| 摘要 |
PURPOSE:To prepare menthone, by heating easily available 7-methyl-5-oxooctyl acetate with an alkaline aqueous solution, treating the reaction product with a phosphorus halide, and heating the treated reaction product with an alkaline substance in the presence of a phase transfer catalyst. CONSTITUTION:3,7-Dimethyl-5-oxooctyl acetate expressed by formula (b) obtained easily by radical addition reaction of isopentenyl acetate expressed by formula (a) with 3-methylbutanal expressed by formula (c) is heated with an alkaline aqueous solution to give 8-hydroxy-2,6-dimethyl-4-octane, which is then treated with a phosphorus halide to afford an 8-halo-2,6-dimethyl-4-octanone. The resultant intermediate is then heated with an alkaline substance in the presence of a phase transfer catalyst, e.g. dibenzo-18-crown-6, or a polar aprotic solvent, e.g. benzene, to give the aimed menthone. USE:A synthetic raw material for menthol.
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