反应详情

温度

0 °C

A solution of 5.0 g (0.03 mol) L-proline methyl ester hydrochloride is dissolved in 30 ml of dichloromethane. The solution is cooled to 0° C. and 4.42 ml (0.032 mol) triethylamine is added dropwise over a ten minute period. The mixture is stirred 15 minutes and a mixture of the following is added in a single addition: 6.85 g (0.033 mol) of dicyclohexylcarbodiimide; 200 mg (0.0016 mol) of 4-dimethylaminopyridine; 4.71 g (0.03 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 12:1 dichloromethanemethanol for elution. Concentration at reduced pressure followed by heating at 0.1 mm pressure and 60° C. yields 1-[1-oxo-3-(5-oxo-2-pyrrolidinyl)propyl]-L-proline, methyl ester as an analytically pure oil (0.55 hydrate) with the following characteristic proton NMR spectrum: 1H-NMR (CDCL3) 1.6-2.5 (m, 14H), 3.4-3.85 (m, 2H), 3. (s, 3H), 4.5 (m, 1H), 6.37 (m, 1H).

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