Hydrochloric Acid → Furaneol

Beteiligte Stoffe

Reaktionsschritte

To a suspension of 113.4 g of sodium methylate in 750 g of methyl t-butyl ether was added at 5° C. in one hour 146 g of diethyl oxalate followed by a stirring period of one hour at 5° C. Then 204 g of diethyl 2-methyldiglycolate in two hours was added at 5° C. and the mixture was stirred for four hours at that temperature followed by a reflux period of three hours. The reaction mixture was added to 797 g of 8.9% hydrochloric acid solution at 20° C. and the pH of the resulting mixture was adjusted to 5 with 33% sodium hydroxide solution. To the separated upper layer was added with stirring 903 g of 17.8% sodium hydroxide solution at 20° C. The layers were allowed to settle and the separated lower layer was kept at 20° C. for 20 hours. Then, 200 g of water was added, 104 g of methyl bromide was introduced at 20° C. in one hour, and the mixture was stirred for another hour; and the pH of the solution was adjusted to 6.5 by the addition of concentrated hydrochloric acid solution. Extraction with methyl t-butyl ether yielded 95 g of 2,5-dimethyl-4-hydroxy-3[2H] furanone of 97.3% purity (molar overall yield 72.2%).

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