反应详情

A mixture of 520 mg of trans-4-(4-pentenyl)cyclohexanecarboxylic acid, 439.4 mg of p-ethoxyphenol, 765.5 mg of dicyclohexylcarbodiimide and 45 mg of 4-(dimethylamino)pyridine were dissolved in 80 ml of methylene chloride and the solution was stirred at room temperature for 20 hours. Subsequently, the reaction mixture was diluted with diethyl ether, the precipitated urea was filtered off and the filtrate was concentrated. The residue was taken up in hexane and the solution was washed with dilute hydrochloric acid, sodium hydrogen carbonate solution and water. The aqueous phases were back-extracted twice with hexane. The organic phases were dried over magnesium sulphate and evaporated. Low-pressure chromatography of the resulting residue on silica gel with ethyl acetate/petroleum ether (vol. 3:97) gave an 0.7 g (83%) of trans-4-(4-pentenyl)cyclohexanecarboxylic acid p-ethoxyphenyl ester. After recrystallization from 3 ml of methanol there were finally obtained 455 mg of product in the form of colourless crystals; m.p. (C-N) 32.7° C., cl.p. (N-I) 57.5° C.

1. filtrationthe precipitated urea was filtered off
2. concentrationthe filtrate was concentrated
3. washthe solution was washed with dilute hydrochloric acid, sodium hydrogen carbonate solution and water
4. extractionThe aqueous phases were back-extracted twice with hexane
5. dry with materialThe organic phases were dried over magnesium sulphate
6. customevaporated