反应详情

Heat a suspension of methyl 5-bromo-2-isopropoxycarbonylaminobenzoate (10.0 g, 31.6 mmol), methyl 4-bromobutyrate (22.9 g, 126 mmol) and cesium carbonate (41.6 g, 126 mmol) in N,N-dimethylformamide (150 mL) under nitrogen at 80° C. for 24 h. Cool the mixture to room temperature and pour into water (200 mL). Extract with ethyl acetate (3×100 mL) and wash the organic extracts with water (3×100 mL) and brine (100 mL). Dry the organic layer over anhydrous sodium sulfate, filter, and remove the solvent under reduced pressure. Chromatograph the residue over silica gel, eluting with hexanes/ethyl acetate (60:40), to provide the title compound as a colorless oil (11.8 g, 89%). 1H NMR (CDCl3, 300 MHz) δ 1.05-1.07 (m, 4H), 1.30-1.32 (m, 2H), 1.89-1.94 (m, 2H), 2.38-2.44 (m, 2H), 3.46-3.60 (m, 1H), 3.65 (s, 3H), 3.68-3.79 (m, 1H), 3.86 (s, 3H), 4.85-5.01 (m, 1H), 7.12 (d, J=8.3 Hz, 1H), 7.62 (dd, J=1.7, 8.4 Hz, 1H), 8.07 (brs, 1H); ESI MS m/z 416 [C17H22BrNO6+H]+.

1. temperatureHeat
2. extractionExtract with ethyl acetate (3×100 mL)
3. washwash the organic extracts with water (3×100 mL) and brine (100 mL)
4. dry with materialDry the organic layer over anhydrous sodium sulfate
5. filtrationfilter
6. customremove the solvent under reduced pressure
7. washChromatograph the residue over silica gel, eluting with hexanes/ethyl acetate (60:40)