Hydrochloric Acid → 2-Chloro-6-propylimidazo[1,2-b]pyridazine

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Reaction Steps

2,6-Dichloroimidazo[1,2-b]pyridazine (0.50 g, 2.66 mmol) and bis(triphenylphosphine)nickel(II) dichloride (0.17 g, 0.27 mmol) were added to tetrahydrofuran (5.0 ml) under a nitrogen stream, and a solution of n-propylmagnesium bromide in tetrahydrofuran (2 M, 1.99 ml, 3.99 mmol) was added dropwise over 10 minutes to the mixture under ice-cooling. The mixture was stirred for 10 minutes under ice-cooling, and the reaction mixture was warmed to room temperature and stirred for 4 hours at room temperature. Cold water (50 ml) was added to the reaction mixture which was then acidified with dilute hydrochloric acid, and extracted with ethyl acetate. The extracts were washed with dilute hydrochloric acid, a saturated saline, an aqueous saturated sodium bicarbonate solution and a saturated saline in this order. The resulting organic layer was dried over anhydrous magnesium sulfate, filtrated and concentrated. The concentrated residue was purified by silica gel column chromatography (ethyl acetate:hexane=3:7) to give the title compound as white crystals. The yield was 0.21 g (40.4%).

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