Indole-2-carboxaldehyde → HCID 67937868, compound

HRID 1165799Notes

Reaction equation

HRID 1165799 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[C:2]1[CH:10]=O.[Na]>[Cl-].C([P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)C1C=CC=CC=1.C(O)C>[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[C:2]1/[CH:10]=[CH:3]\[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

5

Reactant 2

HCID 96389Indole-2-carboxaldehydeHCID 5360545Sodium

Product 1

HCID 67937868HCID 67937868, compound

Reagents, catalysts & solvents 2

HCID 70671Benzyltriphenylphosphonium chlorideCatalystHCID 702EthanolSolvent2×

Procedure

2.0 g (13.7 mmole) 2-indolealdehyde and 5.3 g (13.7 mmole) benzyltriphenylphosphonium chloride are heated to a boil in 30 ml dry ethanol. A freshly prepared solution of 0.32 g (13.9 mmole) sodium in 15 ml ethanol is added dropwise thereto within about 1.5 hours. Subsequently, it is boiled under reflux for one hour, after cooling the solvent is distilled off, and the residue is partitioned between dichloromethane and water. The organic phase is dried over sodium sulphate, evaporated, and the residue chromatographed o silica gel with cyclohexane/toluene 7:3. The fraction with the Rf of 0.4 is isolated. One obtains (Z)-1-(2-indolyl)-2-phenylethylene in the form of a pale yellow oil which, in the case of drying in a vacuum, crystallizes. The fraction with the Rf of 0.2 is evaporated, the residue stirred with cyclohexane, and the crystals formed are filtered off. One obtains (E)-1-(2-indolyl)-2-phenylethylene in the form of almost colorless crystals of the mp 205°-206° C. The preparation of the 2-indolealdehyde takes place according to the statements in the literature (Arch Pharm 310, 975, 1977) from 2-indolecarboxylic acid esters.

Workup

  1. temperatureunder reflux for one hour
  2. temperatureafter cooling the solvent
  3. distillationis distilled off
  4. customthe residue is partitioned between dichloromethane and water
  5. dry with materialThe organic phase is dried over sodium sulphate
  6. customevaporated
  7. customthe residue chromatographed o silica gel with cyclohexane/toluene 7:3
  8. customThe fraction with the Rf of 0.4 is isolated

Sources & evidence

ORD record
ord-c2276902f1b2434da23c2ed541530053
Source dataset
uspto-grants-1990_03
Patent number
US04912107

Reaction notes

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