反应详情

A solution of dibenzyl N-(N-tert-butoxycarbonyl-L-valyl)-L-glutamate (1 g) and anisole (0.5 ml) in trifluoroacetic acid (2 ml) was stirred at 0° C. for 1 hour. Evaporation of trifluoroacetic acid under reduced pressure gave a residue which was taken up in benzene. Benzene was distilled off by using high vacuum pump. This operation was repeated three times to leave crude dibenzyl N-L-valyl-L-glutamate, which was dissolved in chloroform (20 ml). To this solution were added triethylamine (3 ml) and butyric anhydride (0.5 ml) and the resulting mixture was stirred at room temperature for 4 hours. The reaction mixture was poured into ice water and the separated organic layer was washed with dilute hydrochloric acid solution, a saturated aqueous solution of sodium bicarbonate and brine respectively. After solvent was evaporated, the residue was recrystallized from petroleum ether to afford dibenzyl N-(N-butanoyl-L-valyl)-L-glutamate (613 mg) as crystals.

1. customEvaporation of trifluoroacetic acid under reduced pressure
2. customgave a residue which
3. distillationBenzene was distilled off
4. customto leave crude dibenzyl N-L-valyl-L-glutamate, which
5. washthe separated organic layer was washed with dilute hydrochloric acid solution
6. customAfter solvent was evaporated
7. customthe residue was recrystallized from petroleum ether