Chloroacetaldehyde → 8-Bromo-6-chloroimidazo(1,2-b)pyridazine

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Reaction Steps

To a stirred solution of 4-bromo-6-chloropyridazin-3-amine (D-2) (16 g, 77.3 mmol, 1.0 eq) in EtOH (200 mL), 2-chloroacetaldehyde (45% in water, 67.4 g, 386.6 mmol, 5.0 eq) is added and the resulting mixture is stirred at reflux overnight. The mixture is allowed to cool to RT and concentrated in vacuo to remove EtOH. The residue is slurried in acetone. The solid is collected by filtration and washed with acetone. The solid is suspended in water, neutralized with aqueous ammonia to adjust the pH to 8 at 0-5° C. and then extracted with ethyl acetate (2×150 mL). The combined layers are washed with brine, dried over Na2SO4 and filtered. The filtrate is concentrated in vacuo to afford the product, 8-bromo-6-chloroimidazo[1,2-b]pyridazine (D-3).

Provenance & Evidence