Hydrochloric Acid → 3-Amino-1-(propan-2-yl)-1H-pyrazole-4-carbonitrile

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Reaction Steps

A mixture of Intermediate 2-((2-benzylidene-1-isopropylhydrazinyl)-methylene)malononitrile (9.42 g, 40 mmol), concentrated hydrochloric acid (5 ml), and ethanol (50 ml) was heated at reflux for 20 min. The reaction mixture was concentrated and ether (50 ml) was added. The mixture was sonicated, then the upper ether layer was discarded. To the residue was added 20 ml of 5N aqueous sodium hydroxide solution and the mixture was extracted with dichloromethane (3×). The organic layers were combined, dried over sodium sulfate, filtered, and concentrated. The residue was purified by silica gel column chromatography (1:1 hexanes/ethyl acetate eluant) to afford 3-amino-1-isopropyl-1H-pyrazole-4-carbonitrile as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ 8.09 (s, 1H), 5.51 (s, 2H), 4.22 (m, 1H), 1.31 (d, J=7 Hz, 6H); MS m/z 151.2 (M+1).

Provenance & Evidence