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Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents. An investigation into the synthesis of substituted benzimidazoles and their evaluation in vitro for antimicrobial activity.

Microbe resistence is a serious issue, especially as they have become resistant to
most well known drugs. Therefore this is considered as a global problem and is now
dealt with at a poitical level. Since no new classes of antimicrobial agents have
been discovered in the past three deacdes, the development of new drugs is
extremely urgent. Therefore the aim of this project was to synthesise derivatives of
benzimidazole, and then assesses their antimicrobial activities in vitro by using disc
(well) diffusion and MICs tests.
A total of 69 benzimidazole derivatives, with substituents at positions 1, 2, and 5,
were synthesised, characterised and tested against selected bacteria and fungi. In
addition, six bezimidazole silver complexes were prepared and evaluated for their
antimicrobial behavior.
The SAR showed that the antimicrobial activity of the compounds depended on the
substituents attached to the bicyclic heterocycle. Some promising results were
obtained. In particular, 5 compounds displayed antibacterial activity against two
MRSA strains with MIC values corresponding to ciprofloxacin, which can be
considered significant. The compounds have some common features; four possess
5-chloro or 5-bromo substituents; two are derivatives of (S)-2-
ethanaminebenzimidazole and the others are derivative of one 2-(chloromethyl)-1Hbenzo[d]imidazole, (1H-benzo[d]imidazol-2-yl)methanethiol and 2-(methoxymethyl)-1-methyl-1H-benzo[d]imidazole.
The results from the antifungal screening were very interesting as there were 26
compounds, including two silver complexes, which were potent fungicides against
the selected fungal species. They showed equivalent or greater potentency in their
MIC values than amphotericin B. In particular, the 5-fluoro, 5-chloro and 5-bromo
benzimidazole showed broad spectrum activity. / Saudi Culture Bureau and King Saud University

Identiferoai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/6325
Date January 2013
CreatorsAlasmary, Fatmah A.S.
ContributorsKarodia, Nazira, Snelling, Anna M.
PublisherUniversity of Bradford, School of Pharmacy
Source SetsBradford Scholars
LanguageEnglish
Detected LanguageEnglish
TypeThesis, doctoral, PhD
Rights<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>.

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