反应详情

温度

70 °C

To a mixture of 2-(4-(2-amino-5-chloro-3-nitropyridin-4-yl)piperazin-1-yl)-N-(3-methylisoxazol-5-yl)acetamide (0.036 g, 0.09 mmol) and ethanol (4 ml) was added 4-dimethylaminobenzaldehyde (0.018 g, 0.11 mmol) followed by a freshly prepared 1M aqueous solution of Na2S2O4 (0.36 ml, 0.36 mmol). The reaction mixture was stirred at 70° C. for 4.5 h, then allowed to cool to room temperature and concentrated in vacuo. The residue was triturated with water (4 ml); the brown precipitate was collected by filtration, washed with water (3×2 ml), ethanol (3×2 ml) and diethyl ether (2×5 ml). This solid 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 4% methanol in ethyl acetate/dichloromethane (v/v; 1:1). The title compound was obtained as a yellow solid after trituration with diethyl ether (0.007 g, 16%). 1H-NMR (500 MHz, DMSO-d6) 2.19 (s, 3H, isoxazole CH3), 2.73 (s, 4H, piperazine N(CH2)2), 3.00 (s, 6H, N(CH3)2), 3.31 (s, 2H, NCH2CO), 3.71 (s, 4H, piperazine N(CH2)2), 6.18 (s, 1H, isoxazole C—H), 6.82 (d, J=8.9 Hz, 2H) and 8.01 (d, J=8.9 Hz, 2H) (3,5-C6H4NMe2 and 2,6-C6H4NMe2), 8.03 (s, 1H, imidazo[4,5-b]pyridine 5-H), 11.45 (br s, 1H, CONH), 13.15 (br s, 1H, imidazo[4,5-b]pyridine N—H);

1. temperatureto cool to room temperature
2. concentrationconcentrated in vacuo
3. customThe residue was triturated with water (4 ml)
4. filtrationthe brown precipitate was collected by filtration
5. washwashed with water (3×2 ml), ethanol (3×2 ml) and diethyl ether (2×5 ml)
6. customThis solid was absorbed on silica gel
7. washwas eluted with ethyl acetate/dichloromethane (v/v; 1:1), and 4% methanol in ethyl acetate/dichloromethane (v/v; 1:1)