反应详情

A mixture of 26 g (117.5 mmol) of (S)-1-(4-hydroxy-phenyl)-5-oxo-pyrrolidine-3-carboxylic acid, 0.66 ml of sulfuric acid, and 100 ml of dimethoxypropane in 700 ml of methanol are heated to reflux for 3 hours. For the working-up, the reaction mixture is reduced to ⅘ of its volume, then the residue is added under stirring to a mixture of ice and water. The precipitated product is collected on a filter funnel, washed with cold water and finally dried under high vacuum to yield 23.7 g (86% of theory) of (S)-1-(4-hydroxy-phenyl)-5-oxo-pyrrolidine-3-carboxylic acid methyl ester as a white solid; MS: m/e=234 (M−H)+; optical integrity: 97.4% e.e. .

1. temperatureare heated
2. temperatureto reflux for 3 hours
3. additionthe residue is added
4. customThe precipitated product is collected on a filter funnel
5. washwashed with cold water
6. customfinally dried under high vacuum