反应详情

18.1 g of 4-amino-3-hydroxy-butyric acid are dissolved in 176 ml of 2 N sodium hydroxide. To this there are added within 2 minutes 14.0 g of 3-benzoyloxy-4-methoxybenzoylchloride and subsequently 30 ml of tetrahydrofuran. The mixture is stirred intensively at room temperature for 2 hours, then treated with ice and acidified with concentrated hydrochloric acid. The separated solid is filtered off and washed with water. After drying, the filter cake is boiled in ethyl acetate and the insoluble portion is recrystallised from tetrahydrofuran/n-hexane (3.6:1). There is obtained 4-[(3-benzyloxy-4-methoxybenzoyl)amino]-3-hydroxy-butyric acid of melting point 158°-160° C.

1. additiontreated with ice
2. filtrationThe separated solid is filtered off
3. washwashed with water
4. customAfter drying
5. customthe insoluble portion is recrystallised from tetrahydrofuran/n-hexane (3.6:1)