Lithium hydroxide, monohydrate → 2-Methyl-1-(quinolin-4-yl)-1H-pyrrole-3-carboxylic acid

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Reaction Steps

2.226 g (53 mmol) of lithium hydroxide monohydrate, in portions of 0.742 g every 24 hours, are added at 20° C. to 2.48 g (8.4 mmol) of 3-ethoxycarbonyl-2-methyl-1-(quinol-4-yl)-1H-pyrrole dissolved in 75 mL of tetrahydrofuran and 75 mL of water. After stirring at reflux for 72 hours, the reaction mixture is concentrated to dryness under reduced pressure (2.7 kPa) to give a residue which is taken up in 40 mL of water and then triturated with 10 mL of 5N hydrochloric acid for 0.2 hour. After filtering off and drying the solid residue under reduced pressure (2.7 kPa) at 40° C., 2.09 g of 3-carboxy-2-methyl-1-(quinol-4-yl)-1H-pyrrole are obtained in the form of a pinkish solid. Mass spectrum (EI): m/e 252 (M+.), m/e 207.

Provenance & Evidence