Oxazoline scaffold in synthesis of benzosiloxaboroles and related ring-expanded heterocycles: diverse reactivity, structural peculiarities and antimicrobial activity

Abstract

Transformations of oxazoline–benzosiloxaborole conjugates gave rise to novel boracyclic systems as well as functionalized derivatives featuring antibacterial activity.

Ethynyl-substituted benzosiloxaboroles: the role of C(π)⋯B interactions in their crystal packing and use in Cu(i)-catalyzed 1,3-dipolar cycloaddition

“…4.4.2 Determination of antimicrobial activity. The direct antimicrobial activity against yeast, Gram-positive and Gramnegative bacterial strains was evaluated as previously described 17,18 by the disc-diffusion method and the MIC determination assays according to the EUCAST 56 and CLSI 40,57a recommendations. Bactericidal (MBC) activity was performed according to the CLSI recommendations.…”

“…To determine the ability of the Gram-negative bacterial strains to remove new tested compounds by MDR efflux pumps, the MIC values of these agents, with or without the pump inhibitor, PAbN (20 mg L −1 ) (Sigma) were evaluated as previously described. 17,18 To minimize the inuence of PAbN on the destabilization of bacterial cell covers, the tests were conducted in the presence of 1 mM MgSO 4 (Sigma). 58 At least a 4-fold reduction in the MIC value aer the addition of PAbN was considered signicant.…”

“…58 At least a 4-fold reduction in the MIC value aer the addition of PAbN was considered signicant. 17,18…”

“…These relatively simple compounds were converted to derivatives bearing 1-arylsulfonyl-1,2,3-triazole-4-yl moiety. Such a structural design was inspired by our previous results showing that arylsulfonamido 17 arylsulfonato, 18 and (β-phenylsulfonyl)ethylthio 8 substituted benzosiloxaboroles (Scheme 1, general structures III , IV , and V , respectively) exhibit high activity against the Gram-positive cocci such as methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), Enterococcus faecalis and Enterococcus faecium . Based on the presented literature background, 10–16 we assumed that the introduction of 1,2,3-triazole spacer between arylsulfonyl group and benzosiloxaborole might have further positive impact on the antimicrobial potency.…”

Exploring the effect of substitution patterns on the symmetry of hydrogen-bonded supramolecular motifs in functionalized benzosiloxaboroles

“…39 Thus, over one hundred benzosiloxaboroles with diverse substitution patterns have already been obtained with the prospect of being able to synthesize hundreds more. 40–42 We have already published several crystal structures of these compounds but we did not perform their detailed analysis. Herewith, we present a comprehensive study focused on the evaluation of substituent effect on crystal packing of these compounds.…”