Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazine and 1,3,4-Thiadiazine from Substituted Acetophenones and Acid Hydrazides Using [Hydroxyl(tosyloxy)iodo]benzene

A novel and direct method for the efficient synthesis of 2,5-disubstituted 1,3,4-oxadiazines from the reactions of [hydroxy(tosyloxy)iodo]benzene with substituted acetophenones, followed by the treatment with acid hydrazide and K2CO3, is reported. The methodology is also extended to the synthesis of 5-aryl-6H-1,3,4-thiadiazin-2-amine by using thiosemicarbazide under similar experimental conditions.