反应详情

A suspension of 3.0 g of the compound from Example 2 and 0.1 g p-toluenesulfonic acid in 100 ml of dry toluene was refluxed in a flask equipped with a Dean-Stark apparatus. After being refluxed overnight the solution was concentrated and allowed to cool. The precipitate was filtered off to give 0.5 g light brown solid. The mother liquor was chromatographed over silica gel with 20:73:2:5, ethyl acetate:methylene chloride:methanol:THF to give additional product, m.p. 173°-177° C.;

1. temperaturewas refluxed in a flask
2. customequipped with a Dean-Stark apparatus
3. temperatureAfter being refluxed overnight the solution
4. concentrationwas concentrated
5. temperatureto cool
6. filtrationThe precipitate was filtered off