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  • Organic Chemistry  (11)
  • Optical activity  (1)
  • Diels-Alder reactions
  • 1970-1974  (12)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 731 (1970), S. 67-79 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electrophilic Addition to Conjugated Dienes. Orientation and Stereochemistry of Additions of 4-Chlorobenzene-sulfenyl Chloride4-Chlorobenzenesulfenyl chloride (1) adds to butadiene, to some methyl, chloro and phenyl substituted butadienes and to dienoic esters (tables 1-3) to give under kinetic control (in unpolar solvents) predominantly 1,2-adducts (e. g. 2, 3), which rearrange in polar solvents into the thermodynamically more stable 1,4-adducts. Kinetically controlled 1,4-adducts are formed as minor products from methyl substituted dienes and as major products from some phenyl substituted dienes. The electrophilic sulfenyl group attacks position 4 of 1-substituted butadienes and position 1 of 2-substituted dienes (with the exception of chloroprene), in agreement with the orientation of diene syntheses with aromatic nitroso compounds.
    Notes: Bei der Addition von p-Chlorbenzolsulfenylchlorid (1) an Butadien, Methyl-, Phenyl- und Chlor-substituierte Butadiene sowie an Butadiencarbonsäureester (Tabellen 1-3) bilden sich bei kinetischer Steuerung der Reaktion (in unpolaren Lösungsmitteln) vorwiegend 1.2-Addukte (z. B. 2, 3), die durch Allyl-Umlagerung in polaren Lösungsmitteln in die thermodynamisch stabileren 1.4-Addukte übergehen. 1.4-Addukte entstehen jedoch auch bei kinetischer Steuerung, und zwar in geringen Mengen bei Methyl-substitutieren Dienen, als Hauptprodukte bei einigen aromatisch substituierten Dienen. Der elektrophile Sulfenyl-Rest wird bei 1-substituierten Dienen bevorzugt an C-4, bei 2-substituierten Dienen (mit Ausnahme von Chloropren) an C-1 addiert, was mit der Orientierung bei Diensynthesen mit Nitrosoaromaten übereinstimmt.
    Additional Material: 4 Tab.
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  • 2
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyhydroxyamino Compounds via Diene Synthesis of Nitroso Compounds, III1).Preparation and Stereochemistry of 1-p- Chloroanilino-2,3,4-trihydroxycyclohexene DerivativesThe preparation of 5 stereoisomeric N-acetyl-l-[p-chloroanilino]-2,3,4-triacetoxycyclo-hexanes (4a-e) is described; their configurations follow from the synthetic route and their properties.
    Notes: Die Darstellung von 5 stereoisomeren N-Acetyl-l -[p-chlor-anilino]-2.3.4-triacetoxy-cyclo-hexanen (4a-e) wird beschrieben. Ihre Konfigurationen folgen aus dem Syntheseweg und ihren Eigenschaften.
    Additional Material: 2 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 756 (1972), S. 112-127 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Stereochemistry of Allenes, I.  -  Preparation and Optical Resolution of a Series of Allenecarboxylic AcidsThe preparation and the optical resolution of some allenecarboxylic acids 1 are reported.
    Notes: Es werden die Darstellung und die optische Spaltung von Allencarbonsäuren 1 beschrieben.
    Additional Material: 1 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 762 (1972), S. 106-110 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocycles by Diene Syntheses, IV1). - Orientation in the Diene Synthesis of N-Trichloroethylidene-p-toluenesulfonamideBy Diels-Alder reaction, N-trichloroethylidenetosylamide (2) yields, with 1-substituted dienes, the 6-substituted 1-tosyl-2-trichloromethyl-1,2,3,6-tetrahydropyridines 3; with 2-substituted dienes, the corresponding 4-substituted adducts are formed. The general orientation phenomena in the Diels-Alder reaction of heterodienophiles are discussed.
    Notes: Bei der Diels-Alder-Reaktion von N-Trichloräthyliden-tosylamid (2) mit 1-substituierten Dienen entstehen 6-substituierte, mit 2-substituierten Dienen dagegen 4-substituierte 1-Tosyl-2-trichlormethyl-1.2.3.6-tetrahydro-pyridin-Derivate (3). Die Orientierungsphänomene bei der Diels-Alder-Reaktion mit Heterodienophilen werden allgemein diskutiert.
    Additional Material: 1 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1973 (1973), S. 650-658 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocycles by Diene Synthesis, IV1). - 3-Hydroxypyrroles from Diels-Alder Adducts of Nitroso CompoundsThe methyl 2-acetoxy-4-aryl-1,3-butadiene-1-carboxylates 1 are synthesized and then allowed to react with nitrosobenzenes 2 to give mixtures of the Diels-Alder adducts 3 and 4. The isomer ratio 3 : 4 is dependent on the nature of the aryl substituents in 1 and 2; this dependence may be explained by the mechanism of the cycloaddition. - The adducts 3 are converted into 3-hydroxypyrrole-2-carboxylic acid derivatives by chromatography on silica.
    Notes: 2-Acetoxy-4-aryl-1,3-butadien-1-carbonsäure-methylester 1 werden synthetisiert und mit Nitrosobenzolen 2 zu Gemischen der isomeren Diels-Alder-Addukte 3 und 4 umgesetzt. Die Abhängigkeit des Isomerenverhältnis 3 : 4 von den Arylsubstituenten in 1 und 2 ist aus dem Mechanismus der Cycloaddition verständlich. - Die Addukte 3 lassen sich durch Chromatographie an Kieselgel in 3-Hydroxypyrrol-2-carbonsäurederivate 5 überführen.
    Additional Material: 3 Tab.
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  • 6
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Butadienylsulfonium Salts, II1)  -  Reaction of trans-(1,3-Butadienyl)dimethylsulfonium Halides with Bases**)Some reactions of butadienylsulfonium salts with alkali hydroxide, thiophenolate, and alkoxides are described. With catalytic amounts of alkoxide in alcoholic solution the dienylsulfonium salts 1a, b yield (2,4-dialkoxybutyl)sulfonium salts 7 and/or (alkoxybutenyl)-sulfonium salts 4 and 6. At high alkoxide concentration the main products are substituted butenyl sulfides 9, formed by [2,3]-sigmatropic rearrangement of the 4-ylides. Under the same conditions (2,3-dimethyl-1,3-butadienyl)dimethylsulfonium bromide (1c) rearranges to 2-methyl-3-methylene-5-methylthio-1-pentene (16).
    Notes: Einige Reaktionen der Butadienylsulfoniumsalze 1 mit Alkalihydroxid, Thiophenolat und Alkoholaten werden beschrieben. Mit katalytischen Mengen Alkoholat ergeben die Dienylsulfoniumsalze 1a, b in alkoholischer lösung die (2,4-Dialkoxybutyl)sulfoniumsalze 7 und/oder die (Alkoxybutenyl)sulfoniumsalze 4 und 6. Bei hohen Alkoholatkonzentrationen werden durch [2,3]-sigmatrope Umlagerung der 4-Ylide hauptsächlich die substituierten Butenylsulfide 9 gebildet. (2,3-Dimethyl-1,3-butadienyl)dimethylsulfoniumbromid (1c) liefert unter diesen Bedingungen 2-Methyl-3-methylen-5-methylthio-1-penten (16).
    Additional Material: 1 Ill.
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  • 7
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aliphatic α-Substituted Nitroso Compounds, I. Chemistry and Stereochemistry of α-Substituted 3-Nitrosomenthanes3-Nitroso-3-halo- or 3-nitroso-3-acyloxymenthanes 2 are prepared. Their isomerisation to the diastereoisomeric 6 and the substitution reactions of the halogen derivatives are investigated. UV- and NMR-spectra as well as CD-curves of the nitrosomenthanes 2 and 6 are used to obtain information about the stereochemistry of these compounds (tables 1-4, figures 1 and 2).
    Notes: 3-Nitroso-3-halogen- bzw. 3-Nitroso-3-acyloxy-menthane 2 werden dargestellt. Ihre Isomerisierung zu den Diastereomeren 6 und die Substitution des Halogens werden untersucht. UV- und NMR-Spektren sowie CD-Kurven der 3-Nitroso-menthane 2 und 6 werden zu Aussagen über die Stereochemie benutzt (Tabb. 1-4, Abb. 1 und 2).
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 762 (1972), S. 93-105 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with N-Sulfinyl Compounds, XI1). - Orientation in the Diene Synthesis of N-Sulfinyl-p-toluene SulfonamideThe 2-substituted dienes 2 yield by Diels-Alder reaction with N-sulfinyltosylamide (3) only the 5-substituted 3,6-dihydro-1,2-thiazine 1-oxides 6. 1-tert.-Butylbutadiene (1e) and methyl vinylacrylate (1f) give with 3 only the 6-substituted adducts 4e or 4f. With 1.3-pentadiene (1d) and with the 1-arylbutadienes 1a-c the 3- or 6-substituted adducts 5 or 4 are formed, depending on the reaction temperature. The adducts of the 1-substituted dienes 1 with 3 are mixtures of diastereoisomers.
    Notes: Die 2-substituierten Diene 2 setzen sich bei der Diels-Alder-Reaktion mit N-Sulfinyl-p-toluolsulfonamid (3) nur zu den 5-substituierten 3.6-Dihydro-1.2-thiazin-1-oxiden 6 um. 1-tert.-Butyl-butadien (1e) und Vinylacrylsäuremethylester (1f) reagieren mit 3 dagegen zu den 6-substituierten Addukten 4e bzw. f, während 1.3-Pentadien (1d) sowie die 1-Aryl-butadiene 1a-c in Abhängigkeit von der Reaktionstemperatur die 3- bzw. 6-substituierten Addukte 5 bzw. 4 ergeben. Die Addukte von 3 mit den 1-substituierten Dienen 1 sind Diastereomerengemische.
    Additional Material: 6 Tab.
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  • 9
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Butadienylsulfonium Salts, I. - Preparation of trans-1-Dialkylsulfonio-1.3-butadiene halides from 1,4-Bis[dialkylsulfonio]-2-butene dihalides1,4-Bis[dialkylsulfonio]-2-butene dihalides 5 (synthetized by two ways) are used to prepare trans-1-Dialkylsulfonio-1,3-butadiene halides 6. The conversion of 6 to trans-1-Alkylthiodienes, in solution and by pyrolysis, is described.
    Notes: Aus den auf zwei Wegen erhältlichen 1.4-Bis-[dialkylsulfonio]-2-buten-dihalogeniden 5 werden die trans-1-Dialkylsulfonio-1.3-butadien-halogenide 6 dargestellt. Deren Übergang in trans-1-Alkylmercapto-diene in Lösung und durch Pyrolyse wird beschrieben.
    Additional Material: 1 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1973 (1973), S. 1457-1466 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,6-Cyclization of Phenyliminomethylimino Cumulenes: Formation of Quinazoline DerivativesThe reaction of N2-arylamidines 1 with N-tosylisocyanodichloride gives the quinazoline derivatives 5. Addition of the compounds 1 to chloral followed by treatment with acetic anhydride yields the quinazolines 9, 10 and 13.
    Notes: Die Reaktion von N2-Arylamidinen 1 mit N-Tosylisocyandichlorid 4 führt zu den Chinazolinderivaten 5. Bei der Umsetzung der Verbindungen 1 mit Chloral und nachfolgender Behandlung mit Acetanhydrid werden die Chinazoline 9, 10 und 13 erhalten.
    Additional Material: 1 Tab.
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