反应详情

2-Chloro-3-pyridinecarboxylic acid, methyl ester (11) is prepared as follows: a suspension of 22.06 g (140 mmol) of 2-chloro-3-pyridinecarboxylic acid (10), 14.6 mL (154 mmol) of dimethyl sulfate, 29 g (210 mmol) of anhydrous powdered potassium carbonate, and 140 mL of acetone is stirred at room temperature overnight. The mixture is filtered, the salts are washed with acetone, and the filtrate is concentrated to an oil that is diluted with dichloromethane. The organic phase is washed with saturated aqueous sodium dicarbonate, dried, then filtered through a pad of silica gel (230-400 mesh). The filtrate is concentrated to give an oil that is distilled at 90°-91° C./0.17 mm to leave 19.9 g of the pure product as a colorless oil.

1. filtrationThe mixture is filtered
2. washthe salts are washed with acetone
3. concentrationthe filtrate is concentrated to an oil that
4. additionis diluted with dichloromethane
5. washThe organic phase is washed with saturated aqueous sodium dicarbonate
6. customdried
7. filtrationfiltered through a pad of silica gel (230-400 mesh)
8. concentrationThe filtrate is concentrated
9. customto give an oil that
10. distillationis distilled at 90°-91° C./0.17 mm