反应详情

H2O (18 mL) was added dropwise to a stirred suspension of picolinic acid hydrochloride, compound 1 (157.9 g, 1.0 mol) in thionyl chloride (400 mL). The resulting mixture was heated under reflux for 4 days giving a clear orange solution. After cooling to ambient temperature, the solution was concentrated to a syrup and the residue coevaporated with toluene (2×500 mL). The residue was dissolved in toluene (1 L) and cooled to 0-5° C. Methanol (44.0 g, 1.0 mol) was added dropwise to the ice cold reaction mixture giving a heavy white precipitate. This precipitate was collected by filtration, washed with toluene (3×100 mL) and dried at 40° C. for 24 hr to give 176.5 g (85%) of compound 2 as a white crystalline solid.

1. temperatureThe resulting mixture was heated
2. temperatureunder reflux for 4 days
3. customgiving a clear orange solution
4. concentrationthe solution was concentrated to a syrup
5. dissolutionThe residue was dissolved in toluene (1 L)
6. temperaturecooled to 0-5° C
7. customgiving a heavy white precipitate
8. filtrationThis precipitate was collected by filtration
9. washwashed with toluene (3×100 mL)
10. customdried at 40° C. for 24 hr