反应详情

To a solution of 22.0 g (78.5 mmol) of the compound (29) and 65.0 g (471 retool) of potassium carbonate mixed in 300 ml of 2-butanone were added 32.0 g (236 mmol) of butenyl bromide and the whole was refluxed for 18 hours. Water was added to the solution and the whole was extracted with ethyl acetate. After removal of the solvent by distillation, the residue was purified by silica gel column chromatography to obtain 23.6 g of methyl 2-butenyloxy-4-octyloxybenzoate as a colorless clear liquid (yield: 89.9%). Then, 20.0 g (59.8 mmol) of the resulting compound was dissolved in 100 ml of methanol. The solution was poured into a solution of 12.0 g (300 mmol) of sodium hydroxide dissolved in 40 ml of water and 400 ml of methanol. The whole was refluxed for another 2 hours. After removal of the solvent by distillation, the resulting white solid was dissolved in water and the solution was rendered acidic by adding hydrochloric acid, whereby white precipitate formed. The precipitate was extracted with methylene chloride. After removal of the solvent by distillation, the residue was purified by silica gel column chromatography to obtain 15.3 g of 2-butenyloxy-4-octyloxybenzoic acid (30) (yield: 80.0%).

1. temperaturethe whole was refluxed for 18 hours
2. extractionthe whole was extracted with ethyl acetate
3. customAfter removal of the solvent
4. distillationby distillation
5. customthe residue was purified by silica gel column chromatography