A Convenient Synthesis of 3-Hydroxy-4H-pyran-4-one Derivatives Having a Halo or Hydroxy Group at the 5-Position
摘要:
The reaction of 4,5-epoxy-4-halo-6-methoxy-2-methyl-tetrahydropyran-3-ones (4b and 5b) in acidic media was examined and the following results were found: The reaction of 4b or 5b with 1% sulfuric acid afforded a mixture of 3,5-dihydroxy-4H-pyran-4-one (1b) and 5-halo-3-hydroxy-4H-pyran-4-one (2b or 3b), but the use of concentrated acid formed the corresponding 5-halo-4H-pyran-4-one (2b or 3b) only. The reaction was applicable for a general method for synthesizing 3,5-disubstituted 4H-pyran-4-ones (1, 2, and 3).
Improved procedure for the synthesis of 6-alkoxy-2,3-dihydro-6h-pyran-3-ones (2,3-dideoxy-dl-pent-2-enopyranos-4-uloses). Neat conversion into polyfunctionalized cyclopentenones
作者:Bernd Mucha、H. Martin、R. Hoffmann
DOI:10.1016/s0040-4039(01)80725-5
日期:1989.1
MUCHA, BERND;HOFFMANN, M. MARTIN R., TETRAHEDRON LETT., 30,(1989) N4, C. 4489-4492