Bromine → 1-bromo-3a-ethyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one

HRID 2113655Notes

Reaction equation

HRID 2113655 reaction equation
[CH2:1]([C:3]12[CH2:17][C:16](=[O:18])[CH:15]=[C:4]1[C:5]1[C:10]([CH2:11][CH2:12]2)=[CH:9][C:8]([O:13][CH3:14])=[CH:7][CH:6]=1)[CH3:2].C([O-])(O)=O.[Na+].[Br:24]Br>>[Br:24][C:15]1[C:16](=[O:18])[CH2:17][C:3]2([CH2:1][CH3:2])[CH2:12][CH2:11][C:10]3[C:5](=[CH:6][CH:7]=[C:8]([O:13][CH3:14])[CH:9]=3)[C:4]=12

Participants

4

Reactant 3

HCID 24408BromineHCID 516892Sodium BicarbonateHCID 58604065HCID 58604065, compound

Product 1

HCID 586040711-bromo-3a-ethyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one

Procedure

A solution of 3a-ethyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one (415 mg, 1.7 mol) in CCL4 (5.1 mL) was treated with NaHCO3 (714 mg, 8.5 mmol). The mixture was cooled in an ice bath, purged with N2, stirred, and treated with Br2 (0.088 mL, 1.7 mmol) to give an unstirrable orange gum. The mixture was sonicated for one minute, swirled in an ice bath for two minutes, and then stirred at 0-5° C. for 75 minutes. The mixture was then partitioned between CH2Cl2 and water (50 mL each). The organic phase was washed with saturated aqueous Na2S2O3 and brine, dried over MgSO4, filtered, and evaporated under vacuum. The crude product was purified by Biotage™ (Charlottesville, Va.) flash chromatography on a 40M (4×15 cm) silica gel column, eluting with 5:1 hexane-EtOAc, to provide 1-bromo-3a-ethyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one as a white foam.

Workup

  1. temperatureThe mixture was cooled in an ice bath
  2. custompurged with N2
  3. customto give an unstirrable orange gum
  4. customThe mixture was sonicated for one minute
  5. stirringstirred at 0-5° C. for 75 minutes
  6. customThe mixture was then partitioned between CH2Cl2 and water (50 mL each)
  7. washThe organic phase was washed with saturated aqueous Na2S2O3 and brine
  8. dry with materialdried over MgSO4
  9. filtrationfiltered
  10. customevaporated under vacuum
  11. customThe crude product was purified by Biotage™ (Charlottesville, Va.) flash chromatography on a 40M (4×15 cm) silica gel column
  12. washeluting with 5:1 hexane-EtOAc

Sources & evidence

ORD record
ord-c5975afbf9f74b088a6912028db84f7b
Source dataset
uspto-grants-2008_10
Patent number
US07432284B2

Reaction notes

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