反应详情

Methyl 2,4-bis-benzyloxy-5-isopropenyl-benzoate (700 mg, 1.80 mmol) was dissolved in methanol (20 ml), a solution of potassium hydroxide (286 mg, 5.1 mmol) in water (4 ml) was added and the mixture was stirred and held at reflux for 3 hours. Upon cooling the solvent was removed in vacuo and the mixture acidified to pH 2 or below by the addition of 2M hydrochloric acid. The mixture was extracted with dichloromethane, the organic layer was separated and the solvent removed in vacuo to afford 2,4-bis-benzyloxy-5-isopropenyl-benzoic acid (600 mg, 89%) as a colourless solid. 1H NMR (DMSO-d6) 7.52 (2H, d), 7.47-7.29 (9H, m), 6.82 (1H, s), 5.20 (2H, s), 5.17 (2H, s), 5.06 (1H, s), 5.04 (1H, s), 2.03 (3H, s). MS: [M+H]+ 375.

1. temperatureat reflux for 3 hours
2. temperatureUpon cooling the solvent
3. customwas removed in vacuo
4. additionthe mixture acidified to pH 2 or below by the addition of 2M hydrochloric acid
5. extractionThe mixture was extracted with dichloromethane
6. customthe organic layer was separated
7. customthe solvent removed in vacuo