Methyl iodide → 6,7,12,13-Tetrahydro-3,9-dimethoxy-6,12-dimethyl-5,7-dioxo-5H-indolo[2,3-a]-pyrrolo[3,4-c]carbazole

HRID 1418637Notes

Reaction equation

HRID 1418637 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]2[NH:9][C:10]3[C:22]4[N:21]([CH3:23])[C:20]5[C:15](=[CH:16][C:17]([O:24][CH3:25])=[CH:18][CH:19]=5)[C:14]=4[C:13]4[C:26](=[O:30])[NH:27][C:28](=[O:29])[C:12]=4[C:11]=3[C:5]=2[CH:4]=1.[CH3:31]OC1CC(=O)C2NC3C4N(C)C5C(=CC(OC)=CC=5)C=4C4CN(C)C(=O)C=4C=3C=2C=1.COC1C=CC2NC3C4NC5C(=CC(OC)=CC=5)C=4C4C(=O)N(C)C(=O)C=4C=3C=2C=1.CI.S(OC)(OC)(=O)=O.[H-].[Na+]>CN(C)C=O>[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]2[NH:9][C:10]3[C:22]4[N:21]([CH3:23])[C:20]5[C:15](=[CH:16][C:17]([O:24][CH3:25])=[CH:18][CH:19]=5)[C:14]=4[C:13]4[C:26](=[O:30])[N:27]([CH3:31])[C:28](=[O:29])[C:12]=4[C:11]=3[C:5]=2[CH:4]=1

Participants

8

Reactant 6

HCID 6328Methyl iodide2×HCID 6497Dimethyl SulfateHCID 24758Sodium hydrideHCID 212168326,7,12,13-tetrahydro-3,9-dimethoxy-6-methyl-5,7-dioxo-5H-indolo[2,3-a]-pyrrolo[3,4-c]carbazole2×HCID 212168516,7,12,13-tetrahydro-3,9-dimethoxy-12-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazoleHCID 867539116,7,12,13-tetrahydro-3,9-dimethoxy-6,12-dimethyl-5,1-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]-carbazole

Product 1

HCID 212168616,7,12,13-Tetrahydro-3,9-dimethoxy-6,12-dimethyl-5,7-dioxo-5H-indolo[2,3-a]-pyrrolo[3,4-c]carbazole

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent2×

Conditions

Temperature
200 °C

Procedure

6,7,12,13-tetrahydro-3,9-dimethoxy-12-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole; yellow crystals; m.p. >330° C. The 6,7,12,13-tetrahydro-3,9-dimethoxy-6,12-dimethyl-5,1-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]-carbazole used as starting material is prepared by the methylation of 6,7,12,13-tetrahydro-3,9-dimethoxy-6-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]-carbazole (precursor for Example 7) with methyl iodide or dimethyl sulphate in the following manner: A solution of 1 g (2.5 mmol) 6,7,12,13-tetrahydro-3,9-dimethoxy-6-methyl-5,7-dioxo-5H-indolo[2,3-a]-pyrrolo[3,4-c]carbazole in 50 ml dry dimethylformamide is added dropwise at 20° C. to a suspension of 91 mg (3.0 mmol) sodium hydride (80% in paraffin oil) in 5 ml dimethylformamide under an atmosphere of argon. After stirring for 1 hour at 200° C., 0.2 ml (3.2 mmol) methyl iodide are added thereto and the reaction mixture is stirred for 16 hours at 20° C. It is then evaporated in a vacuum and the residue is partitioned between ethyl acetate and water. The ethyl acetate phase is separated off, dried over anhydrous sodium sulphate, filtered and evaporated. The residue is stirred with 30 ml diisopropyl ether/ethyl acetate (2:1 v/v) and the undissolved product is filtered off. 6,7,12,13-Tetrahydro-3,9-dimethoxy-6,12-dimethyl-5,7-dioxo-5H-indolo[2,3-a]-pyrrolo[3,4-c]carbazole is obtained in the form of a pale brown amorphous powder. The methylation can also be carried out in an analogous manner with dimethyl sulphate as alkylation agent.

Workup

  1. stirringthe reaction mixture is stirred for 16 hours at 20° C
  2. customIt is then evaporated in a vacuum
  3. customthe residue is partitioned between ethyl acetate and water
  4. customThe ethyl acetate phase is separated off
  5. dry with materialdried over anhydrous sodium sulphate
  6. filtrationfiltered
  7. customevaporated
  8. stirringThe residue is stirred with 30 ml diisopropyl ether/ethyl acetate (2:1 v/v)
  9. filtrationthe undissolved product is filtered off

Sources & evidence

ORD record
ord-a2e55918f46b4bd291c48e290755cbaf
Source dataset
uspto-grants-1999_03
Patent number
US05883114

Reaction notes

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