Boronate-appended polymers with diol-functionalized ferrocene: an effective and selective method for voltammetric glucose sensing.

In this research, three types of poly(amidoamine) dendrimers doped with a phenylboronic derivative at different ratios of -B(OH)2 groups to amino groups (-NH2) and one polyethyleneimine (PEI) polymer doped with a phenylboronic acid derivative were used as molecular receptors. The voltammetric glucose detection was based on the difference in the affinity of the tested systems in relation to 2-((ferrocenylmethyl)amino)propane-1,3-diol (Fc-1,3-diol) and glucose. Polymeric phenylboronic compounds were introduced to the electrode surface through an electrodeposition process at a constant potential. The obtained calibration curves were characterized by a wide range of linearity (0.005-100 µM) and low values of the limit of detection reaching even 0.0012 µM. Moreover, the influence of interferents (ascorbic acid, uric acid and fructose) was investigated at two different concentrations. Only fructose had a significant influence on the oxidation signal of ferrocene units, but solely in the case of R-Ph-B(OH)2 (where R = PEI or PAMAM; Ph - phenyl ring) systems with a low content of boron groups, and these systems form complexes with glucose in a stoichiometric ratio of 1 : 1. The reliability of the results was confirmed by determining the percentage of recovery (added glucose vs. labeled glucose). Most of the results met the acceptance criteria (95%-105%), allowing the developed electrochemical sensors to be successfully used for the analysis of real-life samples.

Mechanochemical synthesis of antifungal bis(benzoxaboroles).

Several piperazine bis(benzoxaboroles) have been obtained both in solution as well as in the solid state. The environmentally friendly mechanochemical approach - hitherto not applied for the preparation of benzoxaboroles - was particularly beneficial in the case of two products afforded in low yields in solution. The in vitro studies showed high potential of the studied bis(fluorobenzoxaboroles) as antifungal agents, highlighting also the influence of the fluorine substituent position on their microbiological activity. The highest activity against A. niger, A. terreus, P. ochrochloron, C. tenuis and C. albicans was displayed by the analogue of the known benzoxaborole antifungal drug Kerydin® (Tavaborole).

Antifungal activity and tautomeric cyclization equilibria of formylphenylboronic acids.

2-Formylphenylboronic acid and four isomeric fluoro-2-formylphenylboronic acids have been found active against a series of fungal strains: Aspergillus, Fusarium, Penicillium and Candida. The level of antifungal activity was evaluated by agar diffusion tests as well as the determination of minimum inhibitory concentrations (MICs) by serial dilution method. Among the tested compounds, 4-fluoro-2-formylphenylboronic acid - an analogue of the known antifungal drug Tavaborole (AN2690) - proved to be the most potent antifungal agent. The tautomeric equilibrium leading to the formation of 3-hydroxybenzoxaboroles as well as the position of the fluorine substituent were revealed to play a crucial role in the observed activity.

Spectroscopic insight into supramolecular assemblies of boric acid derivatives and ß-cyclodextrin.

Interactions of select boric acid derivatives with ß-cyclodextrin were investigated. All products were obtained employing the grinding-induced mechanochemical approach. It was found that phenylboronic acid, benzoxaborole and boric acid form non-covalent, hydrogen bonding-based systems with ß-cyclodextrin, whereas catechol and pinacol esters of phenylboronic acid as well as ferroceneboronic acid form host-guest inclusion complexes. The interactions were probed using spectroscopic methods: 1H NMR, 1H-1H ROESY NMR, 1H DOSY NMR, FT-IR. Association constant values were evaluated by 1H DOSY NMR. The highest association constant was found for boric acid (117.5 ±â€¯2.5 M-1), whilst the lowest for benzoxaborole (14.8 ±â€¯0.3 M-1). The study shows the influence of boron compound structure on the nature of the assembly formed with ß-cyclodextrin, laying up the basis for future work with such supramolecular systems.

Intramolecular interactions in ortho-methoxyalkylphenylboronic acids and their catechol esters.

Catechol esters of ortho-methoxyalkylphenylboronic acids have been synthesized and characterized by (17)O NMR spectroscopy. The results were compared with the data for the parent acids. The influence of intramolecular and intermolecular hydrogen bonds on the properties of the boronic acids has been discussed. The (17)O NMR data for the boronic esters proved that there are no O → B interactions in the investigated compounds. This fact is connected with weak Lewis acidity of the parent acids and their low sugars' receptors activity. Crystal structure of ortho-methoxyphenylboronic acid catechol ester was determined.

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity.

A halogenmethylsulfonyl moiety is incorporated in numerous active herbicides and fungicides. The synthesis of tribromomethyl phenyl sulfone derivatives as novel potential pesticides is reported. The title sulfone was obtained by following three different synthetic routes, starting from 4-chlorothiophenol or 4-halogenphenyl methyl sulfone. Products of its subsequent nitration were subjected to the S(N)Ar reactions with ammonia, amines, hydrazines and phenolates to give 2-nitroaniline, 2-nitrophenylhydrazine and diphenyl ether derivatives. Reduction of the nitro group of 4-tribromomethylsulfonyl-2-nitroaniline yielded the corresponding o-phenylenediamine substrate for preparation of structurally varied benzimidazoles.