Design, Characterization and Antimicrobial Efficiency of Novel Annulated Furo[3'',2'':6',7']Chromeno[3',4':4,5]Furo [3,2-b]Pyridines

The principle approach of the present study is directed to find an appropriate technique to create a new category of multi-fused compounds including furo[3,2-g]chromenes. The novel 2-acetyl-3-amino-6,10-dimethoxy-4-oxo-4H-difuro[3,2-c:3′,2′-g]chromene (3) was efficiently synthesized and utilized as a key intermediate to build a new class of multi-fused compounds namely furo[3′′,2′′:6′,7′]chromeno[3′,4′:4,5]furo[3,2-b]pyridines. Reaction of precursor 3 with active methylene nitriles yielded 2-amino-3-substituted furo[3′′,2′′:6′,7′]chromeno[3′,4′:4,5]furo[3,2-b]pyridines 4–9. Also, Friedländer's reaction of precursor 3 with active methylene ketones produced hetero-annulated furochromenofuropyridines 10–13. The synthesized compounds showed high inhibition action when tested in vitro against fungal strains, whereas compounds 3 and 8 showed good inhibitory effects against all types of tested microorganisms. The structures of the novel annulated compounds were inferred using spectral and analytical results.