反应详情

Next, this methoxy methylene Meldrum's acid (25 g, 0.13 mol) was dissolved in chloroform (200 ml), followed by adding 2N-HCl (50 ml), agitating the mixture at room temperature, allowing it to still standing, separating the chloroform layer, saturating the aqueous layer with sodium chloride, extracting the solution with chloroform, combining the extract solution with the previously obtained chloroform solution, drying over anhydrous magnesium sulfate, filtering off the drying agent, and distilling off chloroform under reduced pressure to obtain raw formyl Meldrum's acid as residue, adding ether thereto, filtering off, further washing with ether, vaporizing the remaining ether and recrystallizing the resulting crystals from a mixed solvent of dichloromethanehexane to obtain formyl Meldrum's acid in the form of colorless crystals (20.5 g, yield 89%) having a m.p. of 95°-96° C.

1. customseparating the chloroform layer
2. concentrationsaturating the aqueous layer with sodium chloride
3. extractionextracting the solution with chloroform
4. dry with materialdrying over anhydrous magnesium sulfate
5. filtrationfiltering off the drying agent
6. distillationdistilling off chloroform under reduced pressure
7. customto obtain raw formyl Meldrum's acid as residue
8. filtrationfiltering off
9. washfurther washing with ether
10. customrecrystallizing the resulting crystals from a mixed solvent of dichloromethanehexane