反应详情

温度

0 °C

Dimethyl 4-nitro-1H-pyrazole-3,5-dicarboxylate (WO00/24745, page 48, preparation 2) (15 g, 60 mmol), 2-propoxyethanol (8.2 mL, 70 mmol) and triphenylphosphine (18.9 g, 70 mmol) were dissolved in tetrahydrofuran (150 mL) and the solution cooled to 0° C. The solution was treated with diisopropyl azodicarboxylate (14.2 mL, 70 mmol) and the reaction mixture stirred at 0° C. for 3 hours before being allowed to warm to room temperature. The reaction mixture was concentrated in vacuo and the residue purified by column chromatography on silica gel eluting with ethyl acetate:pentane 15:85 and then again eluting with dichloromethane to yield the title product. 1H NMR (CD3OD, 400 MHz) δ: 0.82 (t, 3H), 1.47 (q, 2H), 3.34 (t, 2H), 3.78 (t, 2H), 3.91 (s, 6H), 4.76 (t, 2H). MS APCI+ m/Z 316 [MH]+

1. temperatureto warm to room temperature
2. concentrationThe reaction mixture was concentrated in vacuo
3. customthe residue purified by column chromatography on silica gel eluting with ethyl acetate:pentane 15:85
4. washagain eluting with dichloromethane