反应详情

温度

70 °C

To a mixture of 5-bromo-3-nitro-4-(4-(pyridin-2-ylmethyl)piperazin-1-yl)pyridin-2-amine (0.043 g, 0.11 mmol), and ethanol (2.5 ml) was added 4-methoxybenzaldehyde (0.024 g, 0.18 mmol) with the aid of ethanol (1 ml) followed by a freshly prepared aqueous solution of Na2S2O4 (1M; 0.44 ml, 0.44 mmol). The reaction mixture was heated at 70° C. for 4 h, then allowed to cool to room temperature and the solvents were removed in vacuo. The residue was absorbed on silica gel and the free running powder was placed on a 10 g isolute silica column which was eluted with ethyl acetate/dichloromethane (v/v; 1:1), and then 4% methanol in ethyl acetate/dichloromethane (v/v; 1:1). The title compound was obtained as a yellow solid after trituration with diethyl ether (0.010 g, 19%); 1H-NMR (500 MHz, DMSO-d6) 2.67 (br s, 4H, piperazine N(CH2)2), 3.68 (br s, 4H, piperazine N(CH2)2), 3.70 (s, 2H, NCH2), 3.84 (s, 3H, OMe), 7.10 (d, J=8.86 Hz, 2H) and 8.13 (d, J=8.75 Hz, 2H) (3,5-C6H4OMe and 2,6-C6H4—OMe), 7.28 (dd, J=5.00, 6.45 Hz, 1H), 7.52 (d, J=7.80 Hz, 1H), 7.79 (td, J=1.75, 7.65 Hz, 1H) and 8.52 (d, J=4.80 Hz, 1H) (pyrid-2-yl protons), 8.20 (s, 1H, imidazo[4,5-b]pyridine 5-H), 13.35 (s, 1H, imidazo[4,5-b]pyridine N—H);

1. temperatureto cool to room temperature
2. customthe solvents were removed in vacuo
3. customThe residue was absorbed on silica gel
4. washwas eluted with ethyl acetate/dichloromethane (v/v; 1:1)