Hydrochloric Acid → 2-Chloro-6-propylimidazo[1,2-b]pyridazine

Temperature

5 °C

Under a nitrogen stream, 2,6-dichloroimidazo[1,2-b]pyridazine (0.50 g, 2.66 mmol) and iron(III) acetylacetonate (0.094 g, 0.27 mmol) were added to tetrahydrofuran (5.0 ml), and a solution of n-propylmagnesium bromide in tetrahydrofuran (2 M, 1.99 ml, 3.99 mmol) was added dropwise over 13 minutes to the mixture with stirring at 0 to 10° C. After stirring for 10 minutes under ice-cooling, the reaction mixture was warmed to room temperature and stirred for 6 hours at room temperature. The reaction mixture was poured onto ice-cold water, acidified with concentrated hydrochloric acid, and extracted with ethyl acetate. The extracts were washed with dilute hydrochloric acid, an aqueous saturated sodium bicarbonate solution and a saturated saline. The resulting organic layer was dried over anhydrous magnesium sulfate, filtrated and concentrated. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=3:7) to give the title compound as pale yellow crystals. The yield was 0.28 g (53.8%).

1. stirringAfter stirring for 10 minutes under ice-
2. temperaturecooling
3. temperaturethe reaction mixture was warmed to room temperature
4. stirringstirred for 6 hours at room temperature
5. additionThe reaction mixture was poured onto ice-cold water
6. extractionextracted with ethyl acetate
7. washThe extracts were washed with dilute hydrochloric acid
8. dry with materialThe resulting organic layer was dried over anhydrous magnesium sulfate
9. filtrationfiltrated
10. concentrationconcentrated
11. customThe residue was purified by silica gel column chromatography (ethyl acetate:hexane=3:7)

ORD record

ord-a845d94e2dee4ab0b86aae37116dbef7

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07307165B2