反应详情

A mixture of 5-formyl-pyrazine-2-carboxylic acid methyl ester (325 mg, 1.56 mmol), ethylene glycol (100 μL, 1.79 mmol), and p-toluenesulfonic acid monohydrate (30 mg, 0.157 mmol) in benzene (10 mL) was heated under reflux with a Dean-Stark condenser for 17 h. The mixture was cooled and diluted with benzene (25 mL). The organic layer was washed with a saturated aqueous sodium bicarbonate solution (25 mL) and a saturated aqueous sodium chloride solution (25 mL). Each aqueous wash was back-extracted with a small portion of benzene. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to afford 5-[1,3dioxolan-2-yl-pyrazine-2-carboxylic acid methyl ester as an orange-red oil (250 mg).

1. temperaturewas heated
2. temperatureunder reflux with a Dean-Stark condenser for 17 h
3. temperatureThe mixture was cooled
4. washThe organic layer was washed with a saturated aqueous sodium bicarbonate solution (25 mL)
5. washEach aqueous wash
6. extractionwas back-extracted with a small portion of benzene
7. dry with materialThe combined organic layers were dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo