Yield:13526-66-4 100%

Reaction Conditions:

Stage #1:6-chloroimidazo[1,2-b]pyridazine with N-Bromosuccinimide in chloroform at 0 - 20;
Stage #2: with water;sodium hydrogencarbonate in chloroform;ethyl acetate

Steps:

3-Bromo-6-chloroimidazo[1,2-b]pyridazine 478 mg (3.11 mmol) of 6-chloroimidazo[1,2-b]pyridazine were introduced into 10 ml of chloroform under argon and, while cooling in ice, 664 mg (3.73 mmol) of N-bromo-succuinimide were added. After the addition was complete, the reaction mixture was stirred at room temperature overnight. The reaction mixture was then mixed with water and ethyl acetate and, after addition of saturated sodium bicarbonate solution, the phases were separated. The aqueous phase was extracted three more times with ethyl acetate. The combined organic phases were then washed with sat. sodium chloride solution and dried over sodium sulfate. In the final removal of the solvent in vacuo, the desired product was isolated in quantitative yield in the form of an amorphous white solid which was employed without further chromatographic purification in subsequent reactions.¹H-NMR (CDCl₃, stored over molecular sieves): δ=7.12 (d, 1H); 7.79 (s, 1H); 7.90, (d, 1H) ppm.

References:

PRIEN, Olaf;Eis, Knut;Bader, Benjamin;Guenther, Judith;Von Bonin, Arne US2009/93475, 2009, A1 Location in patent:Page/Page column 6

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