反应详情

200 g of 5-cyano-2-hydroxy-6-methyl-3-pyridine-carboxylic acid, ethyl ester (1 mol) are refluxed with stirring in 750 ml of phosphorous oxychloride for 5 hours. The excess of phosphorous oxychloride is removed in vacuo and the residue poured in 1 kg of ice. 2-chloro-5-cyano-6-methyl-3-pyridine-carboxylic acid, ethyl ester crystallizes and is filtered off. Yield 170 g (76%); m.p. 43°-45° C. (petrol ether).

1. customThe excess of phosphorous oxychloride is removed in vacuo
2. additionthe residue poured in 1 kg of ice
3. custom2-chloro-5-cyano-6-methyl-3-pyridine-carboxylic acid, ethyl ester crystallizes
4. filtrationis filtered off