反应详情

温度

92 °C

Stir a mixture of sodium ethoxide (90 g, 1.32 mol, 2 eq), toluene (0.5 L, 5 vol), and ethyl acetate (0.2 L, 1.98 mol, 3 eq) in a 2 L flask equipped with reflux condenser, mechanical stirrer, and nitrogen inlet. After 1 h, add 6-methyl-pyridine-2-carboxylic acid methyl ester (Cheung, Y, Tetrahedron Lett. 1979, 40, 3809-10; 100 g, 0.66 mol). Heat the mixture at reflux (92° C.) for 20 h. Cool the mixture to room temperature and acidify with glacial acetic acid to pH 6. Wash the resulting gel with water (0.5 L). Separate the layers and extract the aqueous layer with toluene (1×0.5 L) Dry the combined organic layers (sodium sulfate), filter, and concentrate in vacuo to yield the subtitled product (154 g) as a dark oil in 86% purity by HPLC analysis. MS ES+ m/e 208 (M+1).

1. customequipped
2. temperaturewith reflux condenser, mechanical stirrer, and nitrogen inlet
3. temperatureHeat the mixture
4. temperatureCool the mixture to room temperature
5. washWash the resulting gel with water (0.5 L)
6. customSeparate the layers
7. extractionextract the aqueous layer with toluene (1×0.5 L)
8. dry with materialDry the combined organic layers (sodium sulfate)
9. filtrationfilter
10. concentrationconcentrate in vacuo