Trifluoroacetic acid → 4-Chloroindoline

HRID 2058501Notes

Reaction equation

HRID 2058501 reaction equation
[Cl:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH2:4][C:5](=O)[NH:6]2.[BH4-].[Na+].FC(F)(F)C(O)=O>O1CCOCC1>[Cl:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH2:4][CH2:5][NH:6]2

Participants

5

Reactant 3

HCID 6422Trifluoroacetic acidHCID 14806864-Chloro-1,3-dihydro-2H-indol-2-oneHCID 4311764Sodium borohydride

Product 1

HCID 30163064-ChloroindolineYield 77.4%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

5.5 g of 4-chlorooxindole was dissolved in 80 ml of dioxane and 6.2 g of sodium borohydride was suspended in the resulting solution. 12.7 ml of trifluoroacetic acid (d=1.48) was added thereto dropwise at room temperature while stirring. After heat-refluxing the mixture for 4.5 hours, the solvent was removed therefrom under reduced pressure. Water was added to the residue and the water-insoluble materials were removed by filtration and washed with diethyl ether. The filtrate was extracted with diethyl ether and the ether layer was dried over anhydrous sodium sulfate followed by removing the solvent. The residue was distilled under reduced pressure to obtain 3.9 g of 4-chloroindoline as a colorless oily product having a boiling point of 135° C. at 10 mm Hg.

Workup

  1. temperatureAfter heat-refluxing the mixture for 4.5 hours
  2. customthe solvent was removed
  3. additionWater was added to the residue
  4. customthe water-insoluble materials were removed by filtration
  5. washwashed with diethyl ether
  6. extractionThe filtrate was extracted with diethyl ether
  7. dry with materialthe ether layer was dried over anhydrous sodium sulfate
  8. customby removing the solvent
  9. distillationThe residue was distilled under reduced pressure

Sources & evidence

ORD record
ord-bc4193a30f9d4a839d2741e4bf1c6c0b
Source dataset
uspto-grants-1982_03
Patent number
US04317820

Reaction notes

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