present in the diet.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710425
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  • 3
    Electronic Resource
    Electronic Resource
    Modelling the Metabolic Epimerization of Anti-inflammatory 2-Arylpropanoyl-coenzyme-A Conjugates: Solvent effects on the 1H/2H exchange in S-[2-(dimethylamino)ethyl] 2-phenylpropanethioate (1989)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 72 (1989), S. 1225-1232 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H/2H exchange at the methine position of S-[2-(dimethylamino)ethyl] 2-phenylpropanethioate (DEPP) in solvent/D2O mixtures was taken as a model reaction for the metabolic epimerization of 2-arylpropanoyl-coenzyme-A thioesters and was monitored by 1H-NMR spectroscopy at 37°. The solvents used were (D6)acetone, (D3)acetonitrile, (D6)dimethylsulfoxide, and (D5)pyridine. In the investigated range of D2O percentage (10-50%), the exchange reaction was found to increase linearily with D2O content and with the basicity of the organic solvent, the fastest rates being close to 0.09 h-1 (t½ ca. 8 h). These rates are slower than those observed in vivo for the configurational inversion of profens, and they are elicited in totally unphysiological concentrations of bases. The hypothesis thus formulated is that the metabolic epimerization of 2-arylpropanoyl-coenzyme-A thioesters cannot occur nonenzymatically.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19890720606
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  • 4
    Electronic Resource
    Electronic Resource
    Synthese und spektrale Charakterisierung von blauen Benzenazofarbstoffen (1986)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 497-514 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Spectral Characterization of Blue Azo Dyes of the Benzene Series53 Donor-acceptor substituted azo dyes of the benzene series were prepared by diazonium-coupling reactions (1 a-s) or halogen-cyanide exchange (→2 a-x, 3 a-j). Described are the preparation of the amines 4 a-m and the coupling compounds 5 a-t and the procedure of diazotizing and coupling.The colouristic and spectroscopic data show that compounds of the general formula 1 are excellent brilliant blue azo dyes useful for dyeing polyester material.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19863280406
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  • 5
    Electronic Resource
    Electronic Resource
    Thiohydrazide und 1,3,4-Thiadiazole durch Hydrazinolyse von Dithioestern (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 649-658 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thiohydrazides and 1,3,4-Thiadiazoles by Hydrazinolysis of Dithiocarboxylic EstersThe reaction of 1,1-dithiooxalicesters 1 and heteroaryldithiocarboxylicesters 2 with excess hydrazine yields stable thiohydrazides 3 and 4, respectively. If the hydrazinolysis is carried out with only 0,5 equivalent hydrazine 1,3,4-thiadiazoles 6 and 7, equally substituted in position 2 and 5, result. 1,3,4-Thiadiazoes are also formed by heating the isolated thiohydrazides 3 and 4. The thiohydrazides 3 and 4 are also excellent starting compounds for the synthesis of unsymmetrically substituted 1,3,4-thiadiazoles (8, 9), especially for derivatives with carbamoyl or heteroaryl residues.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310415
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  • 6
    Electronic Resource
    Electronic Resource
    Versuche zur Synthese sterisch gehinderter Thiazylarene und deren Beziehung zu Arylsulfenylnitrenen (1987)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 81-86 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts to Synthesize Sterically Hindered Thiazyl Arenes and Their Relationship to Arylsulfenyl NitrenesUp till now all attempts to synthesize organic thiazyl compounds in substance failed. Stabilization leads to the corresponding disulfide 2, the thioaminyl radical 7 and the sulphur diimide 8. Formally thiazyl compounds 1 and sulfenyl nitrenes 1 were resonance structures. Via sulfenyl nitrenes 1 the formation of 2, 7, 8 can be discussed. An in situ preparation of sulfenyl nitrene 1a via the sulfenyl chloride 5a, synthesized by chlorination of the disulfide 2a, and the sulfenyl azide 6a is described in detail. 1a can also be prepared from the sulfenyl amide 4a by oxidation. The structures of the radicals 7a-f and 12f are discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19873290111
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  • 7
    Electronic Resource
    Electronic Resource
    Dithiocarbonsäuren, Dithiocarbonsäureester oder Thiocarbonsäureamide aus methylenaktiven Chlormethylverbindungen und Schwefel (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 243-262 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dithiocarboxylic Acids, Dithiocarboxylic Esters, or Thiocarboxylic Amides by Reaction of Methylene-active Chloromethyl Compounds with SulfurWith a mixture of sulfur and amine in DMF at room temperature halomethyl compounds (1, 5-10) can be oxidized to give thiocarboxylic acids (2, 11-16) and their derivatives (3, 4, 17-35). We studied this reaction in detail especially with chloroacetic derivatives (11-15) or chloromethyl heterocycles (16) formally derived from chloroacetic acid.The resulting thiooxalic acid derivatives (11-27) represent activated acids and very useful C2-synthons, especially for the synthesis of heterocycles.Oxidation in the presence of triethyl amine leads to dithiocarboxylates (11-16) which can be alkylated to dithioesters (17-27) in high yields.As a rule, with different primary and secondary amines instead of tertiary amines these dithiocarboxylates or dithiocarboxylic esters can be transformed already at low temperatures to thioamides (28-35).
    Additional Material: 14 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310211
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  • 8
    Electronic Resource
    Electronic Resource
    Einführung einer Dreifachbindung in das Bicyclo[6.1.0]nonan-Gerüst (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 1087-1094 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Introduction of a Triple Bond into the Bicyclo[6.1.0]nonane SkeletonThe introduction of a triple bond into the bicyclo[6.1.0]nonane skeleton is investigated by applying the selenadiazole method to the ketones 1a-c, accessible on different pathways. The highly strained bicyclo[6.1.0]nonynes 2a and 2b can be isolated in pure state. The regioselectivity of the ring-closure reaction yielding the selenadiazoles determines the position of the tripe bond.
    Notes: Ausgehend von den auf verschiedenen Wegen zugänglichen Ketonen 1a-c wird die Einführung einer Dreifachbindung in das Bicyclo[6.1.0]nonan-Gerüst mit Hilfe der Selenadiazol-Methode untersucht. Dabei Können die hochgespannten Bicyclo-[6.1.0]nonine 2a und 2b in reiner Form isoliert werden. Maßgeblich für die Position der Dreifachbindung ist die Regioselektivität der Ringschlußreaktion bei der Selenadiazolbildung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870877
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  • 9
    Electronic Resource
    Electronic Resource
    Verbesserte Synthese von 2,6-Dicyan-1,5-dimethylsemibullvalen aus 1,5-Dimethylbicyclo[3.3.0]octan-3,7-dion (1988)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 1155-1163 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Improved Synthesis of 2,6-Dicyano-1,5-dimethylsemibullvalene from 1,5-Dimethylbicyclo[3.3.0]octane-3,7-dioneThe 3,7-diketone 6 reacts with thiophenols in the presense of titanium tetrachloride/triethylamine affording equal amounts of the vinyl sulfides C2/Cs-13 in 87-93% yield. Equilibration of the 1:1 mixture of C2/Cs-13 is catalyzed by trifluoroacetic acid and produces a 3:1 ratio of C2- and Cs-13. Sodium perborate tetrahydrate in acetic acid oxidizes the vinyl sulfides C2/Cs-13 to the vinyl sulfones C2/Cs-14 in almost quantitative yield. Potassium cyanide supported on aluminium oxide in boiling 2-methyl-2-butanol converts the latter into a mixture of the α,β-unsaturated dinitriles 8, 17, Cs-18, 19, 20 which are separated through chromatography. The major product 8 (yield 45-55%) exchanges the allylic protons on treatment with sodium methoxide in methan-[D]ol yielding [D4]-8. Both dinitriles 8 and [D4]-8 are brominated by N-bromosuccinimide in dichloromethane to afford the exo,exo-4,8-dibromodinitriles 22 and [D2]-22, respectively, which are debrominated by means of the zinc/copper reagent. Thus, a 78-85% yield of the 2,6-dicyanosemibullvalenes 1 and [D2]-1, respectively, is achieved on a 2-g scale.
    Notes: Das 3,7-Diketon 6 reagiert mit Thiophenolen in Gegenwart von Titan(IV)-chlorid/Triethylamin zu gleichen Mengen der Bis(vinylsulfide)C2/Cs-13 (Ausb. 87-93%), die unter Trifluoressigsäure-Katalyse zu einem (3:1)-Gemisch äquilibriert werden. Oxidation von C2/Cs-13 mit Natriumperborat-tetrahydrat in Essigsäure ergibt fast quantitativ die Bis(vinylsulfone) C2/Cs-14. Diese liefern mit Kaliumcyanid auf Aluminiumoxid in siedendem 2-Methyl-2-butanol ein Gemisch der α,β-ungesättigten Dinitrile 8, 17, Cs-18, 19, 20, die chromatographisch getrennt werden. Das Hauptprodukt 8 (Ausb. 45-55%) wird durch Behandeln mit Natriummethanolat in Methan-[D]ol an den Allylpositionen deuteriert. Beide Dinitrile 8 und [D4]-8 werden mit N-Bromsuccinimid in Dichlormethan zu den exo,exo-Dibromdinitrilen 22 bzw. [D2]-22 bromiert. Diese werden mit Zink/Kupfer debromiert, wobei im 2-g-Maßstab mit 78-85proz. Ausbeute die 2,6-Dicyansemibullvalene 1 bzw. [D2]-1 erhalten werden.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198819881209
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  • 10
    Electronic Resource
    Electronic Resource
    2,6-Dicyanbarbaralane durch Phasentransfer-katalysierte Halogenierung/Dehydrohalogenierung von Bicyclo[3.3.1]nona-2,6-dien-2,6-dicarbonitril (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 515-518 
    Details
    ISSN: 0170-2041
    Keywords: Barbaralanes ; Phase transfer catalysis ; Halogenation by hexahaloethanes ; Ring formation by dehydrohalogenation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2,6-Dicyanobarbaralanes Through Phase Transfer Catalyzed Halogenation/Dehydrohalogenation of Bicyclo[3.3.1]nona-2,6-diene-2,6-dicarbonitrile1)Treatment of bicyclo[3.3.1]nona-2,6-diene-2,6-dicarbonitrile (1) with sodium methoxide in methan-[D]ol or with alkalideuteroxide in deuterium oxide unter the conditions of phase transfer catalysis leads to an exchange of the γ-protons for deuterium atoms producing [D4]-1. This is converted into the barbaralane-dicarbonitrile [D2]-3 by known methods. The carbanion generated from 1 by alkali hydroxide under the conditions of phase transfer catalysis is chlorinated by hexachloroethane. Ring-forming dehydrochlorination of the intermediate chlorinated dinitriles (presumably 2b and 4b) under the same reaction conditions yields predominantly 3 (76%) accompanied by small amounts of the 4-chlorobarbaralanedicarbonitrile 5b (11%), which are separated by chromatography.
    Notes: Durch Natriummethanolat in Methan-[D]ol oder durch Alkalideuteroxid in Deuteriumoxid unter Phasentransfer-Katalyse werden die γ-Protonen des Bicyclo[3.3.1]nona-2,6-dien-2,6-dicarbonitrils (1) gegen Deuterium ausgetauscht. Aus dem so erhaltenen [D4]-1 wird auf bekanntem Weg das Barbaralandicarbonitril [D2]-3 hergestellt. Das mit Alkalihydroxid unter Phasentransfer-Katalyse aus 1 erzeugte Carbanion wird durch Hexachlorethan chloriert. Cyclisierende Dehydrohalogenierung der intermediären chlorierten Dinitrile (vermutlich 2b und 4b) unter den gleichen Reaktionsbedingungen ergibt hauptsächlich 3 (76%) neben 4-Chlorbarbaralandicarbonitril 5b (11%), die chromatographisch getrennt werden.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890191
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