反应详情

To a mixture 2-[4-(2-amino-5-bromo-3-nitro-pyridin-4-yl)-piperazin-1-yl]-N-thiazol-2-yl-acetamide (0.100 g, 0.22 mmol) and ethanol (3 ml) was added 4-dimethylamino benzaldehyde (0.044 g, 0.29 mmol) and 1M aq. Na2S2O4 (900 μL, 0.9 mmol). The reaction mixture was stirred at reflux for 16 h then concentrated in vacuo. The crude product was purified by chromatography on silica gel (dichloromethane/ethyl acetate v/v 7:3, and then 0.5% to 2% methanol in ethyl acetate) to give the title compound as an off white solid (0.034 g, 27%); 1H-NMR (250 MHz, DMSO-d6) 2.77 (broad m, 4H, piperazine N(CH2)2), 2.99 (s, 6H, N(CH3)2), 3.40 (s, 2H, NCH2CO), 3.67 (broad m, 4H, piperazine N(CH2)2), 6.82 (d, J=8.8 Hz, 2H) and 8.02 (d, J=8.8 Hz, 2H) 2,6-ArH and 3,5-ArH, 7.23 (d, J=3.5 Hz, 1H) and 7.49 (d, 1H, J=3.5 Hz) (thiazole 4-H, 5-H), 8.15 (s, 1H, imidazo[4,5-b]pyridine 5-H), 11.80 (broad s, 1H, CONH), 13.12 (broad s, 1H, imidazo[4,5-b]pyridine NH); LC-MS (ESI, m/z) Rt=6.0 min—541/543 [(M+H+), Br isotopic pattern, 100%]; ESI-HRMS Found: 541.1203, calculated for C23H26N8OSBr (M+H+): 541.1134.

1. temperatureat reflux for 16 h
2. concentrationthen concentrated in vacuo
3. customThe crude product was purified by chromatography on silica gel (dichloromethane/ethyl acetate v/v 7:3