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

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).

1. temperatureat reflux overnight
2. concentrationconcentrated in vacuo
3. customto remove EtOH
4. filtrationThe solid is collected by filtration
5. washwashed with acetone
6. customat 0-5° C.
7. extractionextracted with ethyl acetate (2×150 mL)
8. washThe combined layers are washed with brine
9. dry with materialdried over Na2SO4
10. filtrationfiltered
11. concentrationThe filtrate is concentrated in vacuo

ORD record

ord-9f66ec4e202c4bc79bd1d42bd3c32f87

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08901133B2