Monatshefte Fur Chemie最新文献

The synthesis and characterization of two Co(II) complexes stabilized by a tridentate SCS pincer ligand are described. Paramagnetic [Co(κ³-SCS^CH2-Et)₂] and [Co(κ³-SCS^CH2-tBu)(κ²-SCS^CH2-tBu)] were obtained via transmetalation protocol from CoBr₂ and S(C-Br)S^CH2-R (R = Et, tBu). Oxidation of the latter with [Cp₂Fe]PF₆ affords the diamagnetic 18 VE complex [Co(κ³-SCS^CH2-tBu)₂]PF₆. X-ray structures and DFT calculations are presented.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-022-02949-1.

New Schiff bases functionalized with amide and phenolic groups synthesized by the condensation of 2-hydroxybenzaldehyde and 2-hydroxyacetophenone with amino acid amides which in turn were prepared in two steps from N-Boc-amino acids and homoveraltrylamine through intermediate compounds N-Boc-amino acids amides. The compounds were characterized by elemental analysis, FT-IR, UV-Vis, and NMR spectroscopy. The crystal structures of three Schiff bases were determined by single crystal X-ray diffraction. There exists O-H $\cdots$ N, N-H $\cdots$ O, and C-H $\cdots$ O types of hydrogen bonds and C-H $\cdots \pi$ secondary bonding interactions in these crystalline solids. The Schiff bases have been screened for anticoagulant and antiplatelet aggregation activities. All the compounds showed procoagulant activity which shortens the clotting time of citrated human plasma in both platelet-rich plasma and platelet-poor plasma except the derivatives of L-methionine which showed anticoagulant activity by prolonging the clotting time. In addition, the compounds derived from benzyl cysteine and phenylalanine showed adenosine diphosphate induced antiplatelet aggregation activity, whereas others did not show any role. Moreover, all these compounds revealed non-hemolytic activity with red blood cells.

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Supplementary information: The online version contains supplementary material available at 10.1007/s00706-022-02936-6.

Glycosylation is one of the most significant and abundant post-translational modifications in cells. Glycomic and glycoproteomic analyses involve the characterization of oligosaccharides (glycans) conjugated to proteins. Glycomic and glycoproteomic analysis is highly challenging because of the large diversity of structures, low abundance, site-specific heterogeneity, and poor ionization efficiency of glycans and glycopeptides in mass spectrometry (MS). MS is a key tool for characterization of glycans and glycopeptides. However, MS alone does not always provide full structural and quantitative information for many reasons, and thus MS is combined with some separation technique. This review focuses on the role of separation techniques used in glycomic and glycoproteomic analyses, liquid chromatography and capillary electrophoresis. The most important separation conditions and results are presented and discussed.

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In this article, we introduce a new communication strategy called the "communication success dimension" for the suppression and eradication of chemophobia. We explain, using recent examples, that chemophobia presents a danger not only to the science of chemistry but also to humankind. Based on the latest insights from communication research, we emphasize the need to bring more passion, dedication, and human factors into the communication of chemistry. We demonstrate the application of this new strategy by employing Marcel Proust's In Search of Lost Time to combat chemophobia.

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Liposomes are nowadays a matter of tremendous interest. Due to their amphiphilic character, various substances with different properties can be incorporated into them and they are especially suitable as a model system for controlled transport of bioactive substances and drugs to the final destination in the body; for example, COVID-19 vaccines use liposomes as a carrier of mRNA. Liposomes mimicking composition of various biological membranes can be prepared with a proper choice of the lipids used, which proved to be important tool in the early drug development. This review deals with commonly used methods for the preparation and characterization of liposomes which is essential for their later use. The alternative capillary electrophoresis methods for physico-chemical characterization such as determination of membrane permeability of liposome, its size and charge, and encapsulation efficiency are included. Two different layouts using liposomes to yield more efficient separation of various analytes are also presented, capillary electrochromatography, and liposomal electrokinetic chromatography.

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This review provides a recent perspective of artesunate and other artemisinins as antimalarial drugs and their uses in cancer therapy. Artesunate is an artemisinin derivative. Artemisinin is extracted from the plant Artemisia annua. Artemisinin and its derivatives have been the most useful drug for malarial treatment in human history. The artesunate has an advantage of a hydrophilic group over other artemisinins which makes it a more potent drug. On the industrial scale, artemisinins are synthesized in semisynthetic ways. The 1,2,4-endoperoxide bridge of artemisinins is responsible for the drug's antimalarial activity. There is the emergence of artemisinin resistance on Plasmodium falciparum and pieces of evidence suggest that it is mainly due to the mutation at Kelch13 protein of P. falciparum. Clinical trial data show that the artesunate is more favorable than quinine and other artemisinins to treat patients with severe malaria. Pieces of evidence indicate that artemisinins can be developed as anticancer drugs. The mechanism of actions on how artemisinins act as an anticancer drug involves oxidative stress, DNA damage and repair, and various types of cell deaths.

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This review provides a brief survey of chiral separation of pharmaceutically active substances published over the last 3 years (2018-2020). Chiral separation of drugs is an important area of research. The control of enantiomeric purity and determination of individual enantiomeric drug molecules is a necessity especially for clinical, analytical, and regulatory purposes. Among chromatographic resolution methods, high-performance liquid chromatography based on chiral stationary phases remains the most popular and effective method used for chiral separation of various drugs. In this review, attention is paid to several classes of chiral stationary phases that have been the most frequently used for drug enantioseparation during this period.

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Targeted cancer treatment is a promising, less invasive alternative to chemotherapy as it is precisely directed against tumor cells whilst leaving healthy tissue unaffected. The plant-derived enzyme horseradish peroxidase (HRP) can be used for enzyme prodrug cancer therapy with indole-3-acetic acid or the analgesic paracetamol (acetaminophen). Oxidation of paracetamol by HRP in the presence of hydrogen peroxide leads to N-acetyl-p-benzoquinone imine and polymer formation via a radical reaction mechanism. N-acetyl-p-benzoquinone imine binds to DNA and proteins, resulting in severe cytotoxicity. However, plant HRP is not suitable for this application since the foreign glycosylation pattern is recognized by the human immune system, causing rapid clearance from the body. Furthermore, plant-derived HRP is a mixture of isoenzymes with a heterogeneous composition. Here, we investigated the reaction of paracetamol with defined recombinant HRP variants produced in E. coli, as well as plant HRP, and found that they are equally effective in paracetamol oxidation at a concentration ≥ 400 µM. At low paracetamol concentrations, however, recombinant HRP seems to be more efficient in paracetamol oxidation. Yet upon treatment of HCT-116 colon carcinoma and FaDu squamous carcinoma cells with HRP-paracetamol no cytotoxic effect was observed, neither in the presence nor absence of hydrogen peroxide.

Supplementary information: The online version contains supplementary material available at 10.1007/s00706-021-02848-x.

The success of chemists in the fight against COVID-19 provides us with a unique opportunity for strengthening the position of chemistry in society and suppressing chemophobia which has badly affected the image and development of chemistry over several decades. By highlighting the unique merits of chemistry in controlling infections and healing diseases, we propose developing a communication strategy "Chemists as children of the Sun". The time is ripe for chemists to take control of the story of chemistry. We believe that chemists must help the public to see chemistry in a whole new light. Only a positive perception of chemistry and the chemical profession will secure a sufficient supply of new talents, ideas, and also financial resources for the development of this unique and irreplaceable science for humanity.

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In this work, we show that intramolecular hydrogen bonding can be used to stabilize tri-coordinated phosphane-gold(I) complexes. Two molecular structures of 2-(diphenylphosphino)benzoic acid (L) coordinated to a gold(I) atom were determined by single-crystal X-ray diffraction. The linear L-Au-Br shows a standard linear coordination and dimerizes via hydrogen bonds of the carboxylic acid. Upon addition of two additional phosphane ligands the complex [L₃Au]X is formed which is stabilized by three intramolecular -C(O)O-H ^… X hydrogen bonds as proven by the X-ray structure of the respective chlorido-complex. X-ray powder diffractograms suggest the same structure also for X^- = Br^- and I^-.

Supplementary information: The online version contains supplementary material available at 10.1007/s00706-021-02843-2.