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Journal of Chemistry
Volume 2013, Article ID 436758, 13 pages
http://dx.doi.org/10.1155/2013/436758
Research Article

Synthesis and Evaluation of Novel Fluorinated 2-Styrylchromones as Antibacterial Agents

1School of Chemistry, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
2School of Chemical Engineering, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
3Department of Biochemistry, Genetics, and Microbiology, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa

Received 27 May 2013; Revised 8 August 2013; Accepted 16 August 2013

Academic Editor: Hugo Verli

Copyright © 2013 Mehbub Momin 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

A range of fluorinated 2-styrylchromones (5a–g) of which six were new (5a–f) were prepared in three steps using the Baker-Venkataraman rearrangement along with two methoxylated derivatives (5h-i) and a methylenedioxy derivative (5j) and screened for their antibacterial activity using Gram-positive bacteria (Staphylococcus aureus, sciuri, and xylosus as well as Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia). The compounds were most effective against B. subtilis followed by S. aureus and a single strain of E. coli (ATCC 25922). Difluorination on the phenyl ring was shown to enhance antibacterial activity, and fluorine substitution at the 6 position was shown to be far superior to substitution at the 7 position. In comparison to tetracycline, the activity indices of the fluorinated styrylchromones ranged from 0.50 to 0.75 against B. subtilis. The crystal structure of 2′-fluoro-2-styrylchromone is also presented, and the molecule was shown to be planar.