To a solution of 3 ,6-dichloro-4- methoxypyridazine (30 g, 167.59 mmol, 1.00 equiv) and ammonium formate (3 1 g, 491.63 mmol, 2.93 equiv) in MeOH (500 mL) was added 10% palladium on carbon (3 g) catalyst. The mixture was stirred under 1 atmosphere of at rt overnight. The catalyst was removed by filtration and the filtrate was concentrated under vacuum. The residue was triturated in 500 mL of DCM MeOH ( 10: 1 ) and the solid material was filtered out. The filtrate was concentrated under vacuum and the residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (2:1 to 1: 1) to give 1 5 g (81%) of 4-methoxypyridazine as a brown oil. TLC: petroleum ether: ethyl acetate=2: 1 , Rf=0.1 .
