To the solution of 1 (naproxen, 4 g, 17.4 mmol) in 80 mL of dimethylformamide, hydroxybenzotriazole (2.59 g, 19.14 mmol) and DCC (2.59 g, 19.14 mmol) were added with stirring at 0° C. for 1 h. To the reaction mixture 4-hydroxybenzamide (4, 3.58 g, 26.1 mmol) was added and stirred for 1 h at 0° C. and 2 h at room temperature. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, with NaHCO3 5%, with citric acid 10% and than 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 (9.5/0.5), from which 4-carbamoylphenyl 2-(2-methoxynaphthalen-6-yl)-propanoate (5) was obtained (1.91 g, 32% yield).
