Synthesis and reactions of pyranoquinolines

6-Aminocoumarins 1a-c are refluxed with ethyl benzoylacetate 2 in toluene to give benzoyl-N-(6'-coumarinyl)-acetamides 3a-c, which on cyclisation with PPA afforded pyranoquinolines 4a-c. These are further converted into chloropyranoquinolines 5a-c using PCl5 and POCl3. These chloro derivatives are further treated separately, with sodium a de, a thranilic acid, o-phenylenediamine and benzoic hydrazide to obtain novel heterocyclic compounds, 9H-9-oxo-6-phenyl[10]pyrano[3,2-f]quinoline[1',5':1,2] tetrazoles 6a-c, 10H,15H-10,15-dioxo-7-phenyl[11]pyrano[3,2-f]quinolino[1',2':1,2] quinozolines 7a-c, 10H-10-oxo-7-phenyl[11]pyrano[3,2-f]quinolino[1',2':1,2] benzimidazoles 8a-c and 9H-2,6-diphenyl-9- oxo[10]pyrano[3,2-f] quinolino[1',2:1,2]triazoles 9a-c, respectively.