Acylation of N′-arylbenzothiohydrazides and of their N′-acyl-derivatives; 2-acylalkylidene-3-aryl-5-phenyl-2H-1,3,4-thiadiazolenes and related compounds

Abstract
Reactions of N′-arylbenzothiohydrazides and of their N-acyl-derivatives with carboxylic anhydrides under various sets of conditions are shown to lead to 2-acylalkylidene-3-aryl-5-phenyl-2H-1,3,4-thiadiazolenes. The probable mechanism of formation of these compounds via the corresponding 2-alkylidenethiadiazolene as intermediate is discussed.