Heterobicyclic oxazolo pyrimidinone are important class of compounds. They may become promising candidates for exploiting more useful therapeutically active molecules. The compounds having oxazolo pyrimidinone moiety are associated with interesting wide spectrum biological activities, such as antibacterial, kinase inhibition, adenosine receptor antagonism, tumour growth inhibition and some show to inhibit the ability of ricin to inactivate the ribosomes etc. The intermediate azlactones are also useful precursors for the synthesis of amino acids, peptides, heterocycles, biosensors and antitumor or antimicrobial compounds. In the present study, it was proposed to synthesize lead molecules of oxazolo pyrimidinone skeleton, apt for binding to the target enzyme, bacterial MurB based on the rational approach and to study their docking simulations using ArgusLab 4.0.1 and AutoDock 4.2 softwares. The synthesized test compounds were then characterized by TLC, melting point determination, UV, IR, 1H-NMR and mass spectral studies and tested for their antibacterial activity and compare with the standard drug.

Coumarins are important class of compounds, isomeric to quinolones. They may become promising candidates for exploiting more useful therapeutically active molecules. DNA-gyrase has drawn much attention as selected target for finding potent anti-bacterial agents against multi-drug resistant strains such as methicillin-resistant Staphyloccus aureus (MRSA), vancomycin-resistant enterococci (VRE), penicillin-resistant Streptococci pneumonia (PRSP). The objective of the present study was, to study the molecular docking simulations on 5,7-dihydroxy-4-methyl coumarin analogues as probable candidates for inhibiting DNA gyrase subunit-B of S.aureus. In the present study, Docking simulations were carried out on the reported inhibitors of DNA-gyrase subunit A and B using docking software. Based on it, Series of 5,7-dihydroxy-4-methylcoumarin analogues (PH-1 to PH-9) were designed, synthesized, characterized and evaluated for its anti-bacterial activity against S.aureus and E.coli. Out of the nine test compounds, compound PH-4 showed good anti-bacterial activity against S.aureus and E.coli than rest of other compounds.