A solution of 3-(3-chlorosulfonylphenyl)acrylic acid methyl ester (3) (1.0 g, 3.83 mmol) in dioxane (10 ml) was added to a mixture of 2-aminonaphthalene (0.55 g, 3.83 mmol) and NaHCO3 (0.48 g, 5.71 mmol) in water (6 ml), and the resultant solution was stirred at room temperature until the completion of the reaction (control by TLC). The reaction mixture was evaporated and the residue was partitioned between ethyl acetate and 2N HCl. The organic layer was washed successively with water, saturated NaCl, and dried (Na2SO4). The solvent was removed and the residue was chromatographed on silica gel with petroleum ether-ethyl acetate (3:2, v/v) as eluent. The obtained product was crystallised from petroleum ether-ethyl acetate to give the title compound (0.52 g, 34%) as a white solid. 1H NMR (DMSO-d6, HMDSO), δ: 3.73 (3H, s); 6.67 (1H, d, J=16.0 Hz); 7.21-8.07 (11H, m); 8.16 (1H, s); 10.55 (1H, s).
