Water → 3,7-Dimethoxy-4-phenyl-4H-furo[3,2-b]indole-2-carboxylic acid

HRID 2164334Notes

Reaction equation

HRID 2164334 reaction equation
C[O:2][C:3]([C:5]1[O:16][C:15]2[C:14]3[CH:13]=[C:12]([O:17][CH3:18])[CH:11]=[CH:10][C:9]=3[N:8]([C:19]3[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=3)[C:7]=2[C:6]=1[O:25][CH3:26])=[O:4].[OH-].[Na+].O.N1C2C(=CC=C3OC=CC3=2)C=C1>C(O)C.ClCCl>[CH3:26][O:25][C:6]1[C:7]2[N:8]([C:19]3[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=3)[C:9]3[CH:10]=[CH:11][C:12]([O:17][CH3:18])=[CH:13][C:14]=3[C:15]=2[O:16][C:5]=1[C:3]([OH:4])=[O:2]

Participants

7

Reactant 4

HCID 962WaterHCID 14798Sodium HydroxideHCID 13220388HCID 13220388, compoundHCID 451226001H-Furo[2,3-g]indole

Product 1

HCID 132203913,7-Dimethoxy-4-phenyl-4H-furo[3,2-b]indole-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 6344DichloromethaneSolvent

Procedure

A suspension of 11.5 g (0.033 mole) of 3,7-dimethoxy-4-phenyl-4H-furo[3,2-b]indole-2-carboxylic acid methyl ester in 200 ml of 50% aqueous ethanol was treated with 25 ml of 10% aqueous sodium hydroxide solution. After stirring at reflux for 90 minutes, the reaction mixture was cooled and distributed between 750 ml of water and 250 ml of dichloromethane. The insoluble material (primarily the sodium salt of the product) was removed by filtration. The filtrate layers were separated, and the organic layer was discarded. The aqueous layer was washed several times with fresh dichloromethane, cooled in ice, and acidified with 4N hydrochloric acid. The precipitate crude product was filtered and washed with water. The original insoluble sodium salt was stirred for several hours in 400 ml of cold 1N hydrochloric acid, and the product acid was filtered, washed with water, and combined with the material obtained from acidification of the original aqueous layer. The crude yield of the furoindole acid was 9.4 g (85%) yield). A sample recrystallized from acetone/water was analytically pure, mp 148° C. (dec).

Workup

  1. temperatureat reflux for 90 minutes
  2. temperaturethe reaction mixture was cooled
  3. customThe insoluble material (primarily the sodium salt of the product) was removed by filtration
  4. customThe filtrate layers were separated
  5. washThe aqueous layer was washed several times with fresh dichloromethane
  6. temperaturecooled in ice
  7. filtrationThe precipitate crude product was filtered
  8. washwashed with water
  9. stirringThe original insoluble sodium salt was stirred for several hours in 400 ml of cold 1N hydrochloric acid
  10. filtrationthe product acid was filtered
  11. washwashed with water
  12. customobtained from acidification of the original aqueous layer
  13. customyield)
  14. customA sample recrystallized from acetone/water

Sources & evidence

ORD record
ord-4583991c701f4880a5e0f7f5a2eabd97
Source dataset
uspto-grants-1985_03
Patent number
US04503236

Reaction notes

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