反应详情

温度

0 °C

A solution of 5.0 g (0.033 mol) L-alanine ethyl ester hydrochloride is dissolved in 30 ml of dichloromethane. The solution is cooled to 0° C. and 5.42 ml (0.039 mol) of triethylamine is added dropwise over a ten minute period. The mixture is stirred 15 minutes, filtered, concentrated, and diluted with 60 ml of dichloromethane. A mixture of the following is added in a single addition: 4.84 g (0.025 mol) of dicyclohexylcarbodiimide; 200 mg (0.0016 mol) of 4-dimethylaminopyridine; 3.08 g (0.02 mol) of 5-oxo-2-pyrrolidinepropanoic acid. The reaction is allowed to warm to room temperature and stirred for 24 hours. The solids are removed by filtration and are washed with 15 ml of 0° C. dichloromethane. The filtrate is concentrated at reduced pressure to an oil. The oil is chromatographed over silica gel using 19:1 dichloromethane-methanol for elution. Concentration at reduced pressure followed by heating at 0.1 mm pressure and 60° C. yields crystalline analytically pure N-[1-oxo-3-(5-oxo-2-pyrrolidinyl)propyl]-L-alanine, ethyl ester with a melting point of 88°-90° C.

1. filtrationfiltered
2. concentrationconcentrated
3. additiondiluted with 60 ml of dichloromethane
4. additionA mixture of the following
5. additionis added in a single addition
6. temperatureto warm to room temperature
7. stirringstirred for 24 hours
8. customThe solids are removed by filtration
9. washare washed with 15 ml of 0° C. dichloromethane
10. concentrationThe filtrate is concentrated at reduced pressure to an oil
11. customThe oil is chromatographed over silica gel using 19:1 dichloromethane-methanol for elution
12. concentrationConcentration at reduced pressure
13. temperatureby heating at 0.1 mm pressure and 60° C.