Reaktion #64338

Reaktionsgleichung

hydrochloric acid

sodium hydroxide

diethyl oxalate

sodium hydroxide

sodium methylate

methyl t-butyl ether

→

2,5-dimethyl-4-hydroxy-3[2H] furanone

Ausbeute 74.2%

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITfollowed by a reflux period of three hours
2. 2
   workup.ADDITIONTo the separated upper layer was added
3. 3
   Sonstigethe separated lower layer
4. 4
   workup.WAITwas kept at 20° C. for 20 hours
5. 5
   workup.ADDITIONThen, 200 g of water was added
6. 6
   workup.ADDITION104 g of methyl bromide was introduced at 20° C. in one hour
7. 7
   workup.STIRRINGthe mixture was stirred for another hour
8. 8
   workup.ADDITIONand the pH of the solution was adjusted to 6.5 by the addition of concentrated hydrochloric acid solution
9. 9
   ExtraktionExtraction with methyl t-butyl ether

Vorschrift

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%).

Quelle