Potassium Hydroxide → 4-(2-carboxyethyl)-3-methyl-5-(4-methyl-2-oxo-1,2-dihydroindol-3-ylidenemethyl)-1H-pyrrole-2-carboxylic acid

HRID 24540Notes

Reaction equation

C([O:3][C:4]([C:6]1[NH:7][C:8]([CH:19]=O)=[C:9]([CH2:12][CH2:13][C:14]([O:16]CC)=[O:15])[C:10]=1[CH3:11])=[O:5])C.[CH3:21][C:22]1[CH:30]=[CH:29][CH:28]=[C:27]2[C:23]=1[CH2:24][C:25](=[O:31])[NH:26]2.[OH-].[K+]>N1CCCCC1.C(O)C>[C:14]([CH2:13][CH2:12][C:9]1[C:10]([CH3:11])=[C:6]([C:4]([OH:3])=[O:5])[NH:7][C:8]=1[CH:19]=[C:24]1[C:23]2[C:27](=[CH:28][CH:29]=[CH:30][C:22]=2[CH3:21])[NH:26][C:25]1=[O:31])([OH:16])=[O:15]

Participants

Conditions

Temperature: 90 °C

Procedure

A mixture of 5-formyl-4-(2-ethoxycarbonylethyl)-3-methyl-1H-pyrrole-2-carboxylic acid ethyl ester (281 mg), 4-methyl-2-oxindole (147 mg) and piperidine (2 drops) in ethanol (2 mL) was stirred at 90° C. for 2 hours. Potassium hydroxide (213 mg) was added, the temperature was increased to 95° C. and held there for 1 hour. The reaction mixture was cooled and concentrated. The residue was dissolved into water and acidified with 2 N hydrochloric acid to pH 2. The precipitate was filtered, washed with water and dried in a vacuum oven overnight to give 337 mg (95%) of 4-(2-carboxyethyl)-3-methyl-5-(4-methyl-2-oxo-1,2-dihydroindol-3-ylidenemethyl)-1H-pyrrole-2-carboxylic acid.

Workup

temperaturethe temperature was increased to 95° C.
waitheld there for 1 hour
temperatureThe reaction mixture was cooled
concentrationconcentrated
dissolutionThe residue was dissolved into water
filtrationThe precipitate was filtered
washwashed with water
customdried in a vacuum oven overnight

Sources & evidence

ORD record: ord-bc13020b104d40ce800ed3388ae178bc
Source dataset: uspto-grants-2005_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06855730B2

Reaction notes

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