反应详情

To a solution of A-3 (methyl 4-cyano-2-methylbenzoate) (38 g, 0.217 mol) in ethanol (450 mL) was added aqueous sodium hydroxide solution (150 mL, 2.9 M), and the mixture was stirred at room temperature for 12 h. Most of ethanol was removed under reduced pressure, and the residue was diluted with water (300 mL). The aqueous layer was washed with ethyl ether (200 mL×2), and the aqueous layer was acidified with hydrochloric acid (450 mL, 1 M) under 0° C. to pH<6. The mixture was extracted with ethyl acetate (400 mL×3), and the organic layer was washed with brine, dried, and evaporated to give A-4 (4-cyano-2-methylbenzoic acid) (40 g, yield 100%) as a yellow solid.

1. customMost of ethanol was removed under reduced pressure
2. additionthe residue was diluted with water (300 mL)
3. washThe aqueous layer was washed with ethyl ether (200 mL×2)
4. customwas acidified with hydrochloric acid (450 mL, 1 M) under 0° C. to pH<6
5. extractionThe mixture was extracted with ethyl acetate (400 mL×3)
6. washthe organic layer was washed with brine
7. customdried
8. customevaporated