Potassium Carbonate → 2-[(1H-indol-4-yl)-ethenyl]-phenol

HRID 1906188Notes

Reaction equation

HRID 1906188 reaction equation
[Br-].[OH:2][C:3]1[CH:28]=[CH:27][CH:26]=[CH:25][C:4]=1[CH2:5][P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C([Li])CCC.[CH:34]([C:36]1[CH:44]=[CH:43][CH:42]=[C:41]2[C:37]=1[CH:38]=[CH:39][NH:40]2)=O.C(=O)([O-])[O-].[K+].[K+]>O1CCCC1.CCCCCC.O>[NH:40]1[C:41]2[C:37](=[C:36]([CH:34]=[CH:5][C:4]3[CH:25]=[CH:26][CH:27]=[CH:28][C:3]=3[OH:2])[CH:44]=[CH:43][CH:42]=2)[CH:38]=[CH:39]1

Participants

8

Reactant 4

HCID 11430Potassium CarbonateHCID 333703Indole-4-carboxaldehydeHCID 2724142(2-Hydroxybenzyl)triphenylphosphonium bromideHCID 178418339Butyllithium

Product 1

HCID 541413862-[(1H-indol-4-yl)-ethenyl]-phenolYield 91.3%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolvent

Procedure

Under an inert atmosphere, 31 g of ortho hydroxybenzyltriphenyl-phosphonium bromide were suspensed in 350 ml of tetrahydrofuran and then over a period of one hour, 86 ml of a 1.6 M solution of butyllithium in hexane were added. The mixture stood for 30 minutes with stirring and then over 30 minutes, a solution of 5 g of 4-formyl-indole in 150 ml of tetrahydrofuran was added. The mixture was stirred for 24 hours and then was diluted with 500 ml of water. Potassium carbonate was added to saturation, and the mixture was extracted with ethyl acetate. The fractions with Rf=0.20 were isolated by chromatography on silica (eluent: methylene chloride) and the crystals obtained were triturated in methylene chloride, then filtered and dried under reduced pressure to obtain 7.4 g of 2-[(1H-indol-4-yl)-ethenyl]-phenol melting at 140° C., and after recrystallization from methylene chloride at 142° C.

Workup

  1. waitThe mixture stood for 30 minutes
  2. waitover 30 minutes
  3. stirringThe mixture was stirred for 24 hours
  4. extractionthe mixture was extracted with ethyl acetate
  5. customThe fractions with Rf=0.20 were isolated by chromatography on silica (eluent: methylene chloride)
  6. customthe crystals obtained
  7. customwere triturated in methylene chloride
  8. filtrationfiltered
  9. customdried under reduced pressure

Sources & evidence

ORD record
ord-e169a4adddba4fe08700351a69289aba
Source dataset
uspto-grants-1987_03
Patent number
US04650811

Reaction notes

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