To a solution of 5-(3-fluorophenyl)-2,3-dimethyl-benzoic acid (intermediate III(m)) (500 mg, 2.0 mmol, 1.0 eq) in CH2Cl2 (10 mL) at 0° C. was added oxalyl chloride (770 mg, 6.1 mmol, 3.0 eq) and DMF (0.1 mL) and the reaction was stirred for 1 h. The solvent and excess reagent were removed under reduced pressure and the residue obtained was dissolved in THF (10 mL) and added to a mixture of 3-amino-4-fluoro-2-methyl-phenol (intermediate X(e)) (280 mg, 2.0 mmol, 1.0 eq) and Na2CO3 (860 mg, 8.1 mmol, 4.0 eq) in THF (10 mL) at 0° C. The reaction was stirred for 3 h, then filtered and concentrated in vacuo. The residue obtained was purified by column chromatography (petroleum ether:EtOAc, 400:1 to 4:3) to give the title compound as a brown solid (300 mg, 40%).
