Hydrochloric Acid → 4-Methyl-2H-furo[3,2-b]indole-3(4H)-one

Participants

Reaction Steps

A mixture of 47.0 g (0.18 mole) of 3-hydroxy-4-methyl-4H-furo[3,2-b]indole-2-carboxylic ethyl ester (Prep. described in U.S. Pat. Application Serial Number 369,448) in 450 ml of 95% ethanol was treated with 450 ml of 30% aqueous sodium hydroxide. The mixture was stirred at reflux for two hours, cooled, added to 3.0 kg ice/water, and acidified with 6.0 N hydrochloric acid. The product was filtered, washed with water, and recrystallized from ethanol-water to yield 17.9 g (53% yield) of the product, mp 113°-116° C. An additional recrystallization as above raised the mp to 115.5°-118° C.

Provenance & Evidence