Reaktion #3081

Reaktionsgleichung

(+)-8-chloro-6-hydroxy-octanoic acid

pyridine

thionyl chloride

→

(-)-6,8-dichloro-octanoic acid

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was then refluxed for 1 hour
2. 2
   SonstigeThe organic phase was then removed
3. 3
   Waschenwashed with 20 ml water
4. 4
   SonstigeThe aqueous phase was then removed
5. 5
   Extraktionextracted twice with 20 ml diethylether
6. 6
   TrocknenThe combined ether extracts were dried over magnesium sulfate
7. 7
   SonstigeAfter that, the solvent was evaporated under vacuum

Vorschrift

To a solution of 2.4 g (12.3 mmoles) of (+)-8-chloro-6-hydroxy-octanoic acid (+)-(VI) and 0.05 g (0.6 mmoles) of pyridine in 30 ml toluene, 3.3 g (27.7 mmoles) of thionyl chloride were added slowly. The mixture was then refluxed for 1 hour. The reaction mixture was cooled to room temperature and added to 50 ml ice water. The organic phase was then removed, washed with 20 ml water and stirred for 4 hours with 30 ml of 2N NaOH. The aqueous phase was then removed, adjusted to a pH of 1 with 3N HCl and extracted twice with 20 ml diethylether. The combined ether extracts were dried over magnesium sulfate. After that, the solvent was evaporated under vacuum. (-)-6,8-dichloro-octanoic acid (-)-(VII) was obtained in a yield of 2.1 g (80% of the theoretical yield). [α]D20 =-30.6° (c=1; benzene).

Quelle