反应详情

Dry methanol was saturated at 0° with gaseous hydrogen chloride. A sample of 0.576g. (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 1 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