Potassium Hydroxide → 3a-butyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one

HRID 2113661Notes

Reaction equation

HRID 2113661 reaction equation
[CH2:1]([C:5]1([CH2:18][C:19](=[O:21])[CH3:20])[CH2:14][CH2:13][C:12]2[C:7](=[CH:8][CH:9]=[C:10]([O:15][CH3:16])[CH:11]=2)[C:6]1=O)[CH2:2][CH2:3][CH3:4].[OH-].[K+]>CCO.O>[CH2:1]([C:5]12[CH2:18][C:19](=[O:21])[CH:20]=[C:6]1[C:7]1[C:12]([CH2:13][CH2:14]2)=[CH:11][C:10]([O:15][CH3:16])=[CH:9][CH:8]=1)[CH2:2][CH2:3][CH3:4]

Participants

5

Reactant 2

HCID 14797Potassium HydroxideHCID 586040662-butyl-6-methoxy-2-(2-oxopropyl)-3,4-dihydro-1(2H)-naphthalenone

Product 1

HCID 586040693a-butyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent2×HCID 962WaterSolvent

Procedure

A solution of crude 2-butyl-6-methoxy-2-(2-oxopropyl)-3,4-dihydro-1(2H)-naphthalenone (888 mg, ˜3 mmol) in EtOH (15 mL) was treated with freshly prepared 2N KOH in EtOH (1.5 mL, 3 mmol). The resulting solution was placed under a N2 atmosphere and heated at reflux for 17 hours. After cooling, the mixture was diluted with water (100 mL) and extracted with EtOAc (3×100 mL). The extracts were washed with brine, dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by Biotage™ (Charlottesville, Va.) flash chromatography on a 40S (4×7 cm) silica gel column, eluting with 1000 mL portions of 19:1 and 10:1 hexane-EtOAc. The product-containing fractions were evaporated under vacuum to provide 3a-butyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one as an oil.

Workup

  1. temperatureheated
  2. temperatureat reflux for 17 hours
  3. temperatureAfter cooling
  4. extractionextracted with EtOAc (3×100 mL)
  5. washThe extracts were washed with brine
  6. dry with materialdried over MgSO4
  7. filtrationfiltered
  8. concentrationconcentrated under vacuum
  9. customThe residue was purified by Biotage™ (Charlottesville, Va.) flash chromatography on a 40S (4×7 cm) silica gel column
  10. washeluting with 1000 mL portions of 19:1 and 10:1 hexane-EtOAc
  11. customThe product-containing fractions were evaporated under vacuum

Sources & evidence

ORD record
ord-a61192ed16134446927166eb43fe1778
Source dataset
uspto-grants-2008_10
Patent number
US07432284B2

Reaction notes

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