Triethylamine → 3,4-dihydro-2,5,7,8-tetramethyl-2-(2-phenylethynyl)-2H-1-benzopyran-6-ol

HRID 256833

Reaction equation

HRID 256833 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].I[C:19]1[CH:24]=[CH:23][CH:22]=[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[CH:24]=[CH:23][CH:22]=[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 11575IodobenzeneHCID 11776TriphenylphosphineHCID 14478563rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6ol

Product 1

HCID 151718093,4-dihydro-2,5,7,8-tetramethyl-2-(2-phenylethynyl)-2H-1-benzopyran-6-olYield 68.5%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A mixture of 2.3 g (10 mmol) of rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol, 3.06 g (15 mmol) of iodobenzene, 0.39 g of triphenylphosphine, 95 mg of cuprous iodide, 3 ml of triethylamine and 100 ml of acetonitrile was degassed with argon for 10 minutes. Palladium acetate, 110 mg (0.5 mmol), was then added and stirring under argon was continued for 3 hours. The reaction mixture was evaporated under reduced pressure and the residue was partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution. The organic phase was separated, dried over sodium sulfate and evaporated. The crude product was chromatographed over 100 g of silica gel (Merck 70-230 mesh) using methylene chloride for elution. The clean fractions were combined and evaporated and the residue was crystallized from hexane to yield 2.1 g (68%) of rac-3,4-dihydro-2,5,7,8-tetramethyl-2-(phenylethynyl)-2H-1-benzopyran-6-ol with m.p. 109°-111° C. The analytical sample was recrystallized from hexane and had m.p. 111°-113° C. Anal. Calcd. for C21H22O2 : C, 82.32; H, 7.24 Found: C, 82.02; H, 7.30

Workup

  1. customwas degassed with argon for 10 minutes
  2. additionPalladium acetate, 110 mg (0.5 mmol), was then added
  3. customThe reaction mixture was evaporated under reduced pressure
  4. customthe residue was partitioned between methylene chloride and saturated aqueous sodium bicarbonate solution
  5. customThe organic phase was separated
  6. dry with materialdried over sodium sulfate
  7. customevaporated
  8. customThe crude product was chromatographed over 100 g of silica gel (Merck 70-230 mesh)
  9. washfor elution
  10. customevaporated
  11. customthe residue was crystallized from hexane

Sources & evidence

ORD record
ord-6b4ef1300ba540c39eb697ce44582a6e
Source dataset
uspto-grants-1993_11
Patent number
US05260294

Linked notes

Loading…