Hydrochloric Acid → 4-(2-(Methylthio)pyrimidin-4-YL)-1H-pyrazol-5-amine

Participants

Reaction Steps

A suspension of 2-(2-(methylthio)pyrimidin-4-yl)-3-oxopropanenitrile (5) (100 g, 0.52 mol), NH2NH2—H2O (85%, 31.2 g, 0.62 mol) and conc. HCl (60 mL) in ethanol (1 L) was stirred at reflux for 5 h. After cooled to room temperature, the mixture was concentrated in vacuum, and the residue was washed with ether (200 mL×3) and suspended in H2O (200 mL). The mixture was basified with saturated aq. Na2CO3 to pH 9 and the precipitate was collected. The solid was washed with H2O (100 mL×3) and ether (200 mL×3), then dried in vacuum to give 4-(2-(methylthio)pyrimidin-4-yl)-1H-pyrazol-5-amine (6) (56.8 g, 51.8%) as a yellow solid. 1H NMR (400 MHz, CD3CN): δ 8.295 (d, 1H), 7.826 (s, 1H), 7.101 (d, 2H), 5.800 (d, 1H), 2.586 (s, 3H).

Provenance & Evidence