2.1.24. N-benzyl-N-(4-bromo-3,5-dimethoxyphenyl)-4-methoxybenzenesulfonamide (326A), N-benzyl-N-(2-bromo-3,5-dimethoxyphenyl)-4-methoxybenzenesulfonamide (326B) and N-benzyl-N-(2,4-dibromo-3,5-dimethoxyphenyl)-4-methoxybenzenesulfonamide (326C)

To a solution of 270 (195 mg, 0.47 mmol) in CH₂Cl₂ (40 mL) N-bromosuccinimide (168 mg, 0.94 mmol) was added and stirred for 48 h at room temperature. After that, the reaction was washed with water, dried over anhydrous Na₂SO₄ and the solvent evaporated in vacuum to produce 183 mg. The residue was flash chromatographed on silica gel (hexane/EtOAc 8:2) to afford the purified compounds: 326A (116 mg, 50%), 326B (24 mg, 10%) and 326C (6 mg, 2%). 326A: M.p.: 199–203 °C (MeOH). IR (KBr): 3435, 1589, 836 cm⁻¹. ¹H NMR (200 MHz, CDCl₃): δ 3.65 (6H, s), 3.88 (3H, s), 4.68 (2H, s), 6.12 (2H, s), 6.97 (2H, d, J = 9), 7.22 (5H, bs), 7.65 (2H, d, J = 9). ¹³C NMR (100 MHz, CDCl₃): δ 54.9 (CH₂), 55.7 (CH₃), 56.4 (2CH₃), 100.5 (C), 105.8 (2CH), 114.0 (2CH), 127.8 (CH), 128.4 (2CH), 128.6 (2CH), 129.9 (C), 130.0 (2CH), 135.7 (C), 139.4 (C), 156.7 (2C), 163.1 (C). HRMS (C₂₂H₂₂BrNO₅S + H⁺): calcd 492.0475 and 494.0454 (M + H⁺), found 492.0473 and 494.0440. 326B: IR (KBr): 2938, 1593, 831 cm⁻¹. ¹H NMR (200 MHz, CDCl₃): δ 3.57 (3H, s), 3.80 (3H, s), 3.87 (3H, s), 4.60 (1H, d, J = 14.4), 4.89 (1H, d, J = 14.4), 6.14 (1H, d, J = 2.8), 6.38 (1H, d, J = 2.8), 6.94 (2H, d, J = 9), 7.20 (5H, bs), 7.74 (2H, d, J = 9). ¹³C NMR (100 MHz, CDCl₃): δ 54.4 (CH₂), 55.5 (CH₃), 55.6 (CH₃), 56.3 (CH₃), 100.0 (CH), 105.9 (C), 109.4 (CH), 113.9 (2CH), 127.7 (CH), 128.2 (2CH), 129.4 (2CH), 130.1 (2CH), 131.8 (C), 135.7 (C), 138.8 (C), 157.2 (C), 158.9 (C), 163.0 (C). HRMS (C₂₂H₂₂BrNO₅S + H⁺): calcd 492.0475 and 494.0454 (M + H⁺), found 492.0467 and 494.0447. 326C: IR (KBr): 2935, 1595, 835 cm⁻¹. ¹H NMR (200 MHz, CDCl₃): δ 3.60 (3H, s), 3.77 (3H, s), 3.87 (3H, s), 4.55 (1H, d, J = 14.4), 4.97 (1H, d, J = 14.4), 6.30 (1H, s), 6.95 (2H, d, J = 9), 7.22 (5H, m), 7.73 (2H, d, J = 9). ¹³C NMR (100 MHz, CDCl₃): δ 54.2 (CH₂), 55.6 (CH₃), 56.5 (CH₃), 60.5 (CH₃), 108.8 (C), 112.4 (C), 112.8 (CH), 114.0 (2CH), 128.0 (CH), 128.3 (2CH), 129.4 (2CH), 130.0 (2CH), 131.5 (C), 135.4 (C), 137.4 (C), 155.6 (C), 155.7 (C), 163.2 (C). HRMS (C₂₂H₂₁Br₂NO₅S + H): calcd 569.9580 and 571.9559 (M⁺ + H), found 569.9577 and 571.9558.