Synthesis and antibacterial activity of novel cinnoline-isoxazole derivatives

Abstract

Abstract A series of new bioactive cinnoline/ Isoxazole hybrid heterocyclics (7a-p) have been designed and synthesized from cinnoline by applying the regioselective nitrile oxide[1,3]-dipolar cycloadditions. All the synthesised compoundswere screened for their in vitro antibacterial activity. The results of screening revealed that compounds 7f, 7g, 7k, 7l, and 7o are potent antibacterial agents against the Gram- positive bacterial species Bacillus subtilis and Staphylococcus aureus as well as Gram- negative bacterial species Pseudomonas aeruginosa and Escherichia coli. When compared with the standard drug norfloxacin, compound 7k showed more potent antibacterial activity against the all Gram-positive and Gram-negative strains of bacteria. To understand the binding interactions of the most derivatives 7f, 7g, 7k, 7l and 7k molecular docking studies were performed with elastase of Pseudomonas aeruginosa (PDB: 1U4G ). These docking results revealed that this class of compounds have potential antibacterial activity.