反应详情

温度

0 °C

The 3-Nitro-1H-pyrazole (prepared in example 3, 1.18 g, 10.44 mmol) was dissolved in anhydrous N,N-dimethylformamide (15 mL) and a 60% dispersion of sodium hydride in mineral oil (500 mg, 12.53 mmol) was added while stirring under nitrogen. After the effervescence ceased and the reaction stirred for an additional 25 min, the reaction was chilled to 0° C. and the 4-bromomethyl-benzoic acid methyl ester (2.63 g, 11.48 mmol) was added. The reaction continued to stir under nitrogen at 0° C. for 20 min. The solution was poured into ice water; a white precipitate formed and was collected by in vacuo filtration and dried in vacuo for 16 h. Recrystallization from 20% ethyl acetate/hexanes afforded 4-(3-nitro-pyrazol-1-ylmethyl)-benzoic acid methyl ester (1.20 g, 44%), as a white powder upon collection and drying in vacuo: H1-NMR (400 MHz, CDCl3) δ 3.93 (3H, s), 5.43 (2H, s), 6.93 (1H, d, J=2.4 Hz), 7.33 (2H, d, J=8.4 Hz), 7.42 (1H, d, J=2.8 Hz), 8.05 (2H, d, J=8.4 Hz).

1. stirringthe reaction stirred for an additional 25 min
2. stirringto stir under nitrogen at 0° C. for 20 min
3. customa white precipitate formed
4. filtrationwas collected by in vacuo filtration
5. customdried in vacuo for 16 h
6. customRecrystallization from 20% ethyl acetate/hexanes