反应详情

To the cold (5°) solution of 1.2 g. (10 mMol.) of 3-mercapto-2-methylpropanoic acid and 1.7 g. (10 mMol.) of L-proline tert.butyl ester in 25 ml. dichloromethane 2.26 g. of dicyclohexylcarbodiimide in 5 ml. dichloromethane is added in portions. After 2 hours at room temperature, 5 drops of acetic acid are added, the mixture is filtered and the filtrate evaporated to an oily residue. This residue is taken up in 20 ml. of petroleum ether-ethyl acetate (3:1) and applied to a 150 ml. silica gel column prepared in petroleum ether. The fraction eluted with petroleum ether-ethyl acetate (1:1) contains the product, 1-(3-Mercapto-2-methylpropanoyl)-L-proline tert.butyl ester. This fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours. Rf 0.6 (Silica gel, Benzene/Acetic acid 3:1), Rf 0.8 (Silica gel, Methyl-ethylketone/acetic acid/pyridine/water 14:1:2:1).

1. customTo the cold (5°) solution of 1.2 g
2. filtrationthe mixture is filtered
3. customthe filtrate evaporated to an oily residue
4. customsilica gel column prepared in petroleum ether
5. washThe fraction eluted with petroleum ether-ethyl acetate (1:1)
6. dry with materialThis fraction (0.6 g.) is dried over P2O5 in vacuo for 12 hours