2-Bromo-3′-chloro-4′-fluoroacetophenone (available from Aldrich Chemical Company, Inc.; 80.5 mg, 0.32 mmol) was added to a solution of 2′-nitro-4-thiocarbamoyl-biphenyl-2-carboxylic acid methyl ester (which may be prepared as described for Intermediate 4; 100 mg, 0.32 mmol) in THF (2 mL), and the resulting mixture was stirred at 40° C. for 20 h. The reaction mixture was evaporated to dryness and the residue was stirred with ethanol (5 mL). The precipitate was collected by filtration (100 mg) and used directly in the next step without purification.
