Reactivity of (2-methylsulfanyl-4-oxo-6-phenyl-4h-pyrimidin-3-yl)-acetic acid methyl ester towards hydrazine hydrate and benzylamine

The title ester 1 reacted with hydrazine hydrate to give hydrazide 2, which underwent intramolecular cyclization to yield 1‐amino‐7‐phenyl‐1H‐imidazo[1,2‐a]pyrimidine‐2,5‐dione (3) or took place in a substitution reaction with benzylamine to form N‐benzyl‐2‐(2‐benzylamino‐4‐oxo‐6‐phenyl‐4H‐pyrimidin‐3‐yl)‐acetamide (4). The reaction of ester 1 with benzylamine gave corresponding amide 7, disubstituted derivative 4 or 1‐benzyl‐7‐phenyl‐1H‐imidazo[1,2‐a]pyrimidine‐2,5‐dione (8) depending on the reaction conditions.