反应详情

H2O2 (70%, 0.74 mL, ca. 14.7 mmol) was added dropwise to a stirred solution of TFM (2.1 mL, 14.7 mmol) in DCM (20 mL) at 0° C. The solution was stirred at 0° C. for 5 min, warmed to 20° C. for 10 min, then cooled to 0° C. and added to a stirred solution of 1-oxide 243 (509 mg, 1.5 mmol) and TFA (0.57 mL, 7.4 mmol) in DCM (15 mL) at 0° C. The solution was stirred at 20° C. for 4 h, diluted with dilute aqueous NH3 solution (10 mL) and extracted with CHCl3 (4×50 mL). The combined organic fraction was dried and the solvent evaporated. The residue was purified by chromatography, eluting with a gradient (0-10%) of MeOH/DCM, to give (i) starting material 243 (80 mg, 16%) and (ii) 1,4-dioxide 244 (75 mg, 16%) as a red solid: mp (MeOH/EtOAc) 173-176° C.; 1H NMR δ 8.33 (br t, J=4.9 Hz, 1H, NH), 8.01 (s, 1H, H-5), 7.62 (s, 1H, H-10), 4.31 (br dd, J=5.3, 5.2 Hz, 2H, H-8), 3.83 (br t, J=4.6 Hz, 4H, 2×CH2O), 3.62-3.68 (m, 2H, CH2N), 3.03-3.08 (m, 2H, H-6), 2.58 (br dd, J=6.2, 6.0 Hz, 2H, CH2N), 2.50 (m, 4H, 2×CH2N), 2.07-2.13 (m, 2H, H-7), 1.84-1.91 (m, 2H, CH2); 13C NMR δ 154.5, 148.7, 136.1, 133.2, 129.9, 117.3, 105.2, 67.1, 66.9 (2), 57.8, 53.8 (2), 41.6, 26.1, 24.4, 21.3. Anal. calcd for C17H23N5O3.¼H2O: C, 55.8; H, 6.5; N, 19.1. Found: C, 55.8; H, 6.5, 18.8%.