To a suspension of hydroxylamine hydrochloride (0.2 g, 2.85 mmol) in tetrahydrofuran (3.5 ml) a saturated NaHCO3 solution (2.3 ml) was added and the resultant mixture was stirred at ambient temperature for 10 min. To the reaction mixture a solution of crude 3-[3-(naphthalen-2-ylsulfamoyl)-phenyl]-acryloyl chloride (16e) (0.21 g) in tetrahydrofuran (2.5 ml) was added and the mixture was stirred at ambient temperature for one hour. The reaction mixture was partitioned between ethyl acetate and 2N HCl. The organic layer was washed successively with water and saturated NaCl, then the solvent was removed. The residue was washed with diethyl ether and petroleum ether-ethyl acetate (3:1) affording the title compound (0.14 g, 68%). M.p. 164° C. 1H NMR (DMSO-d6, HMDSO) δ: 6.49 (1H, d, J=16.0 Hz); 7.16-7.89 (12H, m); 7.98 (1H, br s); 10.52 (1H, s); 10.76 (1H, br s). HPLC analysis on Symmetry C18 column: impurities 5% (column size 3.9×150 mm; mobile phase acetonitrile—0.1M phosphate buffer (pH 2.5), 50:50; sample concentration 0.5 mg/ml; flow rate 0.8 ml/min; detector UV 220 nm). Anal. Calcd for C19H16N2O4S, %: C 61.94, H 4.38, N 7.60. Found, %: C 61.44, H 4.39, N 7.48.
