Methyl chlorodifluoroacetate → 5-n-Butyl-4-[[2'-(N-t-butylsulfamoyl)biphenyl-4-yl]methyl]-2,4-dihydro-2-[5-nitro-2-(trifluoromethyl)phenyl]-3H-1,2,4-triazol-3-one

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To a solution of 600 mg (0.935 mmol) of 2-(2-bromo-5-nitrophenyl)-4-[[2'-(N-t-butylsulfamoyl)biphenyl-4-yl]methyl]-5-n-butyl-2,4-dihydro-3H-1,2,4-triazol-3-one (from Step B) in 1.87 mL of DMF were added 65 mg (1.12 mmol) of potassium fluoride, 179 mg (0.935 mmol) of cuprous iodide, and 197 μL (270 mg, 1.87 mmol) of methyl chlorodifluoroacetate. The mixture was stirred in a sealed tube at 120° C. for 12 hours. The cooled mixture was diluted with H2O and extracted 3× with ethyl acetate. The combined organic extracts were washed with H2O, then brine, and dried over Na2SO4. The residue obtained upon evaporation of the filtered solution was flash chromatographed on silica gel (gradient elution with 8.5:1 to 5:1 hexane-EtOAc) to give 216 mg (37%) of the title compound as a solid, mp 135°-137° C. [Subsequently eluted was 187 mg (32%) of the corresponding 2-chloro-5-nitrophenyl analog, obtained as a byproduct.] The desired product was homogeneous by TLC (98:2 CH2Cl2 --MeOH); mass spectrum (FAB) m/e 638 (M+Li)+ .

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