Hydrochloric Acid → Ethyl 6-n-propylimidazo[1,2-b]pyridazin-2-ylcarboxylate

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Reaction Steps

Ethyl 6-chloroimidazo[1,2-b]pyridazin-2-ylcarboxylate (1.00 g, 4.43 mmol) and [1,3-bis(diphenylphosphino)propane]nickel (II) dichloride (0.24 g, 0.44 mmol) were added to tetrahydrofuran (8.0 ml) under a nitrogen stream, and a solution of n-propylzinc bromide in tetrahydrofuran (0.5 M, 13.3 ml, 6.65 mmol) was added dropwise thereto with stirring under ice-cooling. The mixture was stirred for 20 minutes under ice-cooling and for 0.5 hour at room temperature, and cold water (50.0 ml) was added to the reaction mixture which was then acidified with dilute hydrochloric acid. The reaction solution was extracted with ethyl acetate, and the extracts were combined and washed with dilute hydrochloric acid and a saturated saline solution. The resulting organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated. The concentrated residue was purified by silica gel column chromatography (acetone:hexane=1:3) to give the title compound as white crystals. The yield was 0.77 g (74.8%).

Provenance & Evidence