反应详情

To a solution of 3-nitro-1H-pyrazole (prepared in example 3, 2.00 g, 17.70 mmol) in anhydrous N,N-dimethylformamide (30 mL), a 60% dispersion of sodium hydride in mineral oil (778 mg, 19.50 mmol) was added while stirring under nitrogen. After the effervescence ceased and the mixture was stirred for additional 30 min, 3-bromo-propionic acid tert-butyl ester (3.25 mL, 19.50 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; 2% methanol/methylene chloride to 5% methanol/methylene chloride) to afford (3-nitro-pyrazol-1-yl)-propionic acid tert-butyl ester (2.30 g, 57%) as a yellow oil.

1. stirringthe mixture was stirred for additional 30 min
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; 2% methanol/methylene chloride to 5% methanol/methylene chloride)