Water → HCID 15581187, compound

Participants

Reaction Steps

4.8 g of ethyl 5(5H-[1]benzopyrano[2,3-b]pyridin-7-yl)-5-cyano-4-oxovalerate is dissolved in 10 ml of concentrated hydrochloric acid. 30 ml of water is added at a stretch to the solution with stirring under ice-cooling, and the mixture is stirred under reflux for 5 hours. The reaction mixture is ice-cooled and adjusted to approximately pH 3 by addition of 30% sodium hydroxide. The resulting oil layer is extracted with chloroform, and the extract is dried over anhydrous sodium sulfate and concentrated. The oily residue, on standing, becomes solid. The solid is recrystallized from a mixture of dioxane and water (1:1) to give 3.4 g of 5-(5H-[1]benzopyrano[2,3-b]pyridin-7-yl)-4-oxovaleric acid as white needles melting at 146°-147°C.

Provenance & Evidence