To a solution of 3-(3-fluorophenyl)-5-methyl-benzoic acid (300 mg, 1.30 mmol, 1.1 eq) (III(q)) in CH2Cl2 (10 mL) was added (COCl)2 (610 mg, 4.81 mmol, 3.3 eq) and DMF (5 drops). The reaction mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure to remove the solvent and excess reagent. The residue obtained was dissolved in THF (10 mL) and added dropwise to a mixture of 3-amino-2,4-dimethylphenol (intermediate X(c)) (163 mg, 1.18 mmol, 1.0 eq) and NaHCO3 (612 mg, 7.30 mmol, 5.0 eq) in THF (20 mL) at 0° C. After addition was completed, the reaction mixture was allowed to warm to room temperature and stirred for 1 h. The resulting mixture was poured into water and extracted with EtOAc. The combined organic extracts were washed with water and brine, dried (Na2SO4), filtered, and evaporated in vacuo. The crude product obtained was purified by column chromatography (CH2Cl2: MeOH, 500:1 to 300:1) to give the title compound as a white solid (290 mg, 57%).
