Thioguaiacol → 6-(2-methoxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran

HRID 1416179Notes

Reaction equation

HRID 1416179 reaction equation
Br[C:2]1[CH:14]=[CH:13][C:5]2[O:6][C:7]([CH3:12])([CH3:11])[C:8]([CH3:10])=[CH:9][C:4]=2[CH:3]=1.CC(C)([O-])C.[Na+].[CH3:21][O:22][C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][C:24]=1[SH:29]>C(O)C.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.[Pd]>[CH3:21][O:22][C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][C:24]=1[S:29][C:2]1[CH:14]=[CH:13][C:5]2[O:6][C:7]([CH3:12])([CH3:11])[C:8]([CH3:10])=[CH:9][C:4]=2[CH:3]=1

Participants

6

Reactant 3

HCID 23642ThioguaiacolHCID 149560896-Bromo-2,2,3-trimethyl-2H-benzo[b]pyranHCID 23676156Sodium t-butoxide

Product 1

HCID 187828656-(2-methoxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyranYield 68.8%

Reagents, catalysts & solvents 2

HCID 11979704Tetrakis(triphenylphosphine)palladiumCatalystHCID 702EthanolSolvent

Procedure

6-Bromo-2,2,3-trimethyl-2H-benzo[b]pyran (9.6 g) (see Preparation 4) was dissolved in absolute ethanol (200 ml), then sodium tert-butoxide (11.0 g), 2-methoxybenzenethiol (5.3 g) and tetrakis(triphenylphosphine)palladium(O) (0.45 g) were added and the mixture heated under reflux under a nitrogen atmosphere for 24 hours. The solvent was removed under reduced pressure and the residue was dissolved in dichloromethane and washed with water. The organic layer was dried (anhydrous sodium sulphate), the solvent was removed under reduced pressure and the crude product was chromatographed first on silica using 1:1 hexane: dichloromethane as the eluent and then on silica using 24:1 hexane: ethyl acetate as the eluent to yield 6-(2-methoxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (8.12 g) as an oil.

Workup

  1. temperaturethe mixture heated
  2. temperatureunder reflux under a nitrogen atmosphere for 24 hours
  3. customThe solvent was removed under reduced pressure
  4. dissolutionthe residue was dissolved in dichloromethane
  5. washwashed with water
  6. dry with materialThe organic layer was dried (anhydrous sodium sulphate)
  7. customthe solvent was removed under reduced pressure
  8. customthe crude product was chromatographed first on silica using 1:1 hexane

Sources & evidence

ORD record
ord-8727b9e4a4e0442585cec1e8df2986e9
Source dataset
uspto-grants-1999_06
Patent number
US05912244

Reaction notes

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