Thiophene ring-opening reactions v. expedient synthesis of 1,3,4-thiadiazoline─sulfanyl[1,3]thiazin-4-one hybrids †

Abstract: The preparation of 6-chloro-5-nitrothieno[3,2-e][1,3]thiazin-4-one incorporating 2-(N-morpholinyl) moiety, is achieved via a conventional route. Interaction of the latter substrate with a set of N'-(aryl) benzothiohydrazides 1a-f, in the presence of triethylamine, led to a thiophene ring-opening process with the consequent generation of the respective thiolate salts 8a-f. Alkylation of the latter, using methyl iodide or allyl chloride, generated the respective novel 1,3,4-thiadiazoline–6-sulfanyl-1,3-thiazin-4-one hybrids, the structures of which were verified by HRMS and NMR spectral data.