Synthesis Of New Chalcone Derivatives Containing Heterocyclic Moiety With Potential Antibacterial Activity

Infectious diseases are responsible for great number of deaths in the world population. The reduction of sensibility to antimicrobial agents in current use has been increasing for a great variety of pathogens and the resistance to multiple drugs is common for several microorganisms, especially for Gram positive bacteria. Infection by methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) presents a difficult problem for medicine. In addition, the treatment of infectious diseases is more complicated in immuno-suppressed patients, such as those infected with the HIV, undergoing anticancer therapy or transplants. Given the evidence for the rapid global spread of resistant clinical isolates and the appearance of drug-resistant strains among community acquired infections, the need for discovery or optimization of antimicrobial agents active against these resistant strains is of paramount importance.With an intention to synergise the antibacterial activity of chalcones and heterocyclic, several hybrid compounds possessing both chalcone and heterocyclic moieties were synthesized and tested for their antibacterial activity. The results demonstrated that some compounds presented great antimicrobial activities against Gram positive bacteria, including the multidrug-resistant clinical isolates. This class of compounds presented high potency against S. aureus, among which the derivatives 6k with MIC of 2μg/mL was as active as the standard drug, norfloxacin, less active than oxacillin. Compounds 6a-s and 8a-o did not inhibit the growth of Gram-negative bacteria Escherichia coli CCARM 1924 or Escherichia coli CCARM 1356 at 64μg/mL. The compounds synthesized were characterized by IR,1-NMR, MS.