Sulfuric Acid → 3-Bromo-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-one

HRID 274065Notes

Reaction equation

HRID 274065 reaction equation
N[C:2]1[CH:13]=[CH:12][C:5]2[CH2:6][CH2:7][CH2:8][C:9](=[O:11])[CH2:10][C:4]=2[CH:3]=1.S(=O)(=O)(O)O.[N+]([O-])([O-])=O.[Na+].[Br-:24].[Na+]>C(O)(=O)C.O.Br.C(Cl)(Cl)Cl>[Br:24][C:2]1[CH:13]=[CH:12][C:5]2[CH2:6][CH2:7][CH2:8][C:9](=[O:11])[CH2:10][C:4]=2[CH:3]=1

Participants

9

Reactant 4

HCID 1118Sulfuric AcidHCID 24268Sodium NitrateHCID 253881Sodium BromideHCID 20094815HCID 20094815, compound

Product 1

HCID 200948363-Bromo-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-oneYield 49.3%

Reagents, catalysts & solvents 4

HCID 176Acetic AcidSolventHCID 260Hydrogen BromideSolventHCID 962WaterSolvent3×HCID 6212ChloroformSolvent

Procedure

To a solution of 3-amino-6,7,8,9-tetrahydro-5H-benzocyclohepten-6-one (9.42 g) in a mixture of acetic acid (1.85 ml), conc. sulfuric acid (9.24 ml) and water (24.56 ml) was added portionwise a solution of sodium nitrate (4.08 g) in water (6.00 ml) with ice salt bath cooling and the whole was stirred for 1 hour. The solution was added to a solution of cuprous bromide (10.02 g) and sodium bromide (9.40 g) in a mixture of 47% hydrobromic acid (27.72 ml) and water (61.52 ml) at 75° C. and the whole was stirred for 0.5 hour. After cooling, ice water (100 ml) and chloroform (200 ml) were added to the mixture. The insoluble material was filtered off. The organic layer was separated and the aqueous layer was extracted with chloroform. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, and treated with active carbon (0.65 g). The solution was evaporated in vacuo and the residue was purified by column chromatography on silica gel with toluene as an eluent to give 3-bromo-6,7,8,9-tetrahydro-5H-benzocyclohepten-6-one (6.34 g).

Workup

  1. temperaturecooling
  2. stirringthe whole was stirred for 0.5 hour
  3. temperatureAfter cooling
  4. filtrationThe insoluble material was filtered off
  5. customThe organic layer was separated
  6. extractionthe aqueous layer was extracted with chloroform
  7. washThe combined organic layer was washed with brine
  8. dry with materialdried over anhydrous sodium sulfate
  9. additiontreated with active carbon (0.65 g)
  10. customThe solution was evaporated in vacuo
  11. customthe residue was purified by column chromatography on silica gel with toluene as an eluent

Sources & evidence

ORD record
ord-a98a9c7cf0b54a32a7b74e5d1fd68f8e
Source dataset
uspto-grants-1995_02
Patent number
US05387710

Reaction notes

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