To a suspension of hydroxylamine hydrochloride (0.24 g, 3.4 mmol) in tetrahydrofuran (5.0 mL) a solution of NaHCO3 (0.40 g, 4.8 mmol) in water (6 mL) was added and the resultant mixture was stirred at ambient temperature for 5 minutes. The reaction mixture was added to a suspension of (E)-3-[4-({4-[3-(trifluoromethyl)phenyl]-1-piperazinyl}sulfonyl)phenyl]-2-propenoyl chloride (10a) (0.31 g) in tetrahydrofuran (5 mL) and the mixture was stirred at ambient temperature for 0.5 hours. The mixture was poured into water (25 mL), the precipitate was filtered, washed with water, ether, and dried to give the title compound (0.23 g, 73%). M.p. 178-179° C. 1H NMR (DMSO-d6, HMDSO), δ: 2.95-3.10 (4H, m); 3.23-3.40 (4H, m, overlapped with a signal of water); 6.62 (1H, d, J=15.9 Hz); 7.09 (1H, d, 3=7.7 Hz); 7.16 (1H, s); 7.19 (1H, d, J=8.0 Hz); 7.40 (1H, t, 3=7.7 Hz); 7.54 (1H, d, J=15.9 Hz); 7.80 (2H, d, J=8.4 Hz); 7.83 (2K, d, J=8.4 Hz); 9.35 (1H, br s); 10.72 (1H, br s). HPLC analysis on Omnispher 5 C18 column: impurities 3.5% (column size 4.6×150 mm; mobile phase acetonitrile−0.1M acetate buffer (pH 5.0), 50:50; sample concentration 1 mg/ml; flow rate 1.3 mL/min; detector UV 254 nm). Anal. Calcd for C20H20F3N3O4S, %: C, 52.74; H, 4.43; N, 9.23; S, 7.04. Found, %: C, 52.04; H, 4.29, N, 8.86; S, 7.20.
