反应详情

H2O2 (70%, 0.65 mL, ca. 12.9 mmol) was added dropwise to a stirred solution of TFAA (1.8 mL, 12.9 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 96 (371 mg, 1.3 mmol) and TFA (0.50 mL, 6.5 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 (4×30 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 96 (181 mg, 49%) and (ii) 1,4-dioxide 97 (103 mg, 26%) as a red solid: mp (MeOH/DCM) 149-151° C.; 1H NMR δ 8.09 (s, 1H, H-9), 8.07 (s, 1H, H-5), 7.52 (br s, 1H, NH), 3.58-3.64 (m, 2H, CH2N), 3.14-3.27 (m, 2H, CH2), 2.63-2.75 (m, 3H, CH, CH2), 2.59 (br t, J=6.0 Hz, 2H, CH2), 2.28 [s, 6H, N(CH3)2], 1.18 (d, J=6.2 Hz, 3H, CH3); 13C NMR δ 155.6, 149.4, 145.5, 138.0, 128.9, 115.8, 111.8, 57.4, 45.0 (2), 41.4, 40.4, 38.7, 34.8, 20.1. Anal. calcd for C15H21N5O2.½CH2Cl2: C, 54.6; H, 6.3; N, 19.9. Found: C, 54.4; H, 6.0; N, 19.8%.