Synthesis of 4,10-dihydro-4,10-dioxo-1H-[1]-benzopyrano[3,2-b]pyridine, 4,5-Dihydro-4,5-dioxo-1H-[1]-benzopyrano[2,3–6]pyridine and 1,5-Dihydro-1,5-dioxo-4H-[1]-benzopyrano[3,4-b]pyridine derivatives from aminobenzopyrones

3-Aminochromone and 3-aminocoumarin were condensed with diethyl ethoxymethylenemalonate and with dimethyl acetylenedicarboxylate to give intermediates, which were thermally cyclized to give 4,10-dihydro-4,10-dioxo-lH-1]-benzopyrano3,2-b]pyridinecarboxylates and 1,5-dihydro-1,5-dioxo-4H-1]-benzopyrano-3,4-b]pyridinecarboxylates. 2-Aminochromone was converted to 4,5-dihydro-4,5-dioxo-1H-1]-benzopyrano-2,3-b]pyridinecarboxylate via an intermediate condensation product with diethyl ethoxymethylenemalonate. These esters were hydrolyzed to the corresponding carboxylic acids (21, 30, 36, 50, and 60). Attempts to prepare 4,5-dihydro-4,5-dioxo-1H-1]-benzopyrano4,3-b]pyridinecarboxylates from 4-aminocoumarin were unsuccessful.