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 (3 ml) was added p-anisaldehyde (0.024 g, 0.18 mmol) with the aid of ethanol (1 ml) 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 6.5 h, then allowed to cool to room temperature and concentrated in vacuo. The residue was absorbed on silica gel, and the free-running powder was placed on a 10 g silica isolute column which was eluted with ethyl acetate/dichloromethane (v/v; 1:1), and 2% methanol in ethyl acetate/dichloromethane (v/v; 1:1). The title compound was obtained as a pale yellow solid after trituration with diethyl ether (0.008 g, 18%). 1H-NMR (500 MHz, DMSO-d6) 2.19 (s, 3H, isoxazole CH3), 2.73 (s, 4H, piperazine N(CH2)2), 3.32 (s, 2H, NCH2CO), 3.73 (s, 4H, piperazine N(CH2)2), 3.83 (s, 3H, OCH3), 6.18 (s, 1H, isoxazole C—H), 7.11 (d, J=8.9 Hz, 2H) and 8.13 (d, J=8.8 Hz, 2H) (3,5-C6H4OMe and 2,6-C6H4OMe), 8.09 (s, 1H, imidazo[4,5-b]pyridine 5-H), 11.43 (br s, 1H, CONH), 13.38 (br s, 1H, imidazo[4,5-b]pyridine N—H);
