General procedure for the synthesis of 3,6-dichloropyridazin-4-amine from 3,4,6-trichloropyridazine:
Example 24A: 3,4,6-Trichloropyridazine (25 g, 136 mmol) was added to a 500 mL stainless steel pressure flask containing 14.8 N ammonium hydroxide solution (200 mL). The reaction mixture was stirred at 75°C for 16 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the solid product was collected by filtration to afford 17 g (76% yield) of the target compound 3,6-dichloropyridazin-4-amine. The product characterization data were as follows: 1H NMR (400 MHz, DMSO-d6) δ ppm 7.16 (s, 2H), 6.82 (s, 1H); MS (ESI+) m/z 164 (M+H)+.
