Synthesis of Naphtho[2,3‐ <i>b</i> ][1,10]phenanthrolines and Benzo[6,7]chromeno[3,2‐ <i>f</i> ]quinolines: One‐Pot Three‐Component Reaction of 2‐Hydroxy‐1,4‐Naphthoquinone, Aryl Aldehydes, and 8‐Aminoquinoline or 6‐Hydroxyquinoline

ABSTRACT In this work, we report new fused phenanthroline‐naphthoquinone and pyranoquinoline‐naphthoquinone for the synthesis of naphtho[2,3‐ b ][1,10]phenanthrolines and benzo[6,7]chromeno[3,2‐ f ]quinolines respectively. The one‐pot three‐component condensation of 2‐hydroxy‐1,4‐naphthoquinone, aryl aldehydes, and 8‐aminoquinoline or 6‐hydroxyquinoline is used for the synthesis of these two polycyclic heterocyclic ring systems. Formation of products proceeds through tandem Knoevenagel and Michael reactions, followed by concomitant cyclization and dehydration. Availability of the starting materials, operational simplicity, cleaner reaction profile, and the isolated products in pure form are the advantages of this protocol. The structure of all the products was characterized by spectroscopic techniques such as 1 H and 13 C NMR, IR spectral, and elemental analysis data.