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Latest Paper:
Ruslan R Kashapov,
Tatiana N Pashirova,
Sergey V Kharlamov,
Albina Yu Ziganshina,
Elena P Ziltsova,
Svetlana S Lukashenko,
Lucia Ya Zakharova,
Wolf D Habicher,
Shamil K Latypov,
Alexander I Konovalov
A. E. Arbuzov Institute of Organic and Physical Chemistry of the Russian Academy of Sciences, 8 Arbuzov Str., Kazan 420088, Russia.
Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration. Beyond ca. 0.4 mM of DABCO-16, mixed aggregates enriched by CR are proved to be formed due to electrostatic forces, while beyond ca. 5 mM, aggregates enriched by surfactant occur due to the hydrophobic effect. Spectrophotometry monitoring of the solubilization of a hydrophobic dye, Orange OT, demonstrated that only the second type of mixed aggregate enriched by DABCO-16 is capable of binding the organic probe, while the mixed system where the surfactant is a minor component shows no binding capacity towards Orange OT. This finding can be used for the design of nanocontainers with controllable binding/release properties.
Vyacheslav E Semenov,
Anatoly S Mikhailov,
Alexandra D Voloshina,
Natalia V Kulik,
Alexandra D Nikitashina,
Vladimir V Zobov,
Sergey V Kharlamov,
Shamil K Latypov,
Vladimir S Reznik
A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center of the Russian Academy of Sciences, Arbuzov str. 8, Kazan 420088, Russian Federation.
Reactions of pyrimidinophanes with two 6-methylthiocytosine and one 5(6)-alkyluracil moieties bridged with each other by polymethylene spacers with methyl or nonyl p-toluenesulfonate, p-toluenesulfonic acid, methanesulfonate and trifluorosulfonate afforded amphiphilic macrocyclic bis-p-toluene-, methane- and trifluorosulfonates. Despite the presence of several reaction centers in the initial pyrimidinophane molecules, protonation and methylation occurred only at the N(1) atom (with quaternization) of the 6-methylthiocytosine moieties. The bacteriostatic and fungistatic activity of the products was estimated. Macrocyclic tosylates exhibit a remarkable selectivity towards Staphylococcus aureus, with MIC values comparable with a reference drug. Bacteriostatic activity of the amphiphilic pyrimidinophanes depends on the size of the macrocycles, and the highest activity corresponds to definite lengths of polymethylene bridges. Besides, the antimicrobial activity of the screened pyrimidine derivatives depends on their topology. While macrocyclic tosylates are more active against bacteria than against fungi, acyclic tosylate with the same structural fragments shows a dramatical decrease of MIC towards mold and yeast with respect to the corresponding macrocycle. It is found that macrocyclic and acyclic tosylates in high dilutions decrease the extracellular lipase activity.
Stefano Chimichi,
Marco Boccalini,
Alessandra Matteucci,
Sergey V Kharlamov,
Shamil K Latypov,
Oleg G Sinyashin
Department of Chemistry, University of Firenze, Firenze, Italy. stefano.chimichi@unifi.it
The combined use of two-dimensional NMR correlation experiments and gauge including atomic orbital density functional theory in (13)C NMR chemical shift (CS) calculations allowed reliable and simple structural determination of regioisomeric heterocyclic systems that originate from the reactions of acylquinolinones with substituted hydrazines. Moreover, the results of differential analysis between the calculated (15)N NMR CSs for hypothetical structures and the experimental data of the title azaheterocyclic systems were even more advantageous with respect to (13)C because there was no need for correlational analysis: structures of the regioisomeric compounds could be determined just by direct comparison.
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