反应详情

To a solution of 3-Nitro-1H-pyrazole (1.00 g, 8.84 mmol) in anhydrous N,N-dimethylformamide (20 mL), a 60% dispersion of sodium hydride in mineral oil (390 mg, 9.73 mmol) was added while stirring under nitrogen. After the effervescence ceased and the mixture was stirred for additional 1 h, tert-butyl-bromoacetate (1.44 mL, 9.73 mmol) was added. The mixture was continued to stir under nitrogen for an additional 2 h. The solvent was removed in vacuo and purification by ISCO flash column chromatography (Teledyne Isco RediSep Flash Column 40 g; 0% ethyl acetate/hexanes to 50% ethyl acetate/hexanes, 30 min) afforded (3-nitro-pyrazol-1-yl)-acetic acid tert-butyl ester (1.55 g, 77%) as a white powder. H1-NMR (400 MHz, CDCl3) δ: 1.42 (9H, s), 4.86 (2H, s), 6.87 (1H, d, J=2.4 Hz), 7.54 (1H, d, J=2.3 Hz).

1. stirringthe mixture was stirred for additional 1 h
2. stirringto stir under nitrogen for an additional 2 h
3. customThe solvent was removed in vacuo and purification by ISCO flash column chromatography (Teledyne Isco RediSep Flash Column 40 g; 0% ethyl acetate/hexanes to 50% ethyl acetate/hexanes, 30 min)