Title:
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Design and synthesis of potential antimicrobial agents
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A series of pyridine-2-, pyridine-3-, pyridine-4-, pyrazine and quinoline-2-carboxamidrazone derivatives and new classes of carboxamidrazone were prepared. Over nine hundred synthesized compounds were screened for their antimycobacterial activity against M. fortutium (NCTC 10394) as a surrogate for M. tuberculosis. The new classes of amidrazones were also screened against tuberculosis H37 Rv. Fifteen tested compounds were found to provide 90-100% inhibition of mycobacterium growth of M. tuberculosis H37 Rv in the primary screen at 6.25 μg mL-1. The most active compound in the carboxamidrazone amide series had an MIC value of 0.1-2 μg mL-1 against M. fortutium. The x-ray structure of DHFR from M. tuberculosis and human DHFR were found to have differences in substrate binding site. The presence of glycerol molecule in the X-ray structure from M. tuberculosis DHFR provided opportunity to design new antifolates. The new antifolates were designed to retain the pharmocophore of pyrimethamine (2,4-diamino-5(4-chlorophenyl)-6-ethylpyrimidine), but encompassing a range of polar groups that might interact with the M. tuberculosis DHFR glycerol binding pockets. Finally, the research describes the preparation of molecularly imprinted polymers for the recognition of 2,4-diaminopyrimidine for the binding of the target. Having proven that 2,4-diaminopyrimidine interacts strongly with the model 5-(4-tert-butyl-benzylidene)-pyrimidine-2,4,6-trione, 2,4-diaminopyrimidine-imprinted polymers were prepared using a novel cyclobarbital derived functional monomer, acrylic acid 4-(2,4,6-trioxo-tetrahydro-pyrimidin-5-ylidenemethyl)phenyl ester, capable of multiple hydrogen bond formation with the 2,4-diaminopyrimidine. The recognition property of the respective polymers toward the templates and other test compounds was evaluated. The polymers showed dose dependent enhancement of fluorescence emissions. Synthesized MIPs have higher 2,4-diaminopyrimidine binding ability as compared with corresponding non-imprinting polymers.
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