反应详情

H2O2 (70%, 0.60 mL, ca. 11.9 mmol) was added dropwise to a stirred solution of TFAA (1.7 mL, 11.9 mmol) in DCM (15 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 60 (412 mg, 1.2 mmol) and TFA (0.46 mL, 6.0 mmol) in DCM (20 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 60 (208 mg, 50%) and (ii) 1,4-dioxide 61 (122 mg, 30%) as a red solid: mp (MeOH) 158-160° C.; 1H NMR δ 8.37 (br s, 1H, NH), 8.11 (s, 1H, H-5), 8.09 (s, 1H, H-9), 3.80-3.84 (m, 4H, 2×CH2O), 3.64-3.69 (m, 2H, CH2N), 3.02-3.10 (m, 4H, H-6, H-8), 2.56 (dd, J=6.2, 6.1 Hz, 2H, CH2N), 2.48-2.52 (m, 4H, 2×CH2N), 2.15-2.22 (m, 2H, H-7), 1.85-1.91 (m, 2H, CH2); 13C NMR δ 155.5, 149.5, 145.6, 138.0, 129.6, 115.8, 111.6, 66.9 (2), 57.7, 53.8 (2), 41.6, 33.3, 32.3, 25.5, 24.5. Anal. calcd for C17H23N5O3.¼CH3OH: C, 58.6; H, 6.9; N, 19.8. Found: C, 58.4; H, 6.7; N, 19.9%.