Abstract
(Z)-2-Benzylidene-2,3-dihydro-3,5-diphenyl-1,3,4-thiadiazole (1 a) undergoes slow hydrolysis during long term storage (ca eleven years) to N′-phenacetyl-N′-phenyl-N-thiobenzhy-drazide (2a); the 2-(4-methoxybenzylidene) derivative behaves similarly.