Synthesis, X‐ray crystal structure and biological activities of α‐phenoxyl‐1,2,3‐thiadiazoleacetamide

The annelation of 1,2,3‐thiadiazole rings was accomplished by the reaction of N ‐acylhydrazone 2a bearing an adjacent α‐methyl with thionyl chloride to give α‐chloro‐ N ‐methyl‐1,2,3‐thiadiazole‐4‐acetamide 4 and was demonstrated by the X‐ray crystal structure of its derivative 5a. A novel series of α‐substituted phenoxy‐ N ‐methyl‐1,2,3‐thiadiazole‐4‐acetamide 5 were synthesized through the reaction of the compound 4 and phenols. The results of bioassays show that the title compounds exhibit good anti‐HBV activities. The crystal of compound 5a , N ‐methyl‐α‐2‐bromophenyl‐1,2,3‐thiadiazole‐4‐acetamide, has been prepared and determined by X‐ray diffraction.