Water → 6,9-Dimethyl-5,6,7,8,9,10-hexahydro-6,9-methanobenzocycloocten-11-one

HRID 1759604Notes

Reaction equation

HRID 1759604 reaction equation
Br[CH2:2][C:3]1[C:4]([CH2:9]Br)=[CH:5][CH:6]=[CH:7][CH:8]=1.[CH3:11][CH:12]1[CH2:16][CH2:15][CH:14]([CH3:17])[C:13]1=[O:18].N1CCCC1.O>C(#N)C>[CH3:11][C:12]12[C:13](=[O:18])[C:14]([CH3:17])([CH2:15][CH2:16]1)[CH2:9][C:4]1[CH:5]=[CH:6][CH:7]=[CH:8][C:3]=1[CH2:2]2

Participants

6

Reactant 4

HCID 962WaterHCID 31268PyrrolidineHCID 66665o-Bis(bromomethyl)benzeneHCID 968262,5-Dimethylcyclopentan-1-one2×

Product 1

HCID 130447816,9-Dimethyl-5,6,7,8,9,10-hexahydro-6,9-methanobenzocycloocten-11-one

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

α,α'-Dibromoxylene (30.3 g., 0.115 Mole) is dissolved in dry acetonitrile (250 ml.) and then, under nitrogen, the pyrrolidine enamine of 2,5-dimethylcyclopentanone (prepared from 2,5-dimethylcyclopentanone and pyrrolidine via the method of Stork) is added dropwise over one-half hour. The mixture is refluxed 2 days, cooled, water (100 ml.) is added; and the mixture is refluxed 1 hour, cooled, concentrated in vacuo, then extracted with ether (3×75 ml.). The combined extracts are washed with 10% HCl (50 ml.), brine (50 ml.), then dried and evaporated to yield 16 g. of solid, which recrystallized from dichloroethane-hexane gives pure title compound (9.7 g.). The mother liquors are chromatographed on silica gel (100 g.), eluting with ether-hexane (1:4) to give 5.8 g. more title compound, which yields 4.9 g. pure on crystallization from ether-hexane (64% total yield), m.p. 134°-135° C.

Workup

  1. additionis added dropwise over one-half hour
  2. temperatureThe mixture is refluxed 2 days
  3. temperaturecooled
  4. temperatureand the mixture is refluxed 1 hour
  5. temperaturecooled
  6. concentrationconcentrated in vacuo
  7. extractionextracted with ether (3×75 ml.)
  8. washThe combined extracts are washed with 10% HCl (50 ml.), brine (50 ml.)
  9. customdried
  10. customevaporated
  11. customto yield 16 g
  12. customof solid, which recrystallized from dichloroethane-hexane

Sources & evidence

ORD record
ord-90871f9625f14b4b89ddad12ad62829a
Source dataset
uspto-grants-1982_07
Patent number
US04341904

Reaction notes

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