Studies on Isothiazoles. IV. A New Synthetic Route to 4-Cyanoisothiazoles

Abstract
4-Cyanoisothiazoles have been prepared by a novel procedure which comprises the reacreaction of β-cyano enamines with thionyl chloride or sulfur monochloride. The reaction proceeds favorably in nonpolar solvents or in the absence of solvent. However, the cyclization did not occur in dimethylformamide and instead an amidine derivative was isolated. The preparations of the corresponding isothiazole-4-carboxylic acids are also described briefly.