2-BUTENOIC ACID, 4-((5-METHYL-1,3,4-THIADIAZOL-2-YL)AMINO)-4-OXO-, METHYL ESTER 4-((5-Methyl-1,3,4-thiadiazol-2-yl)amino)-4-oxo-2-butenoic acid methyl ester 81542-43-0 BRN 5952018