反应详情

To a solution of dimethyl 4-benzyloxy-1H-pyrazole-3,5-dicarboxylate (1.0 g, 3.45 mmol) in anhydrous DMF (20 mL) were added Cs2CO3 (1.35 g, 4.13 mmol) and dibromoethane (2.27 g, 12.1 mmol). The reaction mixture was stirred at room temperature for 2 hours and then filtered. The filtrate was concentrated in vacuo and the residue was purified by flash chromatography on silica gel using a 0-25% EtOAc/hexanes gradient elution. Collection and concentration of the appropriate fractions provided the title compound as a white solid. 1H NMR (400 MHz, d6-DMSO) δ 7.45-7.34 (m, 5H), 5.06 (s, 2H), 4.88 (t, J=6.4 Hz, 2H), 3.86-3.79 (m, 8H).

1. filtrationfiltered
2. concentrationThe filtrate was concentrated in vacuo
3. customthe residue was purified by flash chromatography on silica gel using
4. washa 0-25% EtOAc/hexanes gradient elution
5. customCollection and concentration of the appropriate fractions