Réaction #1504041

Équation de réaction

anisaldehyde

Cis-1,2-cyclohexane dimethanol

sodium hydroxide

glycine

sodium hydroxide

sodium hydroxide

sodium hydroxide

Glycine

→

(1R,6S)-(+)-8-oxabicyclo[4.3.0]nonan-7-one

Rendement 87.4%

Solvants

acetone

ethanol

ethyl acetate methylene chloride

water

Conditions de réaction

Traitement

1. 1
   workup.DISSOLUTIONAfter the enzyme has dissolved the pH
2. 2
   workup.STIRRINGthe reaction mixture is stirred at 30° C
3. 3
   AutreDuring the reaction
4. 4
   Températureheating)
5. 5
   Extractionextracted 3 times with 250 ml of methylene chloride
6. 6
   Extractionfollowed by continuous extraction with 1 liter of ethyl acetate for 24 hours
7. 7
   ExtractionThe ethyl acetate extract
8. 8
   Séchageis dried over anhydrous magnesium sulfate
9. 9
   Autreevaporated under reduced pressure

Mode opératoire

Glycine (18.8 grams) is dissolved in 2 liters of deionized water, and the pH is adjusted by the addition of 10% sodium hydroxide to 9.0. Cis-1,2-cyclohexane dimethanol (10.0 grams) is dissolved in 150 ml of acetone added to the glycine solution with stirring, followed by the addition of β-NAD+ (Sigma, 0.5 grams). To the resulting solution is added horse liver alcohol dehydrogenase (Sigma, 250 mg, approximately 400 units). After the enzyme has dissolved the pH is readjusted to 9.0 with 10% sodium hydroxide, and the reaction mixture is stirred at 30° C. During the reaction, the pH is maintained at 9.0 with a pH-stat by the addition of 10% sodium hydroxide. Progress of the reaction is monitored by thin layer chromatography (Silica gel plates, eluent 1:1 ethyl acetate-methylene chloride; visualization by dipping in a solution of 5% anisaldehyde in ethanol and heating). When the reaction is complete as judged by thin layer chromatography, the reaction mixture is adjusted to a pH of 13 with 10 M sodium hydroxide and then extracted 3 times with 250 ml of methylene chloride. The pH of the aqueous mixture is then adjusted to 3 with concentrated HCl, followed by continuous extraction with 1 liter of ethyl acetate for 24 hours. The ethyl acetate extract is dried over anhydrous magnesium sulfate and evaporated under reduced pressure to yield (1R,6S)-(+)-8-oxabicyclo[4.3.0]nonan-7-one (8.5 grams) as a yellowish oil.

Source