反应详情

4-(2-Pyrrolidon-1-yl)benzoic acid (4.0 g, 0.0195 mol), 5% rhodium-carbon catalyst (6.89 g, 1.5% mol) and methanol (200 mL) are charged in an autoclave (300 mL) and stirred at room temperature for 24 hours under hydrogen pressure (9 atm, conversion rate>99%, cis:trans=75:25). The reaction solution is concentrated to 100 ml, adjusted to pH 2 with conc. hydrochloric acid (11 g), and extracted with chloroform (100 mL) (×3). The organic layers are combined, washed with saturated brine (100 mL), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The resulting crystals are collected with toluene, and air-dried at 50° C. overnight to give 4-(2-pyrrolidon-1-yl)cyclohexylcarboxylic acid (19.3 g, 93.7%, cis:trans=65:35).

1. concentrationThe reaction solution is concentrated to 100 ml
2. extractionextracted with chloroform (100 mL) (×3)
3. washwashed with saturated brine (100 mL)
4. dry with materialdried over anhydrous magnesium sulfate
5. concentrationconcentrated under reduced pressure
6. customThe resulting crystals are collected with toluene
7. customair-dried at 50° C. overnight