[F:1][C:2]([F:18])([F:17])[CH2:3][CH:4]([CH3:16])[C:5]([NH:7][C@H:8]([C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)[CH3:9])=[O:6]>O>[F:1][C:2]([F:17])([F:18])[CH2:3][C@@H:4]([CH3:16])[C:5]([NH:7][C@H:8]([C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)[CH3:9])=[O:6]Impure 4,4,4-trifluoro-2-methyl-N-[(S)-1-phenylethyl]butyramide (94(R):6(S)) (5.0 g), prepared by a method similar to that described in step a) above, was dissolved in industrial methylated spirits (18.75 ml) by heating under reflux with stirring. Water (18.75 ml) was then added slowly, while continuing to heat the solution under reflux. The mixture was then heated under reflux for a further 45 minutes, and was then allowed to cool to room temperature, with continued stirring, overnight. The mixture was then filtered, and the crystalline product was washed with water (10 ml) and dried at 65° C. to give the title compound 4.45 g (89%). The product contained only 0.3% of the unwanted (S)-diastereomer.
Wird geladen…