反应详情

To a stirred solution of imidazo[1,2-a]pyridine-8-carboxylic acid (3.8 g, 23 mmol) in methanol (100 mL) is added thionylchloride (8.36 g, 70.3 mmol) and the mixture is warmed at reflux. After 8 hours, the reaction mixture is cooled to room temperature and quenched with saturated aqueous NaHCO3, and extracted with EtOAc (3×250 mL). The combined organic layers are washed with water, brine, dried over Na2SO4 and concentrated. The crude material is purified by silica gel chromatography eluting with 3% MeOH in CH2Cl2 to afford imidazo[1,2-a]pyridine-8-carboxylic acid methyl ester. Mp: 71-73° C.

1. temperaturethe mixture is warmed
2. temperatureat reflux
3. customquenched with saturated aqueous NaHCO3
4. extractionextracted with EtOAc (3×250 mL)
5. washThe combined organic layers are washed with water, brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated
8. customThe crude material is purified by silica gel chromatography
9. washeluting with 3% MeOH in CH2Cl2