3,4-Dichlorophenol → beta-Carbolin-3-carboxylic acid 3,4-dichlorophenyl ester

HRID 1757988Notes

Reaction equation

HRID 1757988 reaction equation
[CH:1]1[C:13]2[NH:12][C:11]3[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=3)[C:5]=2[CH:4]=[C:3]([C:14]([OH:16])=[O:15])[N:2]=1.ClC(OCC)=O.[Cl:23][C:24]1[CH:25]=[C:26](O)[CH:27]=[CH:28][C:29]=1[Cl:30].[H-].[Na+].C1([O-])C=CC=CC=1>O1CCCC1.C(N(CC)CC)C>[Cl:23][C:24]1[CH:25]=[C:26]([O:15][C:14]([C:3]2[N:2]=[CH:1][C:13]3[NH:12][C:11]4[C:6]([C:5]=3[CH:4]=2)=[CH:7][CH:8]=[CH:9][CH:10]=4)=[O:16])[CH:27]=[CH:28][C:29]=1[Cl:30]

Participants

8

Reactant 5

HCID 72583,4-DichlorophenolHCID 10928Ethyl chloroformateHCID 24758Sodium hydrideHCID 119047PhenolateHCID 1732629H-Pyrido(3,4-b)indole-3-carboxylic acid

Product 1

HCID 54441906beta-Carbolin-3-carboxylic acid 3,4-dichlorophenyl ester

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent4×HCID 8471TriethylamineSolvent

Procedure

A suspension of 2.5 g of β-carbolin-3-carboxylic acid in a mixture of 450 ml of dry tetrahydrofuran and 1.8 ml of triethylamine is boiled under reflux for 15 minutes and cooled to room temperature. Freshly distilled ethyl chloroformate (1.25 ml) dissolved in 50 ml of dry tetrahydrofuran is added dropwise with stirring over a period of 1 hour. The reaction mixture (1) is stirred for additionally 30 minutes. A solution of 1.9 g of 3,4-dichlorophenol in 25 ml of dry tetrahydrofuran is added to 0.5 g of a 55% sodium hydride dispersion in oil suspended in 75 ml of dry tetrahydrofuran. The solution of the phenolate is added to mixture (1). Stirring is continued for one hour, whereafter the reaction mixture is filtered and concentrated to approximately 50 ml in vacuo. Addition of water (250 ml) causes the ester to precipitate. The mixture is left at 5° C. overnight and filtered. The dry product (3.0 g; 71%) is recrystallized from xylene to give pure β-carbolin-3-carboxylic acid 3,4-dichlorophenyl ester which melts at 260°-261° C.

Workup

  1. temperatureunder reflux for 15 minutes
  2. additionis added dropwise
  3. stirringStirring
  4. waitis continued for one hour, whereafter the reaction mixture
  5. filtrationis filtered
  6. concentrationconcentrated to approximately 50 ml in vacuo
  7. additionAddition of water (250 ml)
  8. customto precipitate
  9. waitThe mixture is left at 5° C. overnight
  10. filtrationfiltered
  11. customThe dry product (3.0 g; 71%) is recrystallized from xylene

Sources & evidence

ORD record
ord-f818ead4a846455ba4c933bb454209f7
Source dataset
uspto-grants-1983_02
Patent number
US04371536

Reaction notes

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