Triethylamine → rac-3,4-Dihydro-2,5,7,8-tetramethyl-2-{[5-(2-pyridinyl)-2-thienyl]ethynyl}-2H-1-benzopyran-6-ol

HRID 654493Notes

Reaction equation

HRID 654493 reaction equation
[C:1]([C:3]1([CH3:17])[CH2:8][CH2:7][C:6]2[C:9]([CH3:16])=[C:10]([OH:15])[C:11]([CH3:14])=[C:12]([CH3:13])[C:5]=2[O:4]1)#[CH:2].Br[C:19]1[S:23][C:22]([C:24]2[CH:29]=[CH:28][CH:27]=[CH:26][N:25]=2)=[CH:21][CH:20]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(N(CC)CC)C>C(#N)C>[CH3:17][C:3]1([C:1]#[C:2][C:19]2[S:23][C:22]([C:24]3[CH:29]=[CH:28][CH:27]=[CH:26][N:25]=3)=[CH:21][CH:20]=2)[CH2:8][CH2:7][C:6]2[C:9]([CH3:16])=[C:10]([OH:15])[C:11]([CH3:14])=[C:12]([CH3:13])[C:5]=2[O:4]1

Participants

6

Reactant 4

HCID 8471TriethylamineHCID 11776TriphenylphosphineHCID 7364832-(5-Bromo-2-thienyl)pyridineHCID 14478563rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6ol

Product 1

HCID 15171831rac-3,4-Dihydro-2,5,7,8-tetramethyl-2-{[5-(2-pyridinyl)-2-thienyl]ethynyl}-2H-1-benzopyran-6-olYield 51.4%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A mixture of 2.3 g of rac-3,4-dihydro-2-ethynyl2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol, 3.6 g (15 mmol) of 2-(5-bromo-2-thienyl)pyridine, 0.39 g of triphenylphosphine, 95 mg of cuprous iodide, 3 ml of triethylamine and 100 ml of acetnitrile was degassed with argon for 10 minutes. Palladium acetate, 110 mg, was then added and the mixture was stirred at room temperature for 18 hrs. After evaporation under reduced pressure, the residue was partitioned between methylene chloride and water. The organic layer was dried and evaporated and the residue was chromatographed over 140 g of silica gel using 5% of ethyl acetate in methylene chloride. The combined clean fractions were evaporated and the residue was crystallized from ether/hexane to yield 2 g of colorless crystals with m.p. 159°-162°. The analytical sample was recrystallized from ethanol and had m.p. 160°-162°.

Workup

  1. customwas degassed with argon for 10 minutes
  2. additionPalladium acetate, 110 mg, was then added
  3. customAfter evaporation under reduced pressure
  4. customthe residue was partitioned between methylene chloride and water
  5. customThe organic layer was dried
  6. customevaporated
  7. customthe residue was chromatographed over 140 g of silica gel using 5% of ethyl acetate in methylene chloride
  8. customThe combined clean fractions were evaporated
  9. customthe residue was crystallized from ether/hexane

Sources & evidence

ORD record
ord-8651c1f0213e4497874652ab3b1091e3
Source dataset
uspto-grants-1992_07
Patent number
US05132310

Reaction notes

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