Sulfuric Acid → 7-dimethylamino-6,7-dihydro [5H] benzocycloheptene

HRID 372541Notes

Reaction equation

HRID 372541 reaction equation
S(=O)(=O)(O)O.[CH3:6][N:7]([CH3:20])[CH:8]1[CH2:14][CH2:13][C:12]2[CH:15]=[CH:16][CH:17]=[CH:18][C:11]=2[CH:10](O)[CH2:9]1.[OH-].[NH4+].[Cl-].[Na+]>O1CCOCC1>[CH3:6][N:7]([CH3:20])[CH:8]1[CH:9]=[CH:10][C:11]2[CH:18]=[CH:17][CH:16]=[CH:15][C:12]=2[CH2:13][CH2:14]1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 5234Sodium ChlorideHCID 14923Ammonium HydroxideHCID 203844387-dimethylamino-5-hydroxy-6,7,8,9-tetrahydro [5H] benzocycloheptene

Product 1

HCID 30468617-dimethylamino-6,7-dihydro [5H] benzocyclohepteneYield 49.3%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent2×

Procedure

16 ml of 18 N sulfuric acid were added to a refluxing mixture of 8 g of 7-dimethylamino-5-hydroxy-6,7,8,9-tetrahydro [5H] benzocycloheptene and 80 ml of dioxane and after one half hour of reflux, another 80 ml of dioxane were added thereto. The mixture was refluxed another 30 minutes and was then cooled. The pH was raised above 10 by addition of concentrated ammonium hydroxide and the mixture was saturated with sodium chloride and was extracted with ethyl acetate. The organic extracts were washed with aqueous sodium chloride and then were dried and evaporated to dryness. The residue was chromatographed over silica gel and was eluted with a 7-3-1 cyclohexane-ethyl acetate-triethylamine mixture to obtain 3.6 g of 7-dimethylamino-6,7-dihydro [5H] benzocycloheptene.

Workup

  1. temperatureof reflux
  2. temperatureThe mixture was refluxed another 30 minutes
  3. temperaturewas then cooled
  4. extractionwas extracted with ethyl acetate
  5. washThe organic extracts were washed with aqueous sodium chloride
  6. customwere dried
  7. customevaporated to dryness
  8. customThe residue was chromatographed over silica gel
  9. washwas eluted with a 7-3-1 cyclohexane-ethyl acetate-triethylamine mixture

Sources & evidence

ORD record
ord-5f83c836beed4d1488aaeefbff9e6ff2
Source dataset
uspto-grants-1978_05
Patent number
US04091115

Reaction notes

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