Methanesulfonic Acid → 5,6-Dimethoxy-3-phenyl-3,4-dihydronaphthalen-1(2H)-one

HRID 233385Notes

Reaction equation

HRID 233385 reaction equation
[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[CH:7][CH:6]=[CH:5][C:4]=1[CH2:11][CH:12]([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[CH2:13][C:14](O)=[O:15].CS(O)(=O)=O>FC(F)(F)C(O)=O>[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[CH:7][CH:6]=[C:5]2[C:4]=1[CH2:11][CH:12]([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[CH2:13][C:14]2=[O:15]

Participants

4

Reactant 2

HCID 6395Methanesulfonic AcidHCID 124785434-(2',3'-Dimethoxyphenyl) 3-phenylbutyric acid

Product 1

HCID 124785445,6-Dimethoxy-3-phenyl-3,4-dihydronaphthalen-1(2H)-oneYield 77%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

4-(2',3'-Dimethoxyphenyl)-3-phenylbutyric acid (13.3 g, 44.3 mmol), from Step 4, was treated with 14 mL (216 mmol) of methanesulfonic acid and 200 mL of trifluoroacetic acid at 60° C. for 1.5 h. After cooling the reaction mixture, the trifluoroacetic acid was removed in vacuo and ice water was added to the residue. Methylene chloride was added and the layers were separated. The organic layer was washed with 1N aqueous sodium hydroxide solution, water and brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was recrystallized three times from methanol to give 9.6 g (77% yield) of 5,6-dimethoxy-3-phenyl-1,2,3,4-tetrahydronaphthalen-1-one, m.p. 126°-128° C.; 1H NMR spectrum was identical to the spectrum reported for the product of Step 6 of Method A, Example 1.

Workup

  1. temperatureAfter cooling the reaction mixture
  2. customthe trifluoroacetic acid was removed in vacuo and ice water
  3. additionwas added to the residue
  4. additionMethylene chloride was added
  5. customthe layers were separated
  6. washThe organic layer was washed with 1N aqueous sodium hydroxide solution, water and brine
  7. dry with materialdried over anhydrous magnesium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated under reduced pressure
  10. customThe residue was recrystallized three times from methanol

Sources & evidence

ORD record
ord-c4590203623e4f8c81c1e69be4ca86b6
Source dataset
uspto-grants-1997_01
Patent number
US05591884

Reaction notes

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