Search

Trimethylsilyl ethers of trifluoromethyl substituted benzyl type alcohols of thiophene and (benzo)furan series undergo multichannel electrophilic transformations in triflic acid CF3SO3H (TfOH). Intermediate cationic species generated from starting heterocycles interact with arenes, leading to the formation of various products of side chain arylation, dehalogenation, arylation of the heteroaromatic core, intramolecular cyclization, hydro-detrimethylsilylogenation, oxo-dehalogenation, and others. The reaction pathway depends on the structure of an intermediate cation, nucleophilicity of the arene, reaction time, and temperature. Plausible mechanisms of these electrophilic reactions are discussed. The obtained trifluoromethyl substituted compounds exhibit good antimicrobial activity against Candida albicans, a yeast-like fungus, at concentrations ranging from 64 to 128 μg mL−1 and inhibit the growth of both Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Various furanic conjugated enones, 4-(furan-2-yl)but-3-en-2-ones and 1-aryl-3-(furan-2-yl)prop-2-en-1-ones, have been synthesized from furfural, 5-hydroxymethylfurfural, and its derivatives by aldol condensation. It has been found for the first time, that reactions of these furanic conjugated enones with arenes under the action of triflic acid or AlCl3 afford the corresponding products of hydroarylation of the furan side chain carbon–carbon double bond in 29–89% yields. According to NMR study and DFT calculations, the corresponding O,C-diprotonated species of furanic enones are the reactive electrophilic intermediates. The obtained furan derivatives demonstrate moderate antimicrobial activity against yeast-like fungi Candida albicans at 64 μg/ml concentration. They also suppress Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Reactions of 3-(furan-2-yl)propenoic acids and their esters with arenes in Brønsted superacid TfOH affords products of hydroarylation of the carbon–carbon double bond, 3-aryl-3-(furan-2-yl)propenoic acid derivatives. According to NMR and DFT studies, the corresponding O,C-diprotonated forms of the starting furan acids and esters should be reactive electrophilic species in these transformations. Starting compounds and their hydroarylation products, at a concentration of 64 µg/mL, demonstrate good antimicrobial activity against yeast-like fungi Candida albicans. Apart from that, these compounds suppress Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]