To a solution of 950 mg (1.81 mmol) 2-(3,5-bis-trifluoromethyl-phenyl)-N-methyl-N-(2′-methyl-4-nitro-biphenyl-2-yl)-isobutyramide in 12 ml tetrahydrofuran and 3 ml water 608 mg (10.87 mmol) iron powder and 3 drops trifluoroacetic acid were added. After heating at 85° for 3 hrs., the reaction mixture was cooled to room temperature and evaporated. The residue was purified by chromatography (SiO2, hexane/ethyl acetate 1:4) to give 890 mg (99%) N-(4-amino-2′-methyl-biphenyl-2-yl)-2-(3,5-bis-trifluoromethyl-phenyl)-N-methyl-isobutyramide as pale yellow crystals, MS (ISP): 495.2 (M+H)+.
