A CONVENIENT SYNTHESIS OF 3-HYDROXY-4H-PYRAN-4-ONE DERIVATIVES HAVING A HALO OR HYDROXY GROUP AT THE 5-POSITION
The reaction of 4,5-epoxy-4-halo-6-methoxy-2-methyltetrahydropyran-3-ones (4b, 5b) in acidic media was examined and the following results were found: The reaction of 4b or 5b with 1percent sulfuric acid afforded a mixture of 3,5-dihydroxy-4H-pyran-4-one (