To a solution of 5-(3-fluorophenyl)-2,3-dimethyl-benzoic acid (3.82 g, 15.6 mmol, 5.8 eq) in DCM (30 mL) was added (COCl)2 (5.96 g, 46.8 mmol, 17.0 eq) and DMF (0.5 mL). The mixture was stirred at room temperature under N2 for 2 h then the solvent removed in vacuo. The residue obtained was dissolved in THF (10 mL) and added to a mixture of 3-amino-2,4-difluoro-phenol (intermediate X(a)) (0.4 g, 2.75 mmol, 1.0 eq) and Na2CO3 (0.87 g, 8.26 mmol, 3.0 eq) in THF. The reaction was stirred at room temperature overnight then water and EtOAc were added. The organic extract was washed with water, dried (Na2SO4), filtered and evaporated in vacuo. The residue obtained was purified by column chromatography (DCM:MeOH, 0:1 to 1:50) to give the title compound as a solid (0.16 g, 15%).
