Indole-2-carboxaldehyde → 3-(1H-indol-2-ylmethylene)-2-oxo-2,3-dihydro-1H-indole-5-carboxylic acid

HRID 1860888Notes

Reaction equation

HRID 1860888 reaction equation
[C:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][C:8](=[O:13])[CH2:7]2)([OH:3])=[O:2].[NH:14]1[C:22]2[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=2)[CH:16]=[C:15]1[CH:23]=O>N1CCCCC1.C(O)C>[NH:14]1[C:22]2[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=2)[CH:16]=[C:15]1[CH:23]=[C:7]1[C:6]2[C:10](=[CH:11][CH:12]=[C:4]([C:1]([OH:3])=[O:2])[CH:5]=2)[NH:9][C:8]1=[O:13]

Participants

5

Reactant 2

HCID 96389Indole-2-carboxaldehydeHCID 27733182-Oxindole-5-carboxylic acid

Product 1

HCID 540903703-(1H-indol-2-ylmethylene)-2-oxo-2,3-dihydro-1H-indole-5-carboxylic acidYield 40%

Reagents, catalysts & solvents 2

HCID 8082PiperidineCatalystHCID 702EthanolSolvent

Procedure

A mixture of 5-carboxy-2-oxindole (88.5 mg), indole-2-carbaldehyde (87 mg) (prepared according to Synthetic Communications, 1993, 23, 3109) and piperidine (1 drop) in ethanol (3 mL) was held in a sealed tube at 95° C. for 4 hours. The mixture was cooled to room temperature. The solid was filtered and acidified with 2N hydrochloric acid. The resulting solid was collected by vacuum filtration, washed with cold ethanol and dried in vacuum oven to give 60 mg (40% yield) of 3-(1H-indol-2-ylmethylene)-2-oxo-2,3-dihydro-1H-indole-5-carboxylic acid as a mustard-colored solid.

Workup

  1. filtrationThe solid was filtered
  2. filtrationThe resulting solid was collected by vacuum filtration
  3. washwashed with cold ethanol
  4. customdried in vacuum oven

Sources & evidence

ORD record
ord-ad8c008e539f487b9db8a5f30890f3eb
Source dataset
uspto-grants-2003_03
Patent number
US06531502B1

Reaction notes

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