4.0 g of (−)-cis-1,2-dimethoxy-4-(2-aminocyclohexyl)benzene (compound C2) are dissolved in 100 ml of methylene chloride and 5.0 ml of triethylamine. The solution is added dropwise at RT to 4.95 g of 3-(4-methoxyphenylcarbamoyl)benzoyl chloride in 50 ml of methylene chloride and the mixture is extracted with 100 ml each of water, 2N hydrochloric acid, satd. sodium hydrogencarbonate solution and water again after stirring overnight. The organic phase is dried using sodium sulfate and concentrated. The residue is taken up in petroleum ether (low)/ethyl acetate in the ratio 2/1, filtered off with suction and dried. 7.14 g of the title compound are obtained.
