反应详情

温度

0 °C

A solution of (R)-piperidine-3-carboxylic acid (XXVII) (5.0 g, 39 mmol) in a mixture of 50 ml of THF and 20 ml of water was cooled to 0° C. and sodium bicarbonate (6.5 g, 77.4 mmol) and benzyl chloroformate (8.0 g, 46.4 mmol) were added simultaneously. The reaction mixture was stirred at 0° C. for 30 min and at room temperature for 3 hours and concentrated under reduced pressure. The remaining aqueous phase was extracted with ethyl ether to remove excess of benzyl chloroformate, then it was acidified with 1 M HCl solution to pH 6 followed by extraction with ethyl acetate. The organic layer was separated, dried over sodium sulfate and evaporated to provide (R)-piperidine-1,3-dicarboxylic acid 1-benzyl ester (XXVIII) (3.7 g, 36%).

1. concentrationconcentrated under reduced pressure
2. extractionThe remaining aqueous phase was extracted with ethyl ether
3. customto remove excess of benzyl chloroformate
4. extractionfollowed by extraction with ethyl acetate
5. customThe organic layer was separated
6. dry with materialdried over sodium sulfate
7. customevaporated