Water → 4-Dodecanoyloxy-6-methyl-5,6-dihydro-2-pyrone

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Reaction Steps

To a solution of 5.13 g (0.040 mole) of 4-hydroxy-5,6-dihydro-6-methyl-2-pyrone and 6.70 g (0.044 mole) of 1,8-diazabicyclo(5,4,0)-undecene (hereinafter referred to as DBU) in 100 ml of toluene was added dropwise 8.39 g (0.044 mole) of decanoyl chloride with stirring and cooling the reaction mixture in an ice-water bath. After termination of the dropwise addition, the mixture was stirred at room temperature for 7 hours. Water was added to the reaction mixture and the mixture was extracted with toluene. The extract was washed with 5% HCl and then with a saturated aqueous solution of sodium chloride, and dried over anhydrous magnesium sulfate. The solvent in the extract was evaporated under a reduced pressure, and the residue was subjected to silica gel column chromatography to purify the product, 4-dodecanoyloxy-6-methyl-5,6-dehydro-2-pyrone. To a solution of 4-dodecanoyloxy-6-methyl-5,6-dihydro-2-pyrone, thus obtained, in 20 ml of toluene was added 0.06 g of 4-pyrolidinopyridine. The mixture was refluxed for 3 hours and the solvent was removed by evaporation under a reduced pressure. The residue was purified by silica gel column chromatography to obtain 1.6 g (yield: 14%) of 3-decanoyl-6-methyltetrahydropyran-2,4-dione, m.p. 62°-63° C.

Provenance & Evidence