The present disclosure relates to compounds of Formula I, its stereoisomers, pharmaceutically acceptable salts, complexes, hydrates, solvates, tautomers, polymorphs, racemic mixtures, optically active forms thereof and pharmaceutical compositions containing them as the active ingredient which can be used as medicaments. The aforementioned substances can also be used in the manufacture of medicaments for treatment, prevention or suppression of diseases, and conditions mediated by microbes. The present disclosure also relates to the synthesis.and characterization of aforementioned substances.