Abstract
A series of bichalcophene monoamidines 4a-f were synthesized from the corresponding mononitriles 3a-f via a direct reaction with LiN(TMS)(2) followed by deprotection with ethanolic HCl (gas). Bichalcophene mononitriles 3a-f were synthesized via palladium-catalyzed coupling reactions. Thus, a Stille coupling reaction was performed to prepare 6-[5-(thiophen-2-yl)furan-2-yl]nicotinonitrile (3e), when 6-(5-bromofuran-2-yl)nicotinonitrile was allowed to react with 2-n-tributyltin thiophene. The tested bichalcophenes showed a wide range of DNA and protein degradation effect as judged from agarose gel and SDS-PAGE, respectively. Bichalcophenes 3a-f and 4a-f have broad-spectrum antibacterial efficacy being highly active against both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, and Escherichia coli) bacterial strains. The antifungal activity of these bichalcophene series against Saccharomyces cerevisiae was demonstrated. The MIC of bichalcophenes 3a-f and 4a-f against various microorganisms was also determined. The tested bichalcophenes mimic SOD like activity and inhibited the superoxide radical generation.