To a solution of 2-chlorobenzenesulfonic acid 3-[(3-cyanophenyl)methoxy]phenyl ester (280 mg, 0.7 mmol), as prepared in the preceding step, in methylene chloride (10 mL) was added 37% HCl in ethanol (15 mL) at 0° C. The mixture was stirred at room temperature for 2 days. The solvent was evaporated and the residue was co-evaporated with methylene chloride several times. The residue was then dissolved in ethanol (10 mL) and ammonium carbonate (300 mg, 3.0 mmol) was added at 0° C. The mixture was stirred at room temperature overnight. The reaction mixture was diluted with methylene chloride (150 mL), washed with 10% K2CO3 (2×50 mL), and dried over K2CO3. The solvent was removed in vacuo, HCl in methanol (30 mL) was added, and then concentrated in vacuo. The residue was purified by flash chromatography (10% methanol in methylene chloride) to give the title compound as a white foam (238 mg, 75%). 1H-NMR (300 MHz, DMSO-d6) δ 5.15 (s, 2 H), 6.67 (d, 1 H, J=4.0 Hz), 6.81 (s, 1 H), 7.03 (d, 1H, J=4.0 Hz), 7.32 (t, 1 H, J=8.3 Hz), 7.58 (t, 1 H, J=7.5 Hz), 7.65 (t, 1 H, J=7.7 Hz), 7.75-7.94 (m, 6 H), 9.27 (br s, 2 H), and 9.45 (br s, 2 H). Mass spectrum (MALDI-TOF, sinapinic acid matrix) calcd. for C20H17N2ClO4S: 417.1 (M+H), 439.0 (M+Na). Found: 417.4, 439.1.
