Diethyl Ether → ethyl 7-hydroxy-4-oxo-4H-chromen-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 2,4-dihydroxyacetophenone (15.2 g) in diethyloxalate (40 ml) is added with stirring to a solution of sodium (9.2 g) in ethanol (200 ml). The mixture is then heated at 100° C. for 3.5 hours, cooled and is added to dry ether (500 ml). The mixture is allowed to sit overnight. The resulting precipitate is filtered off and dissolved in water, and the solution is neutralized with 4N hydrochloric acid and extracted with ether. The ether extracts are combined and are concentrated down in vacuo. The resulting residue is dissolved in ethanol (100 ml) and concentrated hydrochloric acid is then added (2 ml). The solution is heated under reflux for 2 hours and is then concentrated in vacuo. The resulting solid is recrystalized in ethanol to give 2-carboethoxy-7-hydroxy-4-oxo-4H-1-benzopyran which is used directly in the next step.

Provenance & Evidence