Authors: Sandra Bugdolová¹, Přemysl Lubal¹

¹ Department of Chemistry, Faculty of Science, Masaryk University. Czech Republic

e-mail: bugdolova.sandra@mail.muni.cz

Key words: isotachophoresis (ITP), acetylsalicylic acid (ASA), alkaline hydrolysis, kinetic study

Acetylsalicylic acid (ASA) is known as a weak aromatic carboxylic acid, commonly known under the trade name, Aspirin. It is a white crystalline substance, stable in the air, however, slowly hydrolysing in contact with moisture. The maximal ASA stability appears at pH 2-3, followed by slow hydrolysis at pH 4‑8, which becomes faster at pH 11-12. Hydrolysis of acetylsalicylic acid is extensively studied to better understand the stability in biological systems.¹

Isotachophoresis (ITP) is an electromigration separation technique which, in our study, was used for analysis of drugs², containing ASA. The kinetic conversion of ASA to acetic acid (AA) and salicylic acid (SA) in alkaline medium using ITP technique was also studied.¹ The experimental parameters of ITP analytical procedure (composition and pH of leading and terminating electrolytes, the current and time of analysis) have been successfully optimized to carry out analysis of mixture acetylsalicylic, salicylic and acetic acids. This analytical method could be used for testing of stability of pharmaceutical formulations. In addition, it was used for estimation of rate constants describing the ASA hydrolysis in basic medium. This ITP method was then applied for the quantitative analysis of Aspirin-based drugs by two different approaches which will be in discussed in detail in presentation.

The study was supported by projects (MUNI/A/1421/2022, LTC20044).

References

1 B. Kumar, K.K. Ghosh, P.R. Dafonte: Comparative study of the cationic surfactants and their influence on the alkaline hydrolysis of acetylsalicylic acid. Int. J. Chem. Kin. 2011, 43(1), 1-8.

2 B. Buszewski et al: Electromigration Techniques: Theory and Practice. Springer Berlin Heidelberg 2013.

Authors: Markéta Vejvodová¹, Polina Nadtochaeva², Michael Killinger^1,3, Tomáš Vaculovič¹, Monika Pávková Goldbergová² and Viktor Kanický^1,2

¹Department of Chemistry, Faculty of Science, Masaryk University

²Department of Pathological Physiology, Faculty of Medicine, Masaryk University

³Institute of Analytical Chemistry, Czech Academy of Sciences

e-mail: 474005@muni.cz

Key words: Single-cell analysis, bioimaging, LA-ICP-MS, High-resolution analysis

Nickel (Ni) and titanium (Ti) are most commonly used as joint replacements. In some cases, such as inflammation, bacterial infection or increased mechanical stress can cause these elements to be released and penetrate surrounding tissue or even accumulate in specific organs. Only a few methods can be used for the analysis of ultra concentrations of ions in animal fluids and tissue, but almost no one can also characterize the distribution of the ion. Even though laser ablation inductively coupled plasma spectrometry (LA-ICP-MS) is an analytical method for analyzing an inorganic sample, especially geological ones, today, it is being used more and more to determine the distribution of elements in different types of biological samples Bioimaging using LA-ICP-MS can be used to clarify questions of biomedical research such as bioaccumulation and bioavailability of elements in the tissues and provides insight into the basic chemical composition of living organisms.^{1, 2}

The main objective is to develop a method to determine the distribution of elements at the cellular level, which means a mapping with a resolution at the level of micrometers. From a chemical point of view, a high-sensitivity method for the determination of selected elements (Ni, Ti) in tissues or even in individual cells will be developed and the behavior of these ions in the animal organism will be characterized.

References

1. Mikulewicz et al., Biological Trace Element Research, 142 (2011) 865-889, Cytocompatibility of Medical Biomaterials Containing Nickel by Osteoblasts: a Systematic Literature Review.

2. A. Doble et al., Chemical Reviews, 121 (2021) 11769-11822, Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Imaging in Biology.

Authors: Hubert Veselý¹, Pavel Bobál¹

¹ Department of Chemical Drugs, Faculty of Pharmacy, Masaryk University, Czech Republic

e-mail: 85340@mail.muni.cz

Key words: fluorophore, pyrrole, glycan

Changes in the composition of glycans correlate with the progression of many diseases; therefore, they are investigated as disease markers. However, their analysis is difficult because they do not contain a chromophore or charges that would enable their electrophoretic separation. Our goal was to develop a new fluorescent marker covalently bound to glycans providing fast labelling kinetics, high quantum yield, increased detection sensitivity using mass spectroscopy (MS), and at the same time carrying a charge in the structure, which will enable the studied glycans to be separated electrophoretically.

The basic skeleton of this fluorophore is based on pyrrole and indolizine. The synthesis was based on two building blocks, synthon A and synthon B, which were subsequently connected. The plan was to prepare variants of the fluorophore carrying electron-donating or electron-accepting groups on synthon A. These substitutions allow for variability in the wavelength of the absorption maximum and thus in the wavelength of fluorescence. The molecule also carries a trimethylammonium functional group and a propanoate chain, which is necessary for the attachment of the fluorophore to the glycan.

Synthon B and synthon A were prepared without substitution at the 4-phenyl position and with methyl and methoxycarbonyl groups at this position. The methyl derivative was used for the synthesis of the fluorophore backbone. This structure showed fluorescence in the ultraviolet (UV) region of the spectrum. Subsequently, the substance was oxidized to an aldehyde, which will have to be converted to a quaternary ammonium compound. Additionally, the side chain carrying the methyl ester function will need to be converted to a hydrazide.

The prepared substances will also be characterized in cooperation with the Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic. The usability of the newly developed fluorophores will be demonstrated by profiling glycoproteins associated with breast cancer.

The study was supported by the project MUNI/A/1232/2021.

Authors: Veronika Ballayová¹, Tereza Kauerová², Peter Kollár², Oldřich Farsa¹

¹ Department of Chemical Drugs, Faculty of Pharmacy, Masaryk University

² Department of Pharmacology and Toxicology, Faculty of Pharmacy, Masaryk University

e-mail: ballayovav@pharm.muni.cz

Keywords: thiosemicarbazone derivative of acetophenone, Schiff bases, metalloenzyme inhibitor, aminopeptidase N

Schiff bases, which are carrying imine or azomethine functional group, are versatile pharmacophores capable of forming chelating complexes with various metals. Metal complexes play a crucial role in pharmaceutical sciences due to their wide and significant activities.¹ Synthesized basic thiosemicarbazone and semicarbazone derivatives of acetophenone may be bioactive compounds as well.

Through three-step synthesis it is possible to obtain three arene substitution isomers of basic thiosemicarbazone and semicarbazone derivatives of acetophenone. The initial step of the synthesis is the chloroacetylation of aminoacetophenone, followed by substitution with a secondary amine. Symmetrical secondary amines and heterocyclic amines with saturated heterocyclic skeleton were used for substitution. Final derivatives are obtained in the last step of the synthesis.

Many Schiff bases appear to be important intermediates in a number of enzymatic reactions also due to the above-mentioned complex formation. One of the possible enzymes is aminopeptidase N (AP-N), or membrane alanyl aminopeptidase. This ubiquitous enzyme is a neutral zinc-binding metalloenzyme. Potential inhibitors of AP-N may offer effective and broad-spectrum therapy. Another possible target enzyme is a receptor tyrosine kinase from the class of Epidermal growth factor receptor (ErbB) family. These enzymes are associated with the development of neurodegenerative diseases or with the development of a wide variety of types of solid tumor. Synthesized compounds with the best inhibitory activity on the AP-N enzyme underwent testing for inhibition of cell proliferation on the three different cell lines. A simple QSAR model describing the dependence between the inhibitory activity expressed as IC₅₀ and the descriptors derived from the chemical structure was established.

The study was supported by the project CZ.02.2.69/0.0/0.0/19_073/0016943 Internal grant agency of Masaryk University (MUNI/IGA/0916/2021).

References

1 Sinicropi, M.S.; Ceramella, J.; Iacopetta, D.; Catalano, A.; Mariconda, A.; Rosano, C.; Saturnino, C.; El-Kashef, H.; Longo, P. Metal Complexes with Schiff Bases: Data Collection and Recent Studies on Biological Activities. Int. J. Mol. Sci. 2022, 23, 14840.

Authors: Peter Zubáč¹, Oldřich Farsa¹ and Radka Žáčková¹

¹ Department of Chemical Drugs, Faculty of Pharmacy, Masaryk University

e-mail: peter.zubac@gmail.com

Key words: Piperidinone, One-step synthesis, Reactivity Umpolung, Quaternary salt

Derivatives of 4-piperidinone are of great importance in synthesis of multiple drugs, cosmetics, and industrial chemicals. Classic approach for their preparation from respective primary amines involves mainly Dieckmann cyclisation – a complex multiple-step reaction.

We propose faster and greener alternative – one-step reaction between primary ([hetero]aryl)alkylamine and 4-oxo-1,1-dimethylpiperidinium iodide (from 1-methylpiperidone, a cheap and commercially available reagent and methyl iodide) in EtOH/H₂O mixture under basic conditions (K₂CO₃). Although this reaction Umpolung¹ is known for decades, our added value is in details: omitting vacuum distillation or column chromatography, shrinking to simple Thick-Layer-Silica-Plug filtration using EtOAc:CHCl₃ as a ‘mobile phase’ and dimethylamine (byproduct) scavenging via simple scavenger (sodium acrylate), that is intended to bind dimethylamine via an Aza-Michael Reaction and keep it dissolved in aqueous phase.²

Prepared series of piperidinone derivatives and their thiosemicarbazones will be tested for inhibitory activity against Aminopeptidase N according to the research group practice.

References

1 Willand, N.; Folle, B.; Boutillon, Ch.; Verbraeken, L.; Gesquie`re, J.-C.; Tartara, A.; Deprez, B. Tetrahedron Letters 2007, 48, 5007–5011.

2 Amato, J. S.; Chung, J. Y. L.; Cvetovich, R. J.; Reamer, R. A.; Zhao, D.; Zhou, G.; Gong, X. Organic Process Research & Development 2004, 8, 939-941.