Studies on heterocyclic chemistry. Part 26. The ring transformation of 3-acylthio-4-aryl-3-isothiazoline-5-thiones to benzo[b]- and naphtho[2,1-b]-thiophens with an acylimino-group at C-2 via the 2-arylethanethioamide derivatives

Abstract

The oxidative cyclisation, by halogen, of 2-arylethanethioamide derivatives {dialkyl 2-[2-(acylamino)-1-aryl-2-thioxoethylidene]-1,3-dithiole-4,5-dicarboxylates and their related ketones}, which are synthesized from the reaction of 3-acylthio-4-aryl-3-isothiazoline-5-thiones with reactive acetylenes, to give benzo[b]- and naphtho[2,1-b]-thiophens with an acylimino-group at C-2 in useful yields, is described.