Acetic Acid → 3-Ethoxy-4-phenyl-4H-furo[3,2-b]indole-2-carboxylic acid

Participants

Reaction Steps

A suspension of 12.0 g (0.036 mole) of 3-ethoxy-4-phenyl-4H-furo[3,2-b]indole-2-carboxylic acid methyl ester in 100 ml of methanol was treated with 60 ml of 1.0 N aqueous sodium hydroxide. After stirring at reflux for 20 hours, the cooled reaction mixture was added to 1.2 kg ice/water, and the mixture was acidified with acetic acid. The crude product was filtered, stirred in 600 ml water, and refiltered. Recrystallization from ethanol yielded 5.1 g of analytically pure acid containing 0.35 mole of water of hydration, mp 146°-147° C. An additional 1.8 g of product was obtained from the recrystallization filtrate, for a total yield of 6.9 g (59% yield).

Provenance & Evidence