反应详情

In a procedure analogous to Example B6, isopropylhydrazine hydrochloride (896 mg, 8.10 mmol) and ethyl 2-acetyl-3-(dimethylaminomethylene)acrylate (1.50 g, 8.10 mmol) were combined and purified by chromatography (ethyl acetate/hexane) to afford ethyl 1-isopropyl-5-methyl-1H-pyrazole-4-carboxylate (faster elution, 537 mg), 1H NMR (300 MHz, DMSO-d6): δ 1.30 (t, 3 H), 1.39 (d, 6 H), 4.23 (q, 2 H), 4.61 (hp, 1 H), 7.82 (s, 1 H); MS (ESI) m/z: 197.0 (M+H+) and ethyl 1-isopropyl-3-methyl-1H-pyrazole-4-carboxylate (slower elution, 91 mg), 1H NMR (300 MHz, DMSO-d6), δ 1.29 (t, 3 H), 1.42 (d, 6 H), 2.36 (s, 3 H), 4.21 (q, 2 H), 4.49 (hp, 1 H), 8.24 (s, 1 H); MS (ESI) m/z: 197.0 (M+H+).

1. custompurified by chromatography (ethyl acetate/hexane)