Phenylhydrazine → 3-Ethyl-1-phenyl-1H-pyrazol-5-amine

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of 3-oxopentanenitrile (19.42 g, 0.20 mol) and phenylhydrazine (23.62 g, 0.20 mol) in ethanol (200 mL) was heated at 90° C. for 15 h. The reaction mixture was quenched with water and extracted with dichloromethane. The combined dichloromethane layers were dried over magnesium sulfate, concentrated under reduced pressure, and dried under vacuum to afford the light yellow oil which was purified by silica gel flash column chromatography (eluting with a mixture of 20% ethyl acetate in petroleum ether). The obtained solid was recrystallized from a mixture of 10% petroleum ether in ethyl acetate, to afford 3-ethyl-1-phenyl-1H-pyrazol-5-amine (14 g, 37% over two steps) as a yellow solid. 1H NMR (400 MHz, DMSO-d6) δ 7.57-7.59 (m, 2H), 7.43-7.46 (m, 2H), 7.27 (m, 1H), 5.36 (s, 1H), 5.26 (s, 2H), 2.45 (q, J=7.6 Hz, 2H), 1.15 (t, J=7.6 Hz, 3H); LC-MS (ESI) m/z 188 (M+H)+.

Provenance & Evidence