To the solution of 1 (diclofenac, 890 mg, 3.0 mmol) in 50 mL of N,N-dimethylformamide, hydroxybenzotriazole (445 mg, 3.3 mmol) and DCC (680 mg, 3.3 mmol) were added with stirring at 0° C. for 1 h. To the reaction mixture 4-hydroxybenzamide (4, 616 mg, 4.5 mmol) was added and stirred for 1 h at 0° C. and 3 hs at room temperature. After filtration, the filtrate was evaporated under reduced pressure and the oily residue thus obtained was dissolved in chloroform; the organic layer was washed with brine, dried on anhydrous MgSO4, filtered and the solvent evaporated. The crude product 5 was loaded on a silica gel open column and eluted with CH2Cl2/MeOH (9/1), from which 4-carbamoylphenyl 2-(2-(2,6-dichlorophenylamino)phenyl)acetate (5) was obtained (212 mg, 17% yield).
