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International Journal of Medicinal Chemistry
Volume 2012, Article ID 782058, 6 pages
http://dx.doi.org/10.1155/2012/782058
Research Article

Syntheses and In Vitro Biological Activity of Some Derivatives of C-9154 Antibiotic

1School of Chemistry, University of Kwazulu-Natal, Durban-4000, South Africa
2Department of Chemistry, Ahmadu Bello University, Zaria-810001, Nigeria
3College of Agriculture, Division of Agricultural Colleges, Ahmadu Bello University, Zaria-810001, Nigeria
4Department of Chemistry, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa-3886, South Africa

Received 29 May 2012; Accepted 30 October 2012

Academic Editor: Armando Rossello

Copyright © 2012 Isaac Asusheyi Bello et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In our continued attempts at designing new antibiotics based on the structure of the C-9154 antibiotic, to simultaneously improve activity and lower toxicity, an analogue to the C-9154 antibiotic and six derivatives of this analogue were synthesized. The approach was to significantly reduce the polarity of the synthesized analogue in the derivatives to achieve increased permeability across cell membranes by conversion of the highly polar carboxylic group to an ester functional group. The compounds were synthesized using a two-step reaction which involved an additional reaction between benzyl amine and maleic anhydride and then conversion of the terminal carboxylic acid functional group to an ester functional group using a thionyl chloride mediated esterification reaction. The compounds were fully characterized using Infrared, GC-MS, and 1D and 2D NMR experiments. The in vitro biological activity of the compounds showed that the derivatives were more active than the analogues as was anticipated with minimum inhibitory concentration in the range 0.625–5 μg/mL. The analogue had minimum inhibitory concentration in the range 2.5–10 μg/mL. These values are significantly better than that obtained for the original C-9154 antibiotic which had activity in the range 10–>100 μg/mL.