PRODUCTION OF 1,6,6-TRIMETHYL-3-(1-HYDROXYETHYL)-2-OXABICYCLO(4.3.0)NON-4-EN-8-ONE

PURPOSE:Only an operation, bringing 4-(2,3-epoxybutylidene)-3,5,5-trimethyl-2- cyclohexene-1-one, which is readily obtained from isophorone through 4-step operations in low costs, into contact with a base in the presence of water, gives the titled compound as a flavor material for tobacco. CONSTITUTION:4-(2,3-Epoxybutylidene)-3,5,5-trimethyl-2-cyclohexene-1-one of formulaI(wavy line represents trans and/or cis isomeric bondages), after treatment with an acid such as acetic or hydrochloric acid or no treatment, is brought into contact with a base such as sodium hydroxide or potassium hydroxide in the presence of water, preferably a mixture thereof with an organic solvent to give the objective compound of formula II (wavy line may contain stereoisomeric bondage). The compound of formulaIis obtained from isophorone by its isomerization, silylation, condensation, dehydration and epoxidation.