Ethyl (chloroformyl)acetate → Ethyl 6,8-dichloroimidazo[1,2-b]pyridazine-3-carboxylate

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Reaction Conditions

Reaction Steps

To a 250 mL round-bottomed flask was added ethyl 2-chloro-3-oxopropanoate (4.33 g, 28.8 mmol) and 4-bromo-6-chloropyridazin-3-amine (5 g, 23.99 mmol). The solution was heated to 90° C. for 16 hours. The solution was quenched with ethyl acetate and washed with water. The organic layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The crude material was purified by ISCO (10% ethyl acetate/dichloromethane; 80 g column) to give a mixture of ethyl 8-bromo-6-chloroimidazo[1,2-b]pyridazine-3-carboxylate and ethyl 6,8-dichloroimidazo[1,2-b]pyridazine-3-carboxylate (2.1 g, 29% yield). LC/MS, m/z 256.96 (M+1). HPLC Rt, 2.54 min. LC/MS, m/z 303.92 (M+1). HPLC Rt, 2.63 min. Waters Sunfire C18 column (4.6×50 mm) 0%-100% B. Solvent B: (90% MeOH, 10% H2O, 0.1% TFA). Solvent A: (10% MeOH, 90% H2O, 0.1% TFA). Gradient, start % B=0, final % B=100, gradient time 4 min, hold at 100% B 1 min, flow rate 4 mL/min.

Provenance & Evidence