反应详情

1.28 g of 6-chloroimidazo[1,2-b]pyridazine-2-carboxylic acid was suspended in 12 ml of N,N-dimethylformamide; 1.16 g of N,N′-carbonyldiimidazole was added, followed by stirring at room temperature for 30 minutes. To the reaction mixture, 1.20 g of 2-aminoisobutyric acid ethyl ester hydrochloride and 1.00 ml of triethylamine were added, followed by stirring at room temperature for 16 hours. Water was added, the crystal precipitated was collected by filtration; the filtrate was extracted with ethyl acetate; the extract was washed with saturated saline and dried with magnesium sulfate. The dry product was concentrated under reduced pressure; the residue was combined with the above crystal collected by filtration and subjected to silica gel column chromatography and eluted with hexane:ethyl acetate (2:1). The desired fraction was collected and concentrated under reduced pressure to yield 1.20 g of the title compound.

1. stirringby stirring at room temperature for 16 hours
2. customthe crystal precipitated
3. filtrationwas collected by filtration
4. extractionthe filtrate was extracted with ethyl acetate
5. washthe extract was washed with saturated saline
6. dry with materialdried with magnesium sulfate
7. concentrationThe dry product was concentrated under reduced pressure
8. filtrationcollected by filtration
9. washeluted with hexane:ethyl acetate (2:1)
10. customThe desired fraction was collected
11. concentrationconcentrated under reduced pressure