反应详情

A solution of sodium nitrite (2.73 g, 39.6 mmol) in water (15 mL) was added slowly to a solution of commercially available (Maybridge) 2,6-dichloro-4-methyl-nicotinamide (4.5 g, 22 mmol) in concentrated sulfuric acid resulting in evolution of heat and brown gas. The mixture was stirred at room temperature for 15 min, and then heated to 60° C. for 7 h. The solution was cooled to 0° C. and then water (15 mL) was added. The resulting white precipitate was collected by filtration and washed with hexane. The aqueous filtrate was extracted with EtOAc (3×) and the combined organic extracts were dried over MgSO4 and concentrated in vacuo. The residue was combined with the white precipitate to afford 2,6-dichloro-4-methyl-nicotinic acid (4.39 g, 97%) as a white solid: LCMS RT: 1.20 min, MH+: 206.3.

1. temperatureof heat
2. temperatureheated to 60° C. for 7 h
3. temperatureThe solution was cooled to 0° C.
4. filtrationThe resulting white precipitate was collected by filtration
5. washwashed with hexane
6. extractionThe aqueous filtrate was extracted with EtOAc (3×)
7. dry with materialthe combined organic extracts were dried over MgSO4
8. concentrationconcentrated in vacuo