Synthesis of Two Isomeric Thiadiazine and Thiazole Derivatives from a Hydrazonoyl Halide

Thiadiazine and thiazoles have attracted importance due to their broad applicability as biologically active compounds. New thiadiazines and thiazoles are prepared via the simple reaction of an α-haloketohydrazonoyl with thiocarbohydrazone derivatives in a basic medium under reflux. A S-alkylated intermediate forms through nucleophile substitution involving the hydrazonoyl halogen and thiocarbohydrazone thiol. In situ cyclization via the condensation between the carbonyl and NH2 or NH moieties of the intermediate forms 1,3,4-thiadiazine and thiazole derivatives, respectively. This method employs inexpensive, commercially available reagents and facile reaction conditions to afford novel thiadiazine/thiazole derivatives in good yields.