反应详情

温度

0 °C

H2O2 (70%, 1.1 mL, ca. 21 mmol) was added dropwise to a stirred solution of TFAA (3.0 mL, 21 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 solution of 1-oxide 64 (0.40 g, 2.1 mmol) in DCM (20 mL) at 0° C. and the solution was stirred at 20° C. for 4 h. Dilute aqueous NH3 solution (10 mL) was added and the mixture stirred vigorously for 30 min and then extracted with DCM (4×50 mL). The combined organic fraction was dried and the solvent evaporated. The residue was purified by chromatography, eluting with a gradient (10-30%) of EtOAc/DCM, to give (i) starting material 64 (68 mg, 17%) and (ii) 1,4-dioxide 65 (213 mg, 49%) as a tan solid: mp (EtOAc/pet. ether) 179-181° C.; 1H NMR δ 8.81 (s, 1H, H-3), 8.31 (s, 1H, H-9), 8.28 (s, 1H, H-5), 3.13-3.22 (m, 4H, H-6, H-8), 2.26 (p, J=7.5 Hz, 2H, H-7); 13C NMR δ 155.2, 152.0, 141.0, 139.1, 134.5, 116.1, 114.1, 33.4, 33.0, 25.5. Anal. calcd for C10H9N3O2: C, 59.1; H, 4.5; N, 20.7. Found: C, 58.9; H, 4.6; N, 20.5%.

1. temperaturewarmed to 20° C. for 10 min
2. temperaturecooled to 0° C.
3. stirringthe solution was stirred at 20° C. for 4 h
4. stirringthe mixture stirred vigorously for 30 min
5. extractionextracted with DCM (4×50 mL)
6. customThe combined organic fraction was dried
7. customthe solvent evaporated
8. customThe residue was purified by chromatography
9. washeluting with a gradient (10-30%) of EtOAc/DCM