Triethylamine → Tert-butyl 2-[(tert-butoxycarbonyl)oxy]-6-[({2'-cyano-4'-[(methoxycarbonyl)methyl]-1,1'-biphenyl-4-yl}oxy)methyl]-3-(trifluoromethyl)benzoate

Participants

Reaction Steps

Triethylamine (71 μl, 0.51 mmol) and methanesulfonyl chloride (23 μl, 0.31 mmol) were added to a solution of crude tert-butyl 2-[(tert-butoxycarbonyl)oxy]-6-[({2′-[(hydroxyimino)methyl]-4′-[(methoxycarbonyl)methyl]-1,1′-biphenyl-4-yl}oxy)methyl]-3-(trifluoromethyl)benzoate (170 mg) obtained in the above in dichloromethane (4 ml), and the mixture was stirred at room temperature for 1 hour. The reaction mixture was diluted with ethyl acetate, successively washed with a saturated aqueous sodium hydrogencarbonate solution, water and a saturated aqueous NaCl solution and dried with anhydrous sodium sulfate. The solvent was removed under reduced pressure. Triethylamine (71 μl, 0.51 mmol) was added to a solution of the obtained residue in ethanol (4 ml) and the mixture was heated under reflux for 14 hours. The solvent was removed under reduced pressure and the obtained residue was subjected to silica gel preparative thin layer chromatography (developing solvent: n-hexane/ethyl acetate=2/1) to give crude tert-butyl 2-[(tert-butoxycarbonyl)oxy]-6-[({2′-cyano-4′-[(methoxycarbonyl)methyl]-1,1′-biphenyl-4-yl}oxy)methyl]-3-(trifluoromethyl)benzoate (125 mg).

Provenance & Evidence