General procedure for the synthesis of 3-bromo-6-chloroimidazo[1,2-b]pyridazine from 6-chloroimidazo[1,2-b]pyridazine: 478 mg (3.11 mmol) of 6-chloroimidazo[1,2-b]pyridazine was dissolved in 10 mL of chloroform under the protection of argon and cooled in an ice bath. Subsequently, 664 mg (3.73 mmol) of N-bromosuccinimide was slowly added. After addition, the reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the mixture was mixed with water and ethyl acetate, and the organic and aqueous phases were separated by the addition of saturated sodium bicarbonate solution. The aqueous phase was extracted three times with ethyl acetate. The organic phase was combined, washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure to afford the target product 3-bromo-6-chloroimidazo[1,2-b]pyridazine as an amorphous white solid, which could be used in subsequent reactions without further chromatographic purification.1H-NMR (CDCl3, molecular sieve dried): δ = 7.12 (d, 1H); 7.79 (s, 1H); 7.90 (d, 1H) ppm.
![6-Chloroimidazo[2,1-f]pyridazine](/CAS/GIF/6775-78-6.gif)
![3-Bromo-6-chloroimidazo[1,2-b]pyridazine](/CAS/GIF/13526-66-4.gif)