Reaktionsschritte
H2O2 (70%, 0.46 mL, ca. 9.2 mmol) was added dropwise to a stirred solution of TFAA (1.3 mL, 9.2 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 38 (314 mg, 0.9 mmol) and TFA (0.35 mL, 4.6 mmol) in DCM (20 mL) at 0° C. The solution was stirred at 20° C. for 6 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 1,4-dioxide 39 (118 mg, 36%) as a red solid: mp (MeOH) 170-172° C.; 1H NMR δ 8.12 (s, 1H, H-9), 8.10 (s, 1H, H-5), 7.21 (br s, 1H, NH), 3.56-3.63 (m, 2H, CH2N), 3.12 (br dd, J=7.6, 7.3 Hz, 2H, CH2), 3.07 (br dd, J=7.5, 7.4 Hz, 2H, CH2N), 2.95 (br dd, J=7.5, 7.1 Hz, 2H, CH2N), 2.49-2.57 (m, 2H, CH2N), 2.20 (p, J=7.5 Hz, 2H, CH2), 1.65-1.70 (m, 1H, CH2), 1.53-1.59 (m, 2H, CH2), 1.25-1.40 (m, 3H, CH2), 1.18 (d, J=6.3 Hz, 6H, 2×CH3); 13C NMR δ 155.7, 149.4, 145.7, 137.9, 129.7, 115.8, 111.5, 57.1 (2), 47.2, 39.3, 34.2, 33.4 (2), 32.4, 25.6, 24.4, 21.7 (2). Anal. calcd for C19H27N5O2: C, 63.8; H, 7.6; N, 19.6. Found: C, 64.0; H, 7.6; N, 19.8%.
