Reaktion #1252934

Reaktionsgleichung

decanoyl chloride

4-hydroxy-5,6-dihydro-6-methyl-2-pyrone

1,8-diazabicyclo(5,4,0)-undecene

Water

DBU

→

4-dodecanoyloxy-6-methyl-5,6-dihydro-2-pyrone

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling the reaction mixture in an ice-water bath
2. 2
   workup.ADDITIONAfter termination of the dropwise addition
3. 3
   workup.STIRRINGthe mixture was stirred at room temperature for 7 hours
4. 4
   Extraktionthe mixture was extracted with toluene
5. 5
   WaschenThe extract was washed with 5% HCl
6. 6
   Trocknenwith a saturated aqueous solution of sodium chloride, and dried over anhydrous magnesium sulfate
7. 7
   SonstigeThe solvent in the extract was evaporated under a reduced pressure
8. 8
   Sonstigeto purify the product, 4-dodecanoyloxy-6-methyl-5,6-dehydro-2-pyrone

Vorschrift

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.

Quelle