Ethanol → ethyl 3-(5-amino-3-tert-butyl-1H-pyrazol-1-yl)benzoate

Participants

Reaction Steps

A mixture of 3-hydrazino-benzoic acid hydrochloride (200 g, 1.06 mol) and 4,4-dimethyl-3-oxo-pentanenitrile (146 g, 1.167 mol) in ethanol (2 L) was heated to reflux overnight. The reaction solution was evaporated under reduced pressure. The residue was purified by column chromatography to give 3-(5-amino-3-t-butyl-pyrazol-1-yl)-benzoic acid ethyl ester (116 g, 40%) as a white solid together with 3-(5-amino-3-t-butyl-pyrazol-1-yl)-benzoic acid (93 g, 36%). 3-(5-amino-3-t-butyl-pyrazol-1-yl)-benzoic acid and ethyl ester: 1H NMR (DMSO-d6): 8.09 (s, 1 H), 8.05 (brd, J=8.0 Hz, 1 H), 7.87 (br d, J=8.0 Hz, 1 H), 7.71 (t, J=8.0 Hz, 1 H), 5.64 (s, 1 H), 4.35 (q, J=7.2 Hz, 2 H), 1.34 (t, J=7.2 Hz, 3 H), 1.28 (s, 9H).

Provenance & Evidence