反应详情

To a solution of 13.0 g (0.04 mol) of (R) (+)-2-[4-(5-chloro-3-fluoropyridin-2-yloxy)]-methyl ester in 65 ml of dioxane are added 42 ml of 1N sodium hydroxide and the mixture is stirred for 21/2 hours at a temperature of 35°. Then it is poured onto an ice/water mixture and acidified with 22 ml of 2N hydrochloric acid. The organic material is extracted therefrom twice with ethyl acetate. The organic layers are washed with a saturated salt solution and dried over magnesium sulfate, filtered and concentrated. The residue is cristallized from ethyl acetate/hexane and yields 10.2 g (81.8% of the theory) of the above (2R) (+)-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phenoxy]-propionic acid as white cristals, which melt at 95°-96° ([α]D20 =+37.5°±0.5°2% in acetone).

1. extractionThe organic material is extracted
2. washThe organic layers are washed with a saturated salt solution
3. dry with materialdried over magnesium sulfate
4. filtrationfiltered
5. concentrationconcentrated