Hydrochloric Acid → 3-{2-[6-(3-ethoxyphenyl)-2-oxo-1,2-dihydroindol-3-ylidenemethyl]-4-methyl-1H-pyrrol-3-yl}-propionic acid

Participants

Reaction Conditions

Reaction Steps

4-(2-Carboxyethyl)-5-[6-(3-ethoxyphenyl)-2-oxo-1,2-dihydroindol-3-ylidenemethyl]-3-methyl-1H-pyrrole-2-carboxylic acid (350 mg) suspended in ethylene glycol (5 mL) was held in a sealed tube in a pre-heated oil bath at 200° C. for 2.5 hours. The reaction mixture was cooled to 100° C. and potassium hydroxide (4 pellets) was added. It was then stirred at 100° C. for 2 hours. The reaction mixture was cooled, poured 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. The crude solid was purified on a silica gel column using 33:66:1 ethyl acetate:hexanes:glacial acetic acid to give 140 mg (44%) of 3-{2-[6-(3-ethoxyphenyl)-2-oxo-1,2-dihydroindol-3-ylidenemethyl]-4-methyl-1H-pyrrol-3-yl}-propionic acid as a brown solid.

Provenance & Evidence