反应详情

Ethyl 2-amino-3-ketobutanoate hydrochloride (3.0 g) was added portionwise to a solution of Intermediate 157 (30 g) and triethylamine (26 ml) in ethanol (500 ml) under nitrogen. The resulting solution was left to stand at 22° for 72 h. The solvent was removed in vacuo, then the residue was dissolved in ethyl acetate (200 ml) and washed with water (200 ml). The aqueous layer was further extracted with ethyl acetate (200 ml). The combined organic extracts were dried, concentrated in vacuo and the residue purified by chromatography eluting with System A (8:2) to obtain the title Compound (3.05 g) as a pale yellow solid, m.p. 89°-90° C.

1. waitThe resulting solution was left
2. customThe solvent was removed in vacuo
3. dissolutionthe residue was dissolved in ethyl acetate (200 ml)
4. washwashed with water (200 ml)
5. extractionThe aqueous layer was further extracted with ethyl acetate (200 ml)
6. customThe combined organic extracts were dried
7. concentrationconcentrated in vacuo
8. customthe residue purified by chromatography
9. washeluting with System A (8:2)