Preparation of gamma-pyrones

摘要

Maltol (3-hydroxy-2-methyl-gamma-pyrone) is prepared from furfural through intermediates (a) 1-(2-furyl)-1-ethanol; (b) 2-(1-hydroxyethyl)-2,5-dialkoxy-2,5-dihydrofuran; (c) alkyl or aralkyl-2-methyl-2H-pyran-3(6H)-one; and (d) 2-alkyl or aralkyl-4-methyl-3,7-dioxabicyclo[4.1.0]heptan-5-one. Pyromeconic acid (3-hydroxy-gamma-pyrone), ethyl maltol (3-hydroxy-2-ethyl-gamma-pyrone) and other valuable 2-substituted-3-hydroxy-gamma-pyrones are prepared in an analogous manner from furfural.