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

HRID 1840491Notes

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

Conditions

Temperature: 95 °C

Procedure

A mixture of 5-carboxy-2-oxindole (88.5 mg) (prepared as described in Compound IN-05), indole-2-carbaldehyde (87 mg) (prepared according to Synthetic Communications, 1993, 23, 3109) and piperidine (1 drop) in ethanol (3 mL) was heated 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 darker solid was collected by vacuum filtration, washed with cold ethanol and dried in vacuum oven for overnight 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

temperatureThe mixture was cooled to room temperature
filtrationThe solid was filtered
filtrationThe resulting darker solid was collected by vacuum filtration
washwashed with cold ethanol
customdried in vacuum oven for overnight

Sources & evidence

ORD record: ord-c97db97c0d9b49a784ee8ca5880e5230
Source dataset: uspto-grants-2004_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06680335B2

Reaction notes

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