10 g (0.057 mol) of 3-(4-cyano-phenyl)propionic acid and 6.6 g (0.065 mol) of N-methyl-morpholine are dissolved in 250 ml tetrahydrofuran and cooled to −20° C. Then 8.2 g (0.06 mol) of isobutyl chloroformate are added dropwise. 13.9 g (0.057 mol) of 6-(trifluoroacetylamino)-1,2,3,4-tetrahydro-quinoline in 200 ml tetrahydrofuran are then added and the solution is left to heat up to ambient temperature overnight. It is then diluted with 200 ml of ethyl acetate and washed with 2×80 ml of 0.5 N hydrochloric acid and then 100 ml of sodium hydrogen carbonate solution. The organic phase is dried over sodium sulphate and concentrated by evaporation in vacuo.
