Oxindole → 4-(2-Methoxycarbonyl-ethyl)-3-methyl-5-(2-oxo-1,2-dihydro-indol-3-ylidenemethyl)-1H-pyrrole-2-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

5-Formyl-4-(2-methoxycarbonylethyl)-3-methyl-1H-pyrrole-2-carboxylic acid ethyl ester (80.2 g), 2-oxindole (37.9 g) and ethanol (300 mL) were warmed to 70° C. in a 500 mL, 3-neck round bottom flask equipped with mechanical stirring and a reflux condenser. Piperidine (1.3 g) was added and the mixture was refluxed for 4 hours. The mixture was cooled to 10° C. and the orange precipitate collected by vacuum filtration and washed with 30 mL of ethanol. The solid was slurry-washed in 150 mL of refluxing ethanol, cooled, collected by vacuum filtration, washed with 30 mL of ethanol and vacuum dried to give 81.7 g (75%) of 4-(2-Methoxycarbonylethyl)-3-methyl-5-(2-oxo-1,2-dihydroindol-3-ylidenemethyl)-1H-pyrrole-2-carboxylic acid ethyl ester as an orange solid.

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