Potassium Carbonate → tert-butyl 6-(4-methylphenyl)-2H-1-benzopyran-3-carboxylate

HRID 566014Notes

Reaction equation

HRID 566014 reaction equation
Br[C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:9][C:8]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])=[CH:7][C:6]=2[CH:18]=1.B([O-])([O-])O[C:21]1[CH:26]=[CH:25][C:24]([CH3:27])=[CH:23][CH:22]=1.C(=O)([O-])[O-].[K+].[K+]>C1(C)C(CCO)=CC=CC=1.O.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[CH3:27][C:24]1[CH:25]=[CH:26][C:21]([C:2]2[CH:3]=[CH:4][C:5]3[O:10][CH2:9][C:8]([C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])=[CH:7][C:6]=3[CH:18]=2)=[CH:22][CH:23]=1

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 10566979Tert-butyl 6-bromo-2H-chromene-3-carboxylateHCID 866453334-Methylphenyl borate

Product 1

HCID 10615821tert-butyl 6-(4-methylphenyl)-2H-1-benzopyran-3-carboxylateYield 74.1%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 66602552Toluene-ethanol waterSolvent

Procedure

Under argon atmosphere, a solution of tert-butyl 6-bromo-2H-1-benzopyran-3-carboxylate (5.00 g), 4-methylphenyl borate (2.62 g) and potassium carbonate (4.44 g) in toluene-ethanol-water (160-16-16 ml) was stirred at room temperature for 1 hour. To the reaction mixture was added tetrakistriphenylphosphinepalladium (0.56 g), and the mixture was refluxed for 14 hours and cooled to room temperature. The organic layer was washed with saturated sodium chloride solution, dried with magnesium sulfate and concentrated. The residue was separated and purified with column chromatography (ethyl acetate/hexane=1:19) to give pale yellow crystals, which were recrystallized from ethanol to give tert-butyl 6-(4-methylphenyl)-2H-1-benzopyran-3-carboxylate (3.84 g) as pale yellow crystals.

Workup

  1. temperaturethe mixture was refluxed for 14 hours
  2. washThe organic layer was washed with saturated sodium chloride solution
  3. dry with materialdried with magnesium sulfate
  4. concentrationconcentrated
  5. customThe residue was separated
  6. custompurified with column chromatography (ethyl acetate/hexane=1:19)
  7. customto give pale yellow crystals, which
  8. customwere recrystallized from ethanol

Sources & evidence

ORD record
ord-508742d8bf7e45b8a757c618091e7d54
Source dataset
uspto-grants-2001_01
Patent number
US06172061B2

Reaction notes

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