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[en] Some indices of radiochemical transformations (radiation yields of radicals, changes in infrared absorption spectra) for a number of penicillins having different chemical and crystalline structures have been studied. It has been found that the degree of crystallinity of penicillins may be assessed from their absorption spectra in the infrared and far infrared regions. It has been shown that the greatest radiation resistance is exhibited by those penicillins whcich have a more perfect crystalline structure and contain less water. (author)
[en] A group of sulfonamides exhibiting antimicrobial activity was analyzed with the application of quantitative structure–activity/property relationships method. The purpose of this study was to show the common and differentiating characteristics of the analyzed chemical structures alike physicochemically as well as pharmacologically based on the quantum-chemical calculations both in vacuo and in the aquatic environment together with their microbiological activity and chromatographic retention data. The semiempirical and ab initio level of in silico molecular modeling was performed for calculations of statistically significant molecular descriptors to compare obtained results. The relationship between the structure and biological activity and physicochemical parameters data was able to class and describe analyzed molecules and the applied chemometric approaches (principal component analysis, factor analysis, and multiple regression analysis) revealed the influential features of the tested structures responsible for the antimicrobial activity.
[en] A new synthetic method of 2,5-disubstituted pyrrolidines is developed by the cyclization of unsaturated N-benzoyloxy sulfonamides by (CuOTf)2·C6H6 in refluxing dichloroethane. Various N-4- and N-5-alkenyl and alkynyl N-benzoyloxy sulfonamides are cyclized to give pyrrolidines. The cyclization proceeds via addition of sulfonamidoyl radicals to intramolecular unsaturated bonds or allylic hydrogen abstraction with the radical intermediates
[en] Due to pharmacological importance of 1,3,4-Oxadiazoles, a new series of S-substituted derivatives of 5-(1-(phenylsulfonyl)piperidin-4-yl)-1,3,4-Oxadiazol-2-thiol (4a-v) was synthesized. The reaction of benzenesulfonyl chloride with ethyl isonipecotate yielded ethyl 1-(phenylsulfonyl)piperidine-4-carboxylate (1), which was further converted into 1-(Phenylsulfonyl) piperidine-4-carbohydrazide (2) and 5-(1-(phenylsulfonyl)piperidin-4-yl)-1,3,4-Oxadiazol-2-thiol (3) in the presence of hydrazine hydrate and CS2 along with KOH respectively. The target compounds (4a-v) were synthesized by the reaction of compound 3 with different electrophiles in the presence of DMF and sodium hydride. The structures of all the synthesized compounds were confirmed via IR, 1H-NMR and EI-MS spectral data and were evaluated for antibacterial activity against Gram-positive and Gram-negative bacteria. It was observed that the electrophilic substitution influenced significantly for the variation of antibacterial activity from moderate to excellent level. (author)
[en] This study investigates concentrations of perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFSAs) and perfluoroalkane sulfonamides (FASA) in plasma from ringed seals sampled in the period 1990–2010 (n = 71) in Svalbard, Norway. Perfluorooctane sulfonate was dominant among the perfluoroalkyl substances. PFCAs were dominated by perfluoroundecanoate followed by perfluorononanoate. C4−C8 PFCAs and perfluorooctane sulfonamide (FOSA) were detected in ≤42% of the samples. PFSA and PFCA concentrations were higher in seals sampled from Kongsfjorden, a fjord influenced by strong inflows of Atlantic Water compared to seals from fjords dominated by Arctic Water (e.g. Billefjorden). Sex, age and body condition of the seals did not influence PFAS concentrations. Due to the confounding effect of year and sampling area, temporal trends were assessed only in seals sampled from Kongsfjorden (5 years, n = 51). PFHxS and PFOS concentrations did not show significant linear trends during the whole study period, but a decrease was observed since 2004. Concentrations of all of the detected PFCAs (C9−C13 PFCAs) increased until 2004 after which they have declined or stabilized. - Highlights: • 16 PFASs analyzed in ringed seals from Svalbard sampled 1990–2010 (n = 71). • Higher PFASs in seals from fjords dominated by warmer, saltier Atlantic Water. • Sex, age and body condition had no influence on PFAS concentrations. • C9−C13 PFCAs increased until 2004 after which they have declined or stabilized. • PFOS and PFHxS remained stable in the period 1990–2010. - Concentrations of perfluoroalkyl substances are influenced by hydrographic characteristics of sampling location and sampling year in ringed seals from Svalbard.
[en] We reported highly effective Pd-catalyzed C-C and/or C-N bond formations via C-H activation of aniline derivatives. Considering the lack of regioselective C(sp"2) H hydroxylation of benzylamines, our continued interest in Pd-catalyzed C-H bond functionalization prompted us to investigate the possibility of a Pd-catalyzed ortho-hydroxylation of NH-containing benzylamines. We have developed the Pd-catalyzed ortho-hydroxylation and/or intramolecular oxidative C-C coupling of N-benzyl sulfonamides, which operate through two different postulated mechanistic routes, as depicted in Scheme 2, depending on the reaction conditions.
[en] The first part of the work was to detect antibiotic residues in animal nutriment: chicken, fish, eggs and milk, by methods of screening. The second part covered the development of a new kit for the detection of antibiotic residues. (Author)
[en] The directed ortho-lithiation is demonstrated as an excellent method for additional functionalization of chiral phenyl and naphthyl sulfonamides. The chirality was introduced through sulfonamide formation with a series of chiral amines prior to the lithiation process. In the case of naphthyl sulfonamides the regioselectivity of the directed ortho-lithiation was studied and optimized. The approach was shown to provide facile ortho-functionalization and was applied for the synthesis of chiral 1,2-sulfonamido phosphine derivatives. The latter were evaluated as P,O-ligands in Pd-catalyzed asymmetric allylic substitution. Graphical abstract: .