O-Phenylenediamine → 2-(3,3-Dimethyl-2,3-dihydro-2-oxo-(1H)-6-indolyl)benzimidazole

HRID 36400Notes

Reaction equation

HRID 36400 reaction equation
[CH3:1][C:2]1([CH3:14])[C:10]2[C:5](=[CH:6][C:7]([C:11]#[N:12])=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:13].[C:15]1(N)[CH:20]=[CH:19][CH:18]=[CH:17][C:16]=1[NH2:21]>O.N>[CH3:1][C:2]1([CH3:14])[C:10]2[C:5](=[CH:6][C:7]([C:11]3[NH:21][C:16]4[CH:17]=[CH:18][CH:19]=[CH:20][C:15]=4[N:12]=3)=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:13]

Participants

5

Reactant 2

HCID 7243O-PhenylenediamineHCID 146240543,3-Dimethyl-2-oxoindoline-6-carbonitrile

Product 1

HCID 150778042-(3,3-Dimethyl-2,3-dihydro-2-oxo-(1H)-6-indolyl)benzimidazoleYield 10.3%

Reagents, catalysts & solvents 2

HCID 222AmmoniaSolventHCID 962WaterSolvent

Procedure

One heated 3,3-dimethyl-2,3-dihydro-2-oxo-(1H)-6-indolecarbonitrile (2.6 g, preparation described in DE-A-3,818,830) and ortho-phenylenediamine (2.6 g) in polyphosphoric acid for 6 h at 160° C. One allowed to cool to 80°-90° C., added ice thereto, diluted with water to a volume of 1.2 l and neutralised with conc. ammonia. One extracted with a mixture of dichloromethane:methanol=10:1, removed the solvent in a vacuum and purified the residue column chromatographically (silica gel 60, dichloromethane:methanol. ammonia=20:1). One obtained 0.4 g of grey crystals which one recrystallised from ethanol/water. One obtained 195 mg of the title compound with the m.p. 326°-330° C.

Workup

  1. temperatureto cool to 80°-90° C.
  2. additionadded ice
  3. extractionOne extracted with a mixture of dichloromethane
  4. custommethanol=10:1, removed the solvent in a vacuum
  5. custompurified the residue column chromatographically (silica gel 60, dichloromethane:methanol. ammonia=20:1)

Sources & evidence

ORD record
ord-29941636c96d4be6828b9c339444c3ce
Source dataset
uspto-grants-1995_05
Patent number
US05414088

Reaction notes

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