6-(3-Ethoxyphenyl)indolin-2-one → 4-(2-Carboxyethyl)-5-[6-(3-ethoxyphenyl)-2-oxo-1,2-dihydroindol-3-ylidenemethyl]-3-methyl-1H-pyrrole-2-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 5-formyl-4-(2-ethoxycarbonylethyl)-3-methyl-1H-pyrrole-2-carboxylic acid ethyl ester (281 mg), 6-(3-ethoxyphenyl)-2-oxindole (304 mg), and piperidine (2 drops) in ethanol (5 mL) were held at 90° C. overnight. The precipitate that formed was filtered, washed with ethanol. The precipitate, an orange solid, was stirred with potassium hydroxide (4 pellets) in ethanol (3 mL) at 90° C. for 2.5 hours. The reaction mixture was cooled and concentrated. The residue was dissolved into water and acidified with 2N hydrochloric acid to pH 2. The precipitate was filtered, washed with water, and dried in a vacuum oven overnight to give 370 mg of 4-(2-Carboxyethyl)-5-[6-(3-ethoxyphenyl)-2-oxo-1,2-dihydroindol-3-ylidenemethyl]-3-methyl-1H-pyrrole-2-carboxylic acid.

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