Synthesis, Absolute Configuration, Antibacterial, and Antifungal Activities of Novel Benzofuryl β-Amino Alcohols

A series of new benzofuryl alpha-azole ketones was synthesized and reduced by asymmetric transfer hydrogenation (ATH). Novel benzofuryl beta-amino alcohols bearing an imidazolyl and triazolyl substituents were obtained with excellent enantioselectivity (96-99%). The absolute configuration (R) of the products was confirmed by means of electronic circular dichroism (ECD) spectroscopy supported by theoretical calculations. Selected benzofuryl alpha-azole ketones were also successfully asymmetrically bioreduced by fungi of Saccharomyces cerevisiae and Aureobasidium pullulans species. Racemic and chiral beta-amino alcohols, as well as benzofuryl alpha-amino and alpha-bromo ketones were evaluated for their antibacterial and antifungal activities. From among the synthesized beta-amino alcohols, the highest antimicrobial activity was found for (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-imidazol-1-yl)ethan-1-ol against S. aureus ATCC 25923 (MIC = 64, MBC = 96 mu g mL(-1)) and (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-ol against yeasts of M. furfur DSM 6170 (MIC = MBC = 64 mu g mL(-1)). In turn, from among the tested ketones, 1-(benzofuran-2-yl)-2-bromoethanones (1-4) were found to be the most active against M. furfur DSM 6170 (MIC = MBC = 1.5 mu g mL(-1)) (MIC-minimal inhibitory concentration, MBC-minimal biocidal concentration).