Methylamine → N-methyl-1-(4-{5-[3-(trifluoromethyl)-4-(2,2,2-trifluoro-1-methylethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-1H-indol-3-yl)methanamine

To a solution of 4-{5-[3-(trifluoromethyl)-4-(2,2,2-trifluoro-1-methylethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-1H-indole-3-carboaldehyde (150.0 mg) in CH3OH (1.5 ml) was added a 40% CH3OH solution of CH3NH2 (74.5 mg) at 0° C. After warming to room temperature, the solution was stirred at room temperature for 3 hours. After confirming the production of an iminium salt, the organic solvent was evaporated under reduced pressure. The residue was dissolved in EtOH (1.5 ml). To this was added NaBH4 (12.09 mg) at 0° C. After warming to room temperature, the solution was stirred at room temperature for 15 hours. To the reaction solution was added water (30 ml), followed by extraction three times with EtOAc (20 ml). The organic layer was combined, washed with saturated brine, dried over anhydrous MgSO4, and then filtered, and the filtrate was concentrated. The residue was purified by silica gel column chromatography (automatic purifier, chloroform:CH3OH=100:0 to 90:10) to obtain N-methyl-1-(4-{5-[3-(trifluoromethyl)-4-(2,2,2-trifluoro-1-methylethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-1H-indol-3-yl)methanamine (87.4 mg) as a white solid.