Crystal structures and biological activity of homologated (N)-n-alkylammonium salts of 2-bromo-3-oxido-1,4-naphthoquinone

Homologated (N)- n -alkylammonium salts of 2-bromo-3-oxido-1,4-naphthoquinone (BS-1 to BS-8) have been synthesized and characterized from the single crystal X-ray diffraction experiments combined with density functional theory. The crystal structures revealed diverse noncovalent interactions such as hydrogen bonding, π∙∙∙π, Br∙∙∙π, and others. The measured antifungal activities of the BS-1 to BS-6 against fungal strains Saccharomyces cerevisiae and Candida albicans suggest them to be effective compared to standard drug amphotericin B. Antibacterial activity of BS-1 to BS-6 has been evaluated against Gram-positive and Gram-negative bacteria.