反应详情

Dry methanol was saturated at 0° with gaseous hydrogen chloride. A sample of 0.576 g. (2.46 mmoles) of 2-hydroxy-9-methoxy-2,3-dihydro-7H-furo[3,2-g][1]benzopyran-7-one was dissolved in the resultant solution, and the dark reaction was allowed to proceed at room temperature for one hour. The solvent was evaporated and the residue was taken up in ethyl acetate/benzene. 1:4 and filtered through 50 g. silica, eluting with the same solvent system. Fractions containing the product, which is first eluted, were combined and evaporated to give pure 2,9-dimethoxy-2,3-dihydro-7H-furo[3,2-g][1]benzopyran-7-one as a white solid. Recrystallization from methanol afforded an analytical sample of this product, mp 131°-132°.

1. customthe dark reaction
2. customThe solvent was evaporated
3. filtration1:4 and filtered through 50 g
4. washsilica, eluting with the same solvent system
5. additionFractions containing the product, which
6. customevaporated