Efficient preparation of imidazo[1,2-b]pyridazines under Swern oxidative conditions

An efficient synthesis of new imidazo[1,2-b]pyridazine derivatives was effected by treating 3,6-dichloropyridazine with various 2-hydroxyethylamines following by imidazole ring formation under Swern oxidative conditions. Some mechanistic aspects of the cyclization step are discussed.