Chemical and Pharmaceutical Bulletin
Online ISSN : 1347-5223
Print ISSN : 0009-2363
ISSN-L : 0009-2363
Studies on Isoxazoles. XI. Pyrolyses of 4-Isoxazolin-3-thiones
SOJI SUGAIKAZUO TOMITA
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Keywords: sulfur radicals
JOURNAL FREE ACCESS

1980 Volume 28 Issue 1 Pages 103-109

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Abstract
Novel pyrolysis reactions of 4-isoxazolin-3-thiones (X) are described, affording two regioisomeric 1, 4-dithiins (III, IV) and thioacetamides (XI). Among the thioacetamides, N-methylbenzoylthioacetamide (XIe) was identical with an authentic sample prepared by the reduction of 2-methyl-5-phenyl-4-isoxazolin-3-thione (Xe) with thiophenol. The structures of the dithiins were deduced from the physicochemical data, especially the shielding and deshielding effects in the NMR spectra. A mechanism for the reactions is proposed by analogy with the thermal isomerization of 3-isoxazolones into 2-oxazolones. In order to account for the formation of the isomeric dithiins, a thiirene intermediate (II) was assumed to be involved in the reaction pathway.
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© The Pharmaceutical Society of Japan
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