反应详情

温度

0 °C

Dimethyl 4-nitro-1H-pyrazole-3,5-dicarboxylate (11.4 g, 50 mmol) was dissolved in tetrahydrofuran (200 mL) and the solution treated with triphenylphosphine (14.4 g, 55 mmol) and 2-isopropoxyethanol (6.36 mL, 55 mmol). The mixture was cooled on an ice bath to 0° C. and diisopropyl azodicarboxylate (10.8 mL, 55 mmol) added dropwise over 10 minutes, keeping the temperature between 20° C. and 30° C. The reaction mixture was then stirred at room temperature for 30 minutes. The reaction mixture was concentrated in vacuo and the crude product azeotroped with dichloromethane to yield the title product. 1H NMR (CDCl3, 400 MHz) δ: 1.02 (d, 6H), 3.45 (m, 1H), 3.72 (t, 2H), 3.90 (s, 3H), 3.94 (s, 3H), 4.74 (t, 2H). MS ES+ m/z 216 [MH]+

1. customthe temperature between 20° C. and 30° C
2. concentrationThe reaction mixture was concentrated in vacuo
3. customthe crude product azeotroped with dichloromethane