Hydrochloric Acid → 2,8-Diethyl 6,9-dihydro-4,6-dioxo-10-propyl-4H-pyrano[3,2-g]quinoline-2,8-dicarboxylate

Participants

Reaction Steps

Treatment of the product of step (e) (1 mmole) with sodium ethoxide (10 mmole), in ethanol (10 ml) containing diethyl oxalate (10 mmole) at reflux for 3 hours, followed by acidification of the mixture, which contained the sodium salt of diethyl 4,4'-(2-amino-4-hydroxy-3-propylphenylene-1,3-diyl)bis(2,4-dioxo-butanoate), with gaseous HCl and heating under reflux for 1 hour afforded the sub-title compound which was isolated by dilution with water, extraction with chloroform, concentration and purification by column chromatography (yield 65%) mp 211°-212°.

Provenance & Evidence