A series of novel (imidazo [1, 2-b] pyridazin-6-yl) oxyalkylsulfonamides was synthesized and evaluated for the ability to inhibit platelet activating factor (PAF)-induced bronchoconstriction in guinea pigs. The compounds bearing a gem-dialkyl or a cycloalkylidene group at the 2 position of the sulfamoylpropyloxy group in the side chain were found to have potent activity. Among them, 3-(imidazo [1, 2-b] pyridazin-6-yl) oxy-2, 2-dimethylpropanesulfonamide (6) ...