- Electroreduction of Organic Compounds, 19. Formation of Benzoanellated Sulfur Heterocycles by Intramolecular Cathodic Cyclization of Dithiocarboxylic Esters
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Cathodic reduction of aryl (3) and benzyl (5) dithiopivaloates and related dithioesters with leaving groups at the benzene ring or a side chain yield the sulfur heterocycles 23, 30 - 32, and 34 depending on the nature of the starting material and the reaction conditions.In the case of the α-oxo-dithioester 22, thioindigo (44) is formed. - The corresponding thioamides 14, 16, and 18 show a strong tendency to reductive dehalogenation but the S,N-heterocycles 38 and 39 are also formed in minor amounts. - The formation of the rearranged products 29 - 32, and 34 isdiscussed in terms of C,S-splitting in the primarily formed radical anion and subsequent C,C-coupling of the fragments and follow-up reactions.Key Words: Dithiopivaloates, S-aryl, S-benzyl / Electroreduction
- Gade, Thomas,Streek, Michael,Voss, Juergen
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p. 127 - 142
(2007/10/02)
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- Chemotherapeutic agents
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A method of treating or preventing viral infections, in particular rhinovirus infections comprising the administration of an effective amount of a 2-phenyltetralin derivative or a heterocyclic analogue thereof. Pharmaceutical compositions containing these compounds, and some novel compounds are also disclosed.
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- Synthesis of the Benzotricyclo2,7>heptene Ring System via the Intramolecular -Cycloaddition Reaction of Some Cyclopropene Derivatives
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The photo and thermal reactions of a number of 1,2-diphenyl-3-methyl-3-(o-vinylphenyl)-substituted cyclopropenes have been studied.The thermolysis of these systems gave substituted benzotricyclo2,7> heptenes in good yield by means of a novel intramolecular cycloaddition.The sensitized di-?-methane photorearrangement of several substituted benzonorbornenes was used to independently synthesize the thermal cycloadducts.The observed regiospecificity of the rearrangement is understandable in terms of formation of the most stable diradical intermediate.In contrast to the thermal results, the photosensitized irradiation afforded a mixture of two products.In addition to the cycloadduct, a new compound was isolated whose formation involves attack of the ortho position of the triplet state on the terminal vinyl carbon followed by diradical coupling and subsequent rearomatization.Thermolysis or sensitized photolysis of several unsymmetrically substituted 1,3-diphenyl-2-methyl-2-(o-vinylphenyl)cyclopropenes afforded related cycloadducts.With these systems, the -cycloaddition reaction is highly regiospecific and involves bonding from the cyclopropene carbon bearing the methyl group onto the terminal vinyl carbon.The silver ion and singlet excited-state behavior of several substituted cyclopropenes was also studied, and the results obtained were compared to the reactions which occur on thermolysis or sensitized photolysis.
- Padwa, Albert,Rieker, William F.,Rosenthal, Robert J.
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p. 4446 - 4456
(2007/10/02)
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