Abstract 3-Amino-4H-1-benzothiopyran-4-one (3-aminothiochromone) was easily prepared by reaction of 3-bromo-thiochromen-4-one with sodium azide in methanol-water. Condensation of 3-aminothiochromone with diethyl ethoxymethylenemalonate and with dimethyl acetylenedicarboxylate gave intermediates, which were thermally cyclized to give 4, 10-dihydro-4, 10-dioxo-1H [1] benzothiopyrano [3, 2-b] pyridinecarboxylates. 3-Formyl- ...