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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 2319-2325 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organosulfur Compounds, VII. Photochemical α-Cleavage of S-p-Tolyl Thiobenzoates in SolutionBy photolysis of some tolylesters 1 of donorsubstituted thiobenzoic acids the S-aroyl bonds are cleaved. Aroyl and thiyl radicals, formed through α-cleavage, are stabilized by aldehyde (2) and disulfide formation (4. In three cases, benzils (3) are also formed. Thia-photo-Fries rearrangements are not observed. Photopolymerizations of vinyl monomeres in film and in block are initiated by the studied α-ketosulfides 1.
    Notes: Bei der Photolyse von Tolylestern 1 donatorsubstituierter Thiolbenzoesäuren werden die S-Aroyl-Bindungen gespalten. Die durch α-Spaltung gebildeten Aroyl- und Thiylradikale stabilisieren sich durch Aldehyd- (2) bzw. Disulfidbildung (4). In drei Fällen entstehen auch Benzile (3). Thia-Photo-Fries-Umlagerungen werden nicht beobachtet. Photopolymerisationen von Vinylmonomeren im Film und im Block werden durch die untersuchten α-Ketosulfide 1 initiiert.
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  • 12
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organosulfur Compound, XI. Synthesis of 13-3-Oxathiol-spirofuranones and Furanone-spirodihydrothiopyrans from 4-Thioxotetrahydrofuran-3-onesHeterocyclic, non-enolisable α-oxo-thioketones of furan-type 9 have been prepared for the first time. These highly unstable compounds undergo dimerisation and subsequent elimination of sulfur to give 1,3-oxathiol-spirofuranones 11. In competition with this process reaction with the eliminated active sulfur can occur to yield a dispiro-1,2,4-trithiolan 10a. In the presence of dimethylbutadiene the new α-oxo-thioxofurans 9 react according to the Diels-Alder principle to form the furanone-spirodihydrothiopyrans 13. The reaction mechanisms are discussed.
    Notes: Es werden erstmals heterocyclische, nicht enolisierbare α-Oxo-thioketone vom Furantyp (9) hergestellt, die außerordentlich instabil sind und unter Dimerisierung mit anschließender Schwefeleliminierung reagieren, wobei die bisher unbekannten 1,3-Oxathiol-spirofuranone 11 entstehen. In Konkurrenz hierzu kann Reaktion mit dem bei der Fragmentierung gebildeten aktiven Schwefel unter Bildung eines Dispiro-1,2,4-trithiolans (10a) eintreten. In Gegenwart von Dimethylbutadien reagieren die neuen α-Oxo-thioxo-furane 9 ausschließlich nach dem Diels-Alder-Prinzip unter Bildung der Furanon-spirodihydrothiopyrane 13. Die Reaktions-mechanismen werden diskutiert.
    Additional Material: 2 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 3745-3746 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Tellurium Compounds, IV: An Improved Synthesis of TelluropheneTellurophene (1) is synthesized in good overall yields in an improved synthesis using bis(trimethylsilyl)-1,3-butadiyne and sodium telluride generated in situ from tellurium and sodium formaldehyde sulfoxylate.
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  • 14
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Sulfur Compounds, LX. The Formation of Methylene Bisxanthogenates by Action of Diaryldiazomethanes on Dialkyl Xanthogen Disulfides and their FragmentationS - S-Insertion reactions were observed when diaryldiazomethanes 1 were allowed to react with dialkyl xanthogen disulfides 2 (see (2)). Identification of the reaction products asmethylene bisxanthogenates 3 was confirmed by additional preparation of 3 by reaction of the gem. dichlorides 4 with potassium xanthogenates 5 (see (3)) as well as by the n.m.r. spectra. Dibenzyl-, dibenzoyl-disulfides, and tetramethyl-thiuramdisulfide do not undergo an analogous reaction with diphenyldiazomethane. The bisxanthogenates 3 decompose at room temprature in the solid state and in solution to give the corresponding thioketones (see (4)-(6)). The diarylderivatives 3a and 3e, however, are stable in the solid state. The fragmentation is facilitated by using ethanol, dimethylformamide or pyridine as solvents. The mechanism of the fragmentation is discussed.
    Notes: Die unter S - S-Insertion verlaufenden Reaktionen der Diaryldiazomethane 1 mit den Dixanthogenen 2 führen gemäß (2) zu den Diarylmethylen-bis-xanthogenaten 3, deren Konstitution durch direkten Vergleich mit den aus den gem. Dichloriden 4 und den Kaliumxanthogenaten 5 nach (3) gewonnenen Verbindungen sowie durch die NMR-Spektren sichergestellt wurde. Dibenzyl- und Dibenzoyldisulfid sowie Tetramethyl-thiuramdisulfid lassen sich mit Diphenyldiazometan nicht analog umsetzen. Die Bis-xanthogenate 3 fragmentieren bei Raumtemp. in Festsubstanz mit Ausnahme der Diphenyl-Derivate 3a und 3e, in Lösungsmitteln jedoch ohne Ausnahme, in die entsprechenden Thioketone, siehe Gleichungen (4)-(6). Wärmezufuhr und Lösungsmittel wie Äthanol, DMF oder Pyridin begünstigen die Fragmentierung, deren Mechanismus diskutiert wird.
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  • 15
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organosulfur Compounds, VIII. Formation of Thiophenes by Pyrolysis of Dihydrothiopyrans, Reactions of Diels-Alder Adducts from Thiofluorenone and 1,3-Butadienes under Heating and Electron-Impact ConditionsThiofluorenone (1) reacts with 2,3-dimethyl- and 2,3-diphenyl-1,3-butadienen to give the Diels-Alder adducts 2a and 2b respectively. The adducts 2a and 2b, thermally stable either in solution or in the solid, decompose under electron-impact conditions according to the Retro-Diels-Alder principle. The pyrolysis of the spiro-dihydrothiopyranes 2 gives the thiophenes 3 and 4. The constitution of the new compounds 2, 3 and 4 finds confirmation from their mass, 1H-and 13C-n.m.r. spectra.
    Notes: Aus Thiofluorenon (1) und 2,3-Dimethyl-bzw. 2,3-Diphenyl-1,3-butadien entstehen die Diels-Alder-Addukte 2a bzw. 2b, die thermisch nicht  -  weder in Lösung noch in Substanz -, wohl aber unter Elektronenstoß nach dem Retro-Diels-Alder-Prinzip zerfallen. Die Pyrolyse der Spiro-dihydrothiopyrane 2 in Substanz liefert die Thiophene 3 und 4. Die Konstitutionsermittlung der neuen Verbindungen 2, 3 und 4 beruht u. a. auf Massen-, 1H-NMR-und 13C-NMR-Spektren.
    Additional Material: 2 Tab.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2744-2749 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Sulfur Compounds, XXXVI. Synthesis of 1,3-Oxathioles from Monothiobenzils and DiaryldiazomethanesFour 4,4′-disubstituted monothiobenzils 2a-d have been synthesized. They react with diaryl-substituted diazomethanes 3a-c in solution to form tetraaryl-substituted 1,3-oxathioles 4a-g accompanied by evolution of nitrogen. The 1,3-oxathioles 4a and d have been oxidized with m-chloroperbenzoic acid furnishing the corresponding S-oxides 5a and b.
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 866-868 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Note on the Preparation of scyllo-InositolA simplified synthesis of scyllo-inositol (4) from myo-inositol (1) via the pentaacetate of myo-inosose (3) is described.
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  • 18
    ISSN: 0170-2041
    Keywords: Benzenepentamine ; Benzopyrazines ; N-Heterocycles ; Nitroarenes ; Pyrazinoquinoxalines ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzolpentamin - leichter Zugang und Gebrauch in einfachen Pyrazinochinoxalin-SynthesenFür das nach 60 Jahren wiederentdeckte Benzolpentamin (6) wird ein einfacher Syntheseweg beschrieben, der das sehr empfindliche, farblose 6 in methanolischer Lösung nahezu quantitativ liefert. Mit den zwei maskierten Formen A und B des Glyoxals kondensiert 6 selektiv und in guten Ausbeuten unter Bildung zweier Amino-substituierter Pyrazinochinoxaline: 7a mit Phenanthren bzw. 8a mit Anthracen-artiger Struktur. Weniger selektiv reagiert das α-Diketon Benzil mit 6, wobei die entsprechenden Tetraphenyl-Derivate 7b und 8b der beiden Pyrazinochinoxalin-Ringsysteme erhalten werden. Das vormals unbekannte, bei Reduktionen von 1,3,5-Trinitrobenzoltriamin neben Benzolhexamin erhaltene Nitrobenzolpentamin (9) wird ebenfalls vorgestellt. Die Strukturen dieser zwei Multiamine wurden aufgrund spektroskopischer Daten von ihren Kondensationsprodukten mit α-Di ketonen abgeleitet, z. B. im Falle des neuen Pentamins 9 von seinen ersten Derivaten 7c-e des Pyrazino[2,3-f]chinoxalins.
    Notes: Benzenepentamine (6) has been rediscovered after about 60 years. A simple and very efficient synthetic route is described which yields the very sensitive, colourless 6 in methanolic solution in nearly quantitative yield. Condensations of 6 with two masked forms A and B of glyoxal conveniently lead to two types of amino-substituted pyrazinoquinoxalines, one with an angular phenanthrene-type topology (7a), or one with the linear anthracene-type structure (8a), respectively, with acceptable yields. The α-diketone benzil also reacts with 6, but less selectively, forming the corresponding tetraphenyl derivatives 7b an 8b of both these heterotricyclic ring systems. The heretofore unknown nitrobenzenepentamine (9), formed in addition to benzenehexamine in reduction reactions of 1,3,5-trinitrobenzenetriamine, has also been obtained. Based on spectroscopic data, the structures of these two multiamines have been deduced from their condensation products with α-diketones, in the case of the new pentamine 9 from its first derivatives 7c-e of pyrazino[2,3-f]quinoxaline.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 2043-2056 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Photochemistry, XXXIV.  -  S-Esters of Thiophencarbothioic Acids. Synthons for Thienothiochromones and ThienoazathiochromonesOn UV irradiation in benzene S-aryl esters 4c - e, 9a - c of 3-bromothiophen-2- and thiophen-3-carbothioic acid yield thienobenzothiopyranones 7 and 11, respectively. The corresponding S-pyridyl esters 4f, g, 9e, f of these thiophencarbothioic acids give the thienothiopyranopyridinones 8a, b and 14a, b, respectively, which are new heterocyclic ring systems. - The constitutional requirements for the formation of these heterocycles by photocyclization via thiolester-thiopyrone-transformation are discussed. Only 9a photocyclizes in a twofold manner with formation of thienobenzothiopyranone 11a and thienothiocoumarin 12. - Compound 12, thiophen-2-carbaldehyde 5c, and S-ester 6 are products of intra- or intermolecular aromatic photosubstitutions of halogen by phenyl. - The majority of S-esters 4 and 9 also yield thiophenecarbaldehydes 5 or 10, respectively, which can even be main products of the photoreactions.
    Notes: Die S-Arylester 4c - e, 9a - c der 3-Bromthiophen-2-carbonsäuren und Thiophen-3-thiocarbon-säuren liefern bei UV-Bestrahlung in Benzol die Thienobenzothiopyranone 7 bzw. 11. Entsprechend erhält man aus den S-Pyridylestern 4f, g, 9e, f dieser Thiophenthiocarbonsäuren die Thienothiopyranopyridinone 8a, b bzw. 14a, b, die neue heterocyclische Ringsysteme darstellen. - Die konstitutionellen Voraussetzungen für die Bildung dieser Heterocyclen durch Photocyclisierung über Thiolester-Thiopyron-Transformation werden diskutiert. Lediglich 9a photocyclisiert in zweifacher Weise zum Thienobenzothiopyranon 11a und zum Thienothiocumarin 12. - Die Verbindung 12, der Thiophen-2-carbaldehyd 5c und der S-Ester 6 sind Produkte intra- oder inter-molekularer aromatischer Photosubstitutionen von Halogen gegen Phenyl. - Die Mehrzahl der S-Ester 4 und 9 liefern bei UV-Bestrahlung auch die Thiophencarbaldehyde 5 bzw. 10 als Neben-oder Hauptprodukte.
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1604-1619 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organosulfur Compounds, L. - 2H-Thiopyrans and Dihydro-2H-thiopyrans, Synthons for Thiophenes2H-Thiopyran derivatives yield thiophenes on pyrolysis at 240-260°C. The influence of substitution in positions 3 to 6 of the 2H-thiopyrans on these new thermal rearrangement and fragmentation reactions is dealt with, and some proposed mechanisms are discussed in detail. A novel three-step synthesis of thiophenes from carbonyl compounds via the corresponding thiones, their [4 + 2]-cycloaddition with 1,3-dienes with formation of dihydro-2H-thiopyrans and subsequent thermal conversion is described. In this reaction sequence, whose scope and limitations are outlined, the thiocarbonyl compound contributes the sulfur and the 1,3-diene the carbon skeleton of the desired thiophenes.
    Notes: 2H-Thiopyran-Derivate liefern durch Pyrolyse bei 240- 260°C Thiophene. Einflüsse von Substitutionen in 3- bis 6-Stellung der 2H-Thiopyrane auf diese neuen thermischen Umlagerungs- und Fragmentierungsreaktionen sowie mechanistische Vorstellungen darüber werden ausführlich diskutiert. Unsere Ergebnisse beschreiben ein neues, dreistufiges Synthesekonzept für Thiophene aus Carbonylverbindungen über entsprechende Thione, deren [4 + 2]-Cycloadditionen mit 1,3-Dienen zu Dihydro-2H-thiopyranen und anschließende thermischer Umwandlung. Die Thiocarbonylverbindungen liefern in diesem Reaktionablauf - dessen Grenzen herausgestellt werden - den Schwefel und die 1,3-Diene das Kohlenstoffgerüst der gewünschten Thiophene.
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