反应详情

In 1150 ml of ether was suspended 71 g (146.6 m mol) of D-aspartic acid dibenzyl ester p-toluenesulfonate (41) and while stirring the suspension under ice-cooling (0° C. to 5° C.), 22.5 ml (146.6×1.1 m mol) of triethylamine was added dropwise to the suspension. After stirring the mixture for 2 hours at 0° C. to 5° C., 450 ml of water was added thereto at the same temperature and the mixture was further stirred for 30 minutes. The ether layer thus formed was separated, the aqueous layer was extracted with 200 ml of ether, and the foregoing ether layer was combined with the ether extract. The mixture was washed with 400 ml of a saturated aqueous sodium sulfate solution and dried by anhydrous magnesium sulfate. Ether was distilled off under reduced pressure to provide 45 g of D-aspartic acid dibenzyl ester (42) as a colorless oily product.

1. additionwas added dropwise to the suspension
2. stirringAfter stirring the mixture for 2 hours at 0° C. to 5° C.
3. stirringat the same temperature and the mixture was further stirred for 30 minutes
4. customwas separated
5. extractionthe aqueous layer was extracted with 200 ml of ether
6. extractionextract
7. washThe mixture was washed with 400 ml of a saturated aqueous sodium sulfate solution
8. dry with materialdried by anhydrous magnesium sulfate
9. distillationEther was distilled off under reduced pressure