反应详情

A mixture of 0.47 mol of ethyl 4-trifluoromethylbenzoate (prepared from 4-trifluoromethylbenzoyl chloride, ethanol and pyridine), 1000 ml of ethanol and 20 g of rhodium/activated charcoal (5%) is hydrogenated for 5 hours under a pressure of 5 bar and at a temperature of 60° C. The ethyl 4-trifluoromethylcyclohexanecarboxylate (cis/trans =87%/13%) obtained after removal of the catalyst by filtration and removal of the solvent is, without prior purification, suspended in 300 ml of water and treated with 70 g of 30% sodium hydroxide solution, and the mixture is briefly heated to boiling and stirred at room temperature for 18 hours. Acidification using hydrochloric acid gives the carboxylic acid as a cis/trans mixture.