Acetic Acid → 2-(5H-chromeno[2,3-b]pyridin-7-yl)acetic acid

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Reaction Steps

A solution of 11.5 g of 7-cyanomethyl-5H-[1]benzopyrano[2,3-b]-pyridine in a mixture of 60 ml of acetic acid and 25 ml of concentrated hydrochloric acid is heated under reflux for 24 hours. After concentration, water is added to the residue, and further 10% sodium hydroxide solution is added to dissolve the residue. An insoluble material is removed by extraction with chloroform. The aqueous layer is made acid with acetic acid, and the resulting crystalline precipitate is filtered off. The crystals are recrystallized from dioxane to give 8.5 g of 5H-[1]benzopyrano[2,3-b]-pyridin-7-yl-acetic acid as white needles melting at 218°C.

Provenance & Evidence