Abstract Nitrosation of hydrazino substituted thiazole-4-acetates has been shown to occur on the ring, rather than the α-methylene carbon, as previously reported. Thus nitrosation of ethyl 2-isopropylidenehydrazono-, 2-benzylidenehydrazono-, 2-(2-benzoylhydrazino)-, and 2-(2-acetylhydrazino) thiazole-4-acetates yielded the corresponding 2-hydrazino-4- carbethoxymethylidene-4, 5-dihydrothiazoline-5-oximes. Basic hydrolysis of the thiazoline ...
