反应详情

Acetic anhydride (1.0 mL. 10.8 mmol) and triethylamine (2.4 g. 24 mmol) were added sequentially to a solution of rac.-2-amino-3-[4-[(1.1-dimethylethoxy)carbonyl]phenyl]propanoic acid benzyl ester p-toluenesulfonic acid salt (5.0 g, 9 mmol) in dichloromethane (100 ml) at 0° C. After 2 h. the reaction mixture was diluted with dichloromethane (250 mL) and washed with 1N HCI (2×20 mL), saturated aqueous sodium bicarbonate (2×20 mL) and dried (Na2SO4 ). Filtration and concentration provided the crude product which was purified by HPLC on silica gel eluting with a mixture of hexanes and ethyl acetate to give rac.-2-acetamido-3-[4-[(1,1-dimethylethoxy)carbonyl]phenyl]propanoic acid benzyl ester (3.3 g. 8 mmol) in 91% yield.

1. washwashed with 1N HCI (2×20 mL), saturated aqueous sodium bicarbonate (2×20 mL)
2. dry with materialdried (Na2SO4 )
3. filtrationFiltration and concentration
4. customprovided the crude product which
5. customwas purified by HPLC on silica gel eluting with a mixture of hexanes and ethyl acetate