反应详情

A solution of 2-(5-methyl-2-thienyl)-3H-imidazo[4,5-b]pyridine-3-acetic acid (5.0 g, 0.0183 mole) and 1,1'-carbonyldiimidazole (2.97 g, 0.0183 mole) in tetrahydrofuran (100 ml) was stirred at room temperature for 3 hours with a stream of nitrogen bubbling through it. A solution of dipropylamine (5.56 g, 0.055 mole) in tetrahydrofuran (7 ml) was added and the reaction mixture was stirred overnight at room temperature. The solvents were evaporated and the residue was partitioned between water and ethyl acetate. The layers were separated and the aqueous layer was extracted again with ethyl acetate. The combined organic layer was washed twice with water, twice with a 5% potassium hydroxide solution, and twice again with water. The organic layer was dried over magnesium sulfate, treated with charcoal, filtered, and evaporated to give a solid which was dissolved in hot isopropyl alcohol and filtered while hot. Addition of water and cooling caused a solid to precipitate. The solid was dissolved again in hot isopropyl alcohol with charcoal, filtered while hot and brought to the cloud point by addition of water. Upon cooling, solid precipitated which was collected by filtration, rinsed with water, and dried under high vacuum at 50° C. overnight to give 2.28 g (35%) of title compound, mp 125°-127° C.

1. customThe solvents were evaporated
2. customthe residue was partitioned between water and ethyl acetate
3. customThe layers were separated
4. extractionthe aqueous layer was extracted again with ethyl acetate
5. washThe combined organic layer was washed twice with water, twice with a 5% potassium hydroxide solution
6. dry with materialThe organic layer was dried over magnesium sulfate
7. additiontreated with charcoal
8. filtrationfiltered
9. customevaporated
10. customto give a solid which
11. filtrationfiltered while hot
12. additionAddition of water
13. temperaturecooling
14. customto precipitate
15. dissolutionThe solid was dissolved again in hot isopropyl alcohol with charcoal
16. filtrationfiltered while hot and
17. additionbrought to the cloud point by addition of water
18. temperatureUpon cooling
19. customsolid precipitated which
20. filtrationwas collected by filtration
21. washrinsed with water
22. customdried under high vacuum at 50° C. overnight