Ammonia → 7,7-Dimethyl-2-(isopropenyl)-6,7-dihydro-3 H,5H-pyrrolo[2,3-f]benzimidazol-6-one

HRID 568811Notes

Reaction equation

HRID 568811 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][C:10]=1[NH2:11])[NH:7][C:6](=[O:12])[C:5]2([CH3:14])[CH3:13].[C:15](O)(=O)[C:16]([CH3:18])=[CH2:17].N>CS(C)=O>[CH3:13][C:5]1([CH3:14])[C:4]2[C:8](=[CH:9][C:10]3[NH:11][C:17]([C:16]([CH3:18])=[CH2:15])=[N:1][C:2]=3[CH:3]=2)[NH:7][C:6]1=[O:12]

Participants

5

Reactant 3

HCID 222AmmoniaHCID 4093Methacrylic AcidHCID 135892372H-Indol-2-one, 5,6-diamino-1,3-dihydro-3,3-dimethyl-

Product 1

HCID 1784398427,7-Dimethyl-2-(isopropenyl)-6,7-dihydro-3 H,5H-pyrrolo[2,3-f]benzimidazol-6-one

Reagents, catalysts & solvents 1

HCID 679Dimethyl SulfoxideSolvent

Procedure

3.0 g. (15.7 mmole) 5,6-diamino-3,3-dimethylindolin-2-one and 1.37 g. (15.9 mmole) methacrylic acid are heated for 30 minutes at 200° C. in 28 g. polyphosphoric acid. Thereafter, the reaction mixture is mixed with 40 ml. ice water. The brown suspension obtained is adjusted, while cooling with ice, to pH 8 with 45 ml. concentrated aqueous ammonia solution. The substance is filtered off with suction and washed with a little water. There are obtained 3.74 g. of crude product which are dissolved in 5 ml. dimethyl sulphoxide, diluted with 15 ml. methanol and purified over a silica gel column (7.50 g. gel; elution agent: dichloromethane/methanol 10:1 v/v). There is obtained 0.6 g. (14% of theory) of the title compound; m.p. 270°-273° C.

Workup

  1. additionThereafter, the reaction mixture is mixed with 40 ml
  2. customThe brown suspension obtained
  3. temperaturewhile cooling with ice, to pH 8 with 45 ml
  4. filtrationThe substance is filtered off with suction
  5. washwashed with a little water
  6. customThere are obtained 3.74 g
  7. dissolutionof crude product which are dissolved in 5 ml
  8. custommethanol and purified over a silica gel column (7.50 g. gel; elution agent: dichloromethane/methanol 10:1 v/v)
  9. customThere is obtained 0.6 g

Sources & evidence

ORD record
ord-8b63d94b5db944b989688b464e19b823
Source dataset
uspto-grants-1988_03
Patent number
US04730003

Reaction notes

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