Acetic Acid → 4-(5-Amino-3-tert-butyl-pyrazol-1-yl)-benzoic acid

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Reaction Steps

A mixture of 4,4-dimethyl-3-oxo-pentanenitrile (4.52 g, 36.15 mmol), 4-hydrazinobenzoic acid (5.00 g, 32.86 mmol), and acetic acid (2 mL) in EtOH/THF (1:1) was refluxed for 16 h. After cooling, the solvent was concentrated at reduced pressure, and the crude was re-dissolved in EtOAc. The organic layer was washed with aqueous saturated Na2CO3 solution and brine, dried over MgSO4, filtered, and concentrated to half its volume. The resulting residue was filtered, and the solids were washed with cold EtOAc and dried under high vacuum to afford the title compound as a white solid (8.4 g, 99%). 1H-NMR (DMSO-d6) δ 12.91 (s, 1H), 7.99 (d, J=6.0 Hz, 2H), 7.75 (d, J=9.0 Hz, 2H), 5.42 (s, 1H), 5.39 (s, 2H), 1.21 (s, 9H); MS LC-MS [M+H]+=260, RT=1.83 min.

Provenance & Evidence