Design,synthesis and bioevaluation of N-hydroxyquinolinones as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents

OBJECTIVE To establish a small compound library via a versatile synthetic route for the investigation of natural-inspiring compounds containing N-hydroxypyridones motif as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents.METHODS An amidation/cyclization approach was adopted to synthesize a library of N-hydroxyquinolinones.The anti-plasmodial susceptibility of lab clone 3D7 P.falciparum was measured using aprotocol modified from the WHO microtest.The minimum bactericidal concentration(MBC)values were determined against Escherichia coli and Staphylococcus arueus.Nine compounds were selected to test their iron(Ⅱ)-chelating abilities.The iron(Ⅱ)-chelating ability was determined by measuring the absorbance of ferrozine-iron complex at 562 nm.RESULTS A new route for the facile synthesis of a library of N-hydroxyquinolinones based on one-pot palladium catalyzed C-N amidation/dehydrocyclizationsequence was implemented.Four compounds show anti-plasmodial activities with the range of 1.1-1.4μmol·L-1,50% chelation abilities of the nine selected compounds were shown to be 0.24-0.29mmol·L-1.CONCLUSION Alibrary of N-hydroxyquinolinones was synthesized via a novel synthetic route.The anti-plasmodial and anti-bacterial activities of these compounds were evaluated.Four compounds show potent anti-plasmodial activities Nine compounds were examined for their propensities to undergo iron chelation and these compounds were shown to be promising iron(Ⅱ)chelators as compared to EDTA.