反应详情

Under a nitrogen atmosphere, oxalyl chloride (2.41 g, 0.019 mole) was added dropwise, slowly, to a stirred and chilled (10° C.) suspension of (S)-2-(4-chlorophenyl)-α-methyl-3H-imidazo[4,5-b]pyridine-3-acetic acid (5.0 g, 0.0166 mole) in anhydrous dimethylformamide (75 ml). The suspension was stirred at room temperature for 30 minutes and then an additional portion of oxalyl chloride (0.73 g, 0.0057 mole) was added. The resulting solution was stirred at room temperature for 45 minutes and then added slowly to a suspension of N,N-dimethyl-1,4-benzenediamine dihydrochloride (3.97 g, 0.0019 mole) and triethylamine (7.7 g, 0.076 mole) in anhydrous dimethylformamide (150 ml). The reaction mixture was stirred at room temperature overnight under nitrogen and protected from light. The solution was then poured into 400 ml of ice water. The resulting solid was collected by filtration, rinsed with water, dissolved in hot isopropyl alcohol, filtered, and cooled to room temperature. Upon addition of water, solid precipitated. The solid was collected by filtration, dissolved in hot tetrahydrofuran, and made acidic with ethereal hydrogen chloride. The solid was collected by filtration, rinsed with isopropyl ether, and dried under high vacuum at 50° C. to give 4.0 g (47%) of title compound, mp 186°-190° C.

1. temperaturechilled
2. stirringThe suspension was stirred at room temperature for 30 minutes
3. stirringThe resulting solution was stirred at room temperature for 45 minutes
4. stirringThe reaction mixture was stirred at room temperature overnight under nitrogen
5. filtrationThe resulting solid was collected by filtration
6. washrinsed with water
7. dissolutiondissolved in hot isopropyl alcohol
8. filtrationfiltered
9. additionUpon addition of water, solid
10. customprecipitated
11. filtrationThe solid was collected by filtration
12. dissolutiondissolved in hot tetrahydrofuran
13. filtrationThe solid was collected by filtration
14. washrinsed with isopropyl ether
15. customdried under high vacuum at 50° C.