反应详情

A solution of the diethyl 2-(but-3-enyl)-2-(tert-butoxycarbonylamino)malonate (10.0 g, 30.4 mmol) in ethanol (100 mL) was cooled to 0° C. and treated with aqueous sodium hydroxide (1 N, 31 mL). After stirring for 30 minutes, the cooling bath was removed and stirring was continued for an additional 19 h. The solvent was removed by evaporation and the resulting residue was diluted with water (150 mL) and washed with ethyl acetate (2×100 mL). The aqueous layer was acidified with concentrated hydrochloric acid to pH 2 and extracted with ethyl acetate (2×150 mL). The combined organic layers were washed with saturated aqueous sodium chloride (1×100 mL), dried over MgSO4, filtered and concentrated to give 2-(tert-butoxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid (8.2 g, 82%). 1H NMR (CDCl3) δ 5.87-5.75 (m, 1H), 5.06-5.02 (m, 2H), 4.26 (m, 2H), 2.34 (m, 2H), 1.96-1.93 (m, 2H), 1.43 (s, 9H), 1.29 (m, 3H).

1. customthe cooling bath was removed
2. stirringstirring
3. waitwas continued for an additional 19 h
4. customThe solvent was removed by evaporation
5. additionthe resulting residue was diluted with water (150 mL)
6. washwashed with ethyl acetate (2×100 mL)
7. extractionextracted with ethyl acetate (2×150 mL)
8. washThe combined organic layers were washed with saturated aqueous sodium chloride (1×100 mL)
9. dry with materialdried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated