反应详情

A mixture of dimethyl sulfoxide (500 ml), benzene (375 ml) and sodium hydride (52 g of a 57% oil dispersion, 1.24 mole), was heated at 75° under nitrogen until all the solid dissolved giving a clear gray-green solution. The solution was cooled in an icebath and 4-methoxycoumarin (75 g, 0.425 mole) was added. The reaction mixture was stirred at room temperature for one hour and poured into excess anhydrous ether. Th ether was decanted from the insoluble salts, which were washed several times with fresh ether. The salts were dissolved in a minimum of cold water and acidified with ice-cold 5 N hydrochloric acid. The acidified solution was extracted with chloroform (5×40 ml). The extracts were combined, dried over Na2SO4, and evaporated at reduced pressure to give a solid product. Recrystallization from absolute ethanol gave white crystals (57.3 g, 61%), m.p. 142°-146°.

1. temperaturewas heated at 75° under nitrogen until all the solid
2. dissolutiondissolved
3. customgiving a clear gray-green solution
4. additionwas added
5. customTh ether was decanted from the insoluble salts, which
6. washwere washed several times with fresh ether
7. dissolutionThe salts were dissolved in a minimum of cold water
8. extractionThe acidified solution was extracted with chloroform (5×40 ml)
9. dry with materialdried over Na2SO4
10. customevaporated at reduced pressure
11. customto give a solid product
12. customRecrystallization from absolute ethanol