Hydrochloric Acid → 3,7-Dibromodibenzo(b,d)thiophene

HRID 444661Notes

Reaction equation

HRID 444661 reaction equation
[H-].[Al+3].[Li+].[H-].[H-].[H-].[Br:7][C:8]1[CH:9]=[CH:10][C:11]2[C:15]3[CH:16]=[CH:17][C:18]([Br:20])=[CH:19][C:14]=3[S:13](=O)(=O)[C:12]=2[CH:23]=1.CCOCC.Cl>C(Cl)(Cl)Cl.O>[Br:20][C:18]1[CH:17]=[CH:16][C:15]2[C:11]3[CH:10]=[CH:9][C:8]([Br:7])=[CH:23][C:12]=3[S:13][C:14]=2[CH:19]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 3283Diethyl EtherHCID 40718983,7-Dibromo-dibenzothiophene 5,5-dioxideHCID 21226445Aluminium lithium hydride2×

Product 1

HCID 8037593,7-Dibromodibenzo(b,d)thiopheneYield 48.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6212ChloroformSolvent

Procedure

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.

Workup

  1. temperaturethe resulting mixture is refluxed
  2. stirringthe mixture is thoroughly stirred
  3. customthe organic layer is separated
  4. extractionThe aqueous layer is further extracted with chloroform (200 ml×2)
  5. extractionthe chloroform extract
  6. washthe combined organic layer is washed with water (200 ml) and saturated brine (200 ml)
  7. dry with materialdried over calcium chloride
  8. distillationThe solvent is distilled off
  9. customcolorless crystals thus obtained
  10. customare recrystallized from ethyl acetate+ethanol (16:3)

Sources & evidence

ORD record
ord-e8993a482e264607916821b1a435b3a0
Source dataset
uspto-grants-2013_07
Patent number
US08475984B1

Reaction notes

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