1548
M. A. Weidner-Wells et al. / Bioorg. Med. Chem. Lett. 11 (2001) 1545±1548
Several of the more potent analogues were tested for in
vitro antibacterial activity against important Gram-
positive pathogens (Table 6). The TCS inhibitory activ-
ity of the benzimidazoles generally correlated with
antibacterial activity within each subseries. In parti-
cular, there was a uniform 8-fold dierence in the MIC
values for the organisms studied between the regioiso-
meric mono-t-butyl compounds 11 and 12. This is con-
sistent with the IC50 values observed for these two
compounds. Benzimidazole 8 and benzoxazoles 21 and
23 displayed comparable antibacterial activity thus
indicating that the NH is not essential for activity.
However, for N-methyl analogue 19, a free NH may
contribute to antibacterial activity, since there is a 2- to
>4-fold decrease in the MIC values.
Acknowledgements
The authors wish to thank Dr. Jamese Hilliard for techni-
cal contributions and Drs. Karen Bush and Raul Gold-
schmidt for their critical assessment of the manuscript.
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8.11
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