To a mixture of 2-amino-4,5-dichloro-3-nitropyridine (0.152 g, 0.73 mmol) and isopropanol (22 mL) was added 1-(4-chlorobenzyl)piperazine (0.165 g, 0.78 mmol) followed by diisopropylethylamine (0.17 mL, 0.97 mmol). The reaction mixture was heated at 45° C. for 18 h, then allowed to cool to room temperature, and diluted with isopropanol (5 mL). The precipitate was collected by filtration, washed with isopropanol and diethyl ether. The title compound was thus obtained as a yellow solid (0.215 g, 77%); 1H-NMR (500 MHz, DMSO-d6) 2.48 (br s, obscured by DMSO peak, 4H, piperazine C—H), 3.06 (br t, J=4.3 Hz, 4H, piperazine C—H), 3.52 (s, 2H, NCH2C6H4Cl), 6.95 (s, 2H, NH2), 7.35 (d, J=8.5 Hz, 2H) and 7.38 (d, J=8.5 Hz, 2H) (3,5-ArH and 2,6-ArH), 8.06 (s, 1H, 6-H); LC-MS (ESI, m/z): Rt=1.70 min-382, 384, 386 [(M+H)+, Cl2 isotopic pattern].
