反应详情

A mixture of 395 mg (1.50 mmol) of ethyl 3-nitro-4-(trifluoromethyl)benzoate (from Step C), 20 mg of platinum oxide, and 6 mL of ethanol was shaken with hydrogen at 3-4 atm. for a few hours, by which time the reaction was essentially complete. The catalyst was removed by filtration, and the filtrate was concentrated to dryness. The residue was chromatographed on silica gel (elution with 25:1 hexane-EtOAc) to afford a 77% yield of the title compound as a pale yellow, gummy foam; TLC in 4:1 hexane-EtOAc; mass spectrum (EI) m/e 233 (M+). 200 MHz 1H NMR (CD3OD) δ1.36 (t, J=7.1 Hz, 3H), 4.33 (q, J=7.1 Hz, 2H), 7.26 (d, J=8 Hz, 1H), 7.44 (d, J=8 Hz, 1H) overlapping 7.47 (s, 1H).

1. customThe catalyst was removed by filtration
2. concentrationthe filtrate was concentrated to dryness
3. customThe residue was chromatographed on silica gel (elution with 25:1 hexane-EtOAc)