反应详情

To a suspension of lithium bromide (18.06 g, 207.99 mmol) in acetonitrile (80 mL) and water (1.6 mL) was added triethylamine (14.42 mL, 104.00 mmol) followed by dimethyl 2-(2,4-difluorobenzyl)piperidine-1,4-dicarboxylate (8.51 g, 26.00 mmol) in acetonitrile (40 mL). The resulting mixture was heated under reflux for 2 h 30 min, then cooled to room temperature and water and MTBE were added. The organic phase was extracted with water twice. The pooled aqueous layers were adjusted to pH 1 with 3.8 M HCl and then extracted with DCM (3×). The combined organic layers were dried over MgSO4 and evaporated to yield 2-(2,4-difluorobenzyl)-1-(methoxycarbonyl)piperidine-4-carboxylic acid (7.48 g, 92%) as an orange solid. MS m/z 314 (M+H)+

1. temperatureThe resulting mixture was heated
2. temperatureunder reflux for 2 h 30 min
3. extractionThe organic phase was extracted with water twice
4. extractionextracted with DCM (3×)
5. dry with materialThe combined organic layers were dried over MgSO4
6. customevaporated