Synthesis and Theoretical Studies of Biologically Active Thieno Nucleus Incorporated Tri and Tetracyclic Nitrogen Containing Heterocyclics Scaffolds via Suzuki Cross-Coupling Reaction.

A new series of thieno nucleus embellished trinuclear (19, 20) and tetranuclear (21-24) nitrogen heteroaryl have been synthesized by the Suzuki cross-coupling reaction using bis(triphenylphosphine)palladium(II) dichloride. All the synthesized compounds were characterized by IR, 1 H-NMR, 13 CNMR and Mass spectral properties. In vitro antibacterial studies of the synthesized compound were conducted using broth microdilution assay employing Gram-positive and Gram-negative strains and half-maximal inhibitory concentration (IC50 ) was determined. The result showed that compound 20 possess best antibacterial activity against S. aureus and E. coli with IC50 values of 60 µg mL-1 and 90 µg mL-1 . Further to determine the mode of antibacterial action, compounds 20 and 21 were examined for in vitro bacterial dehydrogenase inhibitory assay. To understand the binding affinity of the synthesized compounds, the docking study was performed in the bacterial dehydrogenase enzyme by AutoDock Vina software and structure was confirmed by Discovery Studio Visualizer. All the synthesized compounds were docked in a good manner within the active sites of the bacterial dehydrogenase enzyme and exhibited good binding energies.

Application of Palladium-Catalyzed Cross-Coupling Reactions in Organic Synthesis.

Palladium-catalyzed cross-coupling reactions have gained a continuously growing interest of synthetic organic chemists. The present review gives a brief account of applications of the palladium-catalyzed cross-coupling reactions in comprehensive synthesis, viz., the Heck, Stille, Suzuki-Miyaura, Negishi, Sonogashira, Buchwald-Hartwig, Ullmann and the Oxidative, decarboxylative cross-coupling reactions, with particular emphasis on the synthesis of heterocyclic compounds.