SYNTHESIS OF NOVEL 2-SUBSTITUTED-1,3,4-THIADIAZOLES

Nem 2-monosubstituted and 2,2-disubstituted 2,3-dihydro-3,5-diphenyl-1 ,3,4-thiadiazoles (2) were synthesized by the reaction of N'-phenylthi obenzoylhydrazide with aliphatic, aromatic and heterocyclic aldehydes and ketones in the presence of trimethylsilyl chloride in benzene, The reaction proceeded smoothly to afford the corresponding 1,3,4-thiadia zoles (2a-2j) in excellent yields (84-96%) except for a few cases, suc h as the 5-methyl-2-furfural and 2-acetylthiophene systems, 3-Dihydro- 2,2-dimethyl-3,5-diphenyl-1,3,4-thiazole (2f) showed curative activity against powdery mildew of wheat.