反应详情

2(1-hydroxy ethyl)-2,3,5-trimethoxy-2,5-dihydrofuran (2.82 g, 0.015 moles) in 2 ml methanol was added to 15 ml of formic acid over 5 minutes. To the well stirred solution was then added 20 ml of water and the reaction heated to reflux for 1 hour. After cooling, the reaction was extracted with chloroform and the chloroform concentrated to yield 1.5 g maltol, which was recrystallized from methanol to yield the pure white solid, m.p. 159°-160° C. Hydrochloric acid, hydrobromic acid, p-toluene sulfonic acid and acidic ion exchange resins can be used in place of formic acid in this Example.

1. temperaturethe reaction heated
2. temperatureto reflux for 1 hour
3. temperatureAfter cooling
4. extractionthe reaction was extracted with chloroform
5. concentrationthe chloroform concentrated