2,5-Difluoroaniline → N-(2,5-difluorophenyl)[[3-(1,1,2,2-tetrafluoroethoxy)phenyl]-methyl]amine

Ex-661A) A mixture of 2,5-difluoroaniline (2.58 g, 20 mmol) and 3-(1,1,2,2-tetrafluoroethoxy)benzaldehyde (4.44 g, 20 mmol) in cyclohexane (50 mL) was heated under reflux for 5 h using a Dean-Stark trap to remove water. The solvent was removed in vacuo, and the residue was dissolved in methanol (30 mL). The solution was stirred and cooled to 0° C., then sodium borohydride was added (1.32 g, 35 mmol). The mixture was allowed to warm to room temperature and stirred for 2 h, then acidified with 1 N HCl. After neutralizing to pH 7.5 with 2.5 N sodium hydroxide, the mixture was extracted with diethyl ether (3×20 mL). The organic layer was washed with brine and water, then dried over anhydrous MgSO4, and evaporated to give 5.7 g (86%) of the desired N-(2,5-difluorophenyl)[[3-(1,1,2,2-tetrafluoroethoxy)phenyl]-methyl]amine product as a brown oil, which was greater than 90% pure by reverse phase HPLC analysis. MS m/z=336 [M+].