反应详情

Into a 500 ml flask was placed 3.0 g of 3-(2-Thienyl)-D,L-alanine (optically active material in the L-form is available from Aldrich or SIGMA and could be used to obtain an optically active product) in 75 ml H2O/60 ml dioxane, and 5.6 g K2CO3 was added, followed by 2.85 ml of carbobenzyloxy chloride. The mixture was stirred rapidly for 1 hour. TLC (21/7/7/9, EtOAc/AcOH/CH3CN/H2O) showed that the starting material was gone. A new higher Rf product was seen. The dioxane was concentrated off and the aqueous layer was-washed with Et2O (75 ml). The aqueous layer was mixed with CH2Cl2 (150 ml) and acidified to pH=2.0 with 5N HCl. The desired N-(Benzyloxycarbonyl)-3-(2-thienyl)-D,L-alanine was extracted with CH2Cl2. The organic layer was separated and dried with Na2So4, filtered, and concentrated to give 5.05 g of desired N-(Benzyloxycarbonyl)-3-(2-thienyl)-D,L-alanine (98% yield).

1. customInto a 500 ml flask was placed
2. concentrationThe dioxane was concentrated off
3. washthe aqueous layer was-washed with Et2O (75 ml)
4. additionThe aqueous layer was mixed with CH2Cl2 (150 ml)
5. extractionThe desired N-(Benzyloxycarbonyl)-3-(2-thienyl)-D,L-alanine was extracted with CH2Cl2
6. customThe organic layer was separated
7. customdried with Na2So4
8. filtrationfiltered
9. concentrationconcentrated