2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 12,13-Dihydro-6-methyl-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione

HRID 1418632Notes

Reaction equation

HRID 1418632 reaction equation
[CH3:1][N:2]1[CH2:17][C:16]2[C:15]3[C:14]4[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=4)[NH:8][C:7]=3[C:6]3[NH:18][C:19]4[C:20](=O)[CH2:21][CH:22]=[CH:23][C:24]=4[C:5]=3[C:4]=2[C:3]1=[O:26].C(C1C(=O)C(Cl)=C(Cl)C(=[O:32])C=1C#N)#N.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[CH3:1][N:2]1[C:3](=[O:26])[C:4]2[C:5]3[C:24]4[C:19](=[CH:20][CH:21]=[CH:22][CH:23]=4)[NH:18][C:6]=3[C:7]3[NH:8][C:9]4[CH:10]=[CH:11][CH:12]=[CH:13][C:14]=4[C:15]=3[C:16]=2[C:17]1=[O:32]

Participants

5

Reactant 3

HCID 67752,3-Dichloro-5,6-dicyano-1,4-benzoquinoneHCID 521998p-Toluenesulfonic acid monohydrateHCID 86753906HCID 86753906, compound

Product 1

HCID 548235012,13-Dihydro-6-methyl-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

12-(2-carbamoylethyl)-6,7,12,13-tetrahydro-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole is obtained in the form of dark yellow crystals which decompose from 310° C. The 12-(2-carboxyethyl)-6,7,12,13-tetrahydro-5,7-dioxoindolo[2,3-a]furano[3,4-c]carbazole used as starting material is prepared as follows: 980 mg (2.39 mmol) 12-(2-Carbamoylethyl)-6,7,12,13-tetrahydro-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo-[3,4-c]carbazole are heated under reflux for 1.5 hours in 200 ml 15% methanolic potassium hydroxide solution. After cooling, the reaction mixture is filtered, the filtrate is acidified with 2N hydrochloric acid and the product which precipitates out is filtered off and washed with water. 12-(2-Carboxyethyl)-6,7,12,13-tetrahydro-5,7-dioxo-indolo[2,3-a]furano[3,4-c]carbazole is obtained as a brownish amorphous powder. The 12-(2-carbamoylethyl)-6,7,12,13-tetrahydro-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]-carbazole used as starting material is prepared as follows: 500 mg (1.47 mmol) 6,7,12,13-tetrahydro-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole in 50 ml acetonitrile are stirred for 4 days at 20° C. with 1.05 g (14.8 mmol) acrylamide and 0.1 ml DBU. The suspension is evaporated, stirred with 30 ml dichloromethane/methanol (95:5 v/v) and the undissolved crystals are filtered off. 12-(2-carbamoylethyl)-6,7,12,13-tetrahydro-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo-[3,4-c]carbazole is obtained in the form of yellow crystals. The 6,7,12,13-tetrahydro-6-methyl-5,1-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole used as starting material is prepared as follows: 1 g (2.93 mmol) 3,4-bis-(indol-3-yl)-N-methyl-maleic acid imide is boiled under reflux for 1 hour with 800 mg (3.52 mmol) DDQ and 560 mg (2.94 mmol) p-toluenesulphonic acid hydrate in 200 ml toluene. Two thirds of the solvent are distilled off and the precipitate is filtered off and stirred with 100 ml 0.1N sodium hydroxide solution. It is filtered, the precipitate is washed with water, then suspended in ethanol and again filtered off. 6,7,12,13-Tetrahydro-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole is obtained in the form of a yellow amorphous powder; m.p. >350° C. The 3,4-bis-(indol-3-yl)-N-methylmaleic acid imide used as starting material is prepared in the manner described in the literature (see Tetrahedron, 1988, 44, 2887).

Workup

  1. customis prepared
  2. distillationTwo thirds of the solvent are distilled off
  3. filtrationthe precipitate is filtered off
  4. filtrationIt is filtered
  5. washthe precipitate is washed with water
  6. filtrationagain filtered off

Sources & evidence

ORD record
ord-374bdd4ef39b4e3fa70238ae12294823
Source dataset
uspto-grants-1999_03
Patent number
US05883114

Reaction notes

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