Palladium-catalyzed arylation of 2H-chromene: a new entry to pyrano[2,3-c]carbazoles

Pyrano[2,3-c]carbazoles which are biologically valuable and synthetically challenging frameworks are synthesized in high yields over five steps from commercially available resorcinol. Palladium-catalyzed arylation remains a key step in this novel strategy. The versatility of this protocol has been demonstrated by the synthesis of naturally occurring alkaloid clauraila C and 7-methoxyglycomaurin. The anti-proliferative activity of these designed compounds (5a, 5f, and 5l) has been evaluated in a cancer cell line (MOLT-4). The molecular docking study revealed that this pyrano[2,3-c]carbazole class of molecules selectively occupies the colchicine binding site of the tubulin-polymer.