Réaction #531843

Équation de réaction

lithium aluminum hydride

lithium aluminum hydride

3,7-dibromodibenzothiophene dioxide

ether

hydrochloric acid

→

3,7-dibromodibenzothiophene

Rendement 48.1%

Solvants

Chloroform

Water

Conditions de réaction

Traitement

1. 1
   Températurethe resulting mixture is refluxed
2. 2
   workup.STIRRINGthe mixture is thoroughly stirred
3. 3
   Autrethe organic layer is separated
4. 4
   ExtractionThe aqueous layer is further extracted with chloroform (200 ml×2)
5. 5
   Extractionthe chloroform extract
6. 6
   Lavagethe combined organic layer is washed with water (200 ml) and saturated brine (200 ml)
7. 7
   Séchagedried over calcium chloride
8. 8
   workup.DISTILLATIONThe solvent is distilled off
9. 9
   Autrecolorless crystals thus obtained
10. 10
    Autreare recrystallized from ethyl acetate+ethanol (16:3)

Mode opératoire

In a 500-ml flask, lithium aluminum hydride (4.1 g) is slowly introduced in small amounts over 50 minutes into a mixture of 3,7-dibromodibenzothiophene dioxide (20 g) and anhydrous ether (200 ml) in an ice bath, and the resulting mixture is refluxed and stirred for 2 hours. Water (200 ml) is added thereto to deactivate lithium aluminum hydride. Chloroform (200 ml) and concentrated hydrochloric acid (40 ml) are added thereto, the mixture is thoroughly stirred, and the organic layer is separated. The aqueous layer is further extracted with chloroform (200 ml×2), the chloroform extract is combined with the organic layer, and the combined organic layer is washed with water (200 ml) and saturated brine (200 ml), and dried over calcium chloride. The solvent is distilled off, and colorless crystals thus obtained are recrystallized from ethyl acetate+ethanol (16:3). Thus, 8.8 g of 3,7-dibromodibenzothiophene is obtained.

Source