Cyclisierung von 3-Acylmethylthio-4-cyan-2H-isothiazol-5-thionen

摘要

The title compounds2cyclize on mild conditions to the intermediate 7-cyano-thiazolo3,2-bisothiazole-6-thiones3which are converted immediately into the 1,2,4-trithiolane-3,5-diylidene-(thiazole-2-yl)-acetonitriles4accompanied by extrusion of sulphur. The cyclization of the 4-cyano-5-methylthio-3-phenacylthio-isothiazole (6) yields the 7-cyano-6-methylthio-thiazolo3,2-b isothiazoliumsalt7which undergoes reductive ring opening by hydrazine hydrate to yield methyl (4-phenyl-thiazolin-2-ylidene)-cyanodithioacetate (8).