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  • Open access
  • 30 Reads
New photochemical properties of azidoaniline and ciprofloxacin.

There is a trend to find new ways of using photocatalysis in order to synthesize valuable products or to control or track live processes with special fluorescence-based molecular probes. The paper presents some results concerning new photochemical properties of para-azidoaniline, its 7-nitrobenzofurazan (NBD) derivative and ciprofloxacin derivatives. Ciprofloxacin (CPF) emits blue fluorescence as well as generates free radicals during photolysis. Its hydrophobic derivatives can be used as fluorescent photoinitiators showing antimicrobial properties. It was found out that the CPF itself, N-hexanoyl (CPF-Hex) and some other derivatives of ciprofloxacin exhibit the properties of a photoinitiator for polymerization under UV light (365 nm) on the model system of aqueous alcoholic solutions of acrylamide and N,N'-methylene bis-acrylamide, and that part of CPF-Hex molecule is capable of binding with the polymer chain covalently. A reaction between nitrobenzoxadiazole derivative of para-azidoaniline (NBD-azidoaniline) and hexyne-1 was studied. NBD-compounds can fluoresce, hence they are potentially applicable as molecular probes and for disease diagnostics, but their photochemistry wasn’t studied comprehensively. Eventually, the mixture of NBD-azidoaniline and hexyne-1 yielded the yellow fluorescent product under 365 nm UV light, whereas copper-catalyzed reaction gave a purple compound. Azidoaniline photolysis was studied in acetonitrile and methanol using UV-Vis spectroscopy resulted in monitoring of a new red fluorescent product formation in the first case. Elucidation of the processes might allow developing new molecular probes and photodynamic therapy agents. The work was supported GSPR (Belarus) № 20210560.

  • Open access
  • 47 Reads
A combined 2D- and 3D-QSAR study, design and synthesis of some monocarbonyl Curcumin analogs as potential inhibitors of MDA-MB-231 breast cancer cells.

Breast cancer is the most frequently diagnosed life-threatening cancer in women. As a result, there is a critical need for the development of a safe and effective drug therapy for its treatment. Curcumin, a secondary metabolite isolated from Curcuma longa, has been shown to exhibit an impressively broad range of pharmacological effects. Despite its powerful interaction with a diverse set of cellular targets, Curcumin has several drawbacks that limit its potential as a therapeutic agent. One of the most common approaches to overcoming these limitations is the design and synthesis of novel Curcumin analogs. This study was conducted in support of the ongoing search for new molecules that are effective enough for the treatment of Triple-negative breast cancer while causing only minor side effects. Hence, several symmetrical monocarbonyl analogs of Curcumin with cyclopentanone, cyclohexanone and 4-piperidone as central core, were synthesized by Claisen-Schmidt condensation reaction. Their structures were identified by measuring the melting points, as well as using FTIR and UV/VIS spectroscopic techniques. To assess the cytotoxic activities of the analogs against MDA-MB-231 Breast Cancer Cells and to identify the significant structural features responsible for these molecules' potency, combined 2D- and 3D-Quantitative structure-activity relationship (QSAR) models were developed. The generated QSAR models demonstrated acceptable internal validation, as well as good external predictive capacity, indicating that they can be used to design similar compounds. These results suggest that the synthesized candidate drugs have promising cytotoxic potential against MDA-MB-231 cancer cells and should be further investigated both in vitro and in vivo.

  • Open access
  • 28 Reads
Сu-catalyzed Pinner reaction of acetonitrile with alcohols

The Pinner reaction refers to the acid catalysed reaction of a nitrile with a variety of nucleophiles under anhydrous acidic conditions, affording a useful key intermediate salt for agrochemical and medicinal research. Acid catalyzed reaction of carbonitriles with alcohols gives an imino ester salts, another versatile heterocyclic building block found in various chemicals and pharmaceutics. However severe reaction conditions prevent the wide application of this reaction. We found that the reaction of primary alcohols with acetonitrile under the action of a CuBr2 catalyst gives esters in 83-95 % yield. The reaction we discovered paves the way for the use of copper catalysis in the Pinner reaction.

  • Open access
  • 35 Reads
High-throughput virtual screening of compounds with electrophilic fragments for new potential covalent inhibitors of bacterial proteins

Search for new antibacterial drugs has continued to be an urgent request. One of the approaches is development of covalent inhibitors using biochemoinformatics at initial stages. In this work, structures of few plant-derived substances with electrophilic unsaturated carbonyl & structures of small synthetic compounds suitable for fragment-based drug discovery (FBDD) with -CH2-Br group were selected as ligands for set of >500 PDB structures of bacterial proteins. Theoretical assessment was carried out using the Autodock Vina program for calculation and FYTdock for organization the process and analysis of results. Based on the docking simulations, ixerin D from dandelion has been identified as a potential covalent inhibitor of mycobacterial lipoyl synthase (PDB code: 5EXI), inosine monophosphate dehydrogenase (4ZQR), beta-ketoacyl-acyl-transferring synthase III proteins with localization of its electrophilic fragment within 0.4 nm from the cysteine sulfur atom and binding energies ranging from -9.0 to -10.7 kcal/mol. For the synthetic ligand 4-(4-(2-bromoethyl)piperazin-1-yl)-7-nitrobenzofurazan, affine binding (docking score from -6.5 to -7.3 kcal/mol) with the orientation of the -CH2-Br to the Cys sulfur atom of Sortase B from Staphylococcus aureus, which is important for pathogenesis, E. coli Gsp amidase and β-lactamase S70C BlaC has been shown. Similar binding of 2-bromo-1-(4-(nitrobenzofurazan-4-yl)piperazin-1-yl)ethanone with respect to histidine residues of Microcin-processing metalloprotease from E. coli, CYP134A1 from Bacillus subtilis and 10 other proteins has been observed. 2-bromo-N-(4-bromophenyl)acetamide demonstrated ability to covalent Cys modification for only A264C of P450 BM3 from E. coli. Thus, the compounds may have potential antibacterial properties opening up promising directions for further experimental studies in vitro.

  • Open access
  • 20 Reads
Synthesis of carbazolyl imidazo[1,2- α] pyridines via Groebke-Blackburn-Bienayme reaction under green catalyst
, , , ,

Multicomponent reactions (MCR) are efficient and versatile synthetic tools, they also have several advantages such as high convergence, operational simplicity, atomic economy, friendly conditions, and MCR products are obtained with good to excellent overall yields. The Groebke-Blackburn-Bienaymé (GBB) multicomponent reaction based on isonitriles (MCR-I) in the synthesis of imidazo[1,2-α]pyridines (IMP) under green catalyst like montmorillonite K-10 has been little reported. Therefore, the present work describes the novel ultrasound-assisted one-pot synthesis for analogs of imidazo[1,2-α] pyridines (IMPs) incorporating the carbazole.

  • Open access
  • 45 Reads
Synthesis, Characterization and Biological Activity of Hydrazones and Their Copper(II) Complexes

With the emergence of multidrug resistant pathogens and hence a lack of potent antibiotics, the search for novel antibacterial agents has become of interest. Hydrazones are known to exhibit biological activity against bacteria, viruses and fungi. Nitrofurantoin is widely used in the treatment of infectious urinary tract diseases as an antimicrobial agent inhibiting metabolic enzymes of several Gram-positive and Gram-negative bacteria. Ftivazide demonstrates potent antimycobacterial activity in the therapy for tuberculosis.

Hydrazones represent a class of synthetically accessible organic compounds possessing versatile coordination chemistry with a wide range of metal ions. Copper is an element of fundamental importance for the formation and functioning of several enzymes, such as cytochrome с oxidase and Cu/Zn superoxide dismutase.

Cu(II) coordination compounds with nitrofurantoin, ftivazide and 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde derived hydrazones were synthesized and characterized by means of elemental analysis, FT-IR spectroscopy, UV-Vis spectroscopy, NMR spectroscopy and XRD analysis, as well as in vitro biological activity assays. Hydrazones were prepared by the reaction of aromatic hydrazides with 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde using anhydrous methanol as a solvent.

Formation of Cu(II) complexes with hydrazones might enhance therapeutic efficacy and reduce toxicity of uncomplexed organic ligands. This could be due to the interaction of Cu(II) ion with N,O binding moieties resulting in charge delocalization and overall increase in lipophilicity of the system, which facilitates its cell membrane penetration. Novel copper(II) complexes with antibacterial activity are promising chemotherapeutic agents for medicinal chemistry.

  • Open access
  • 23 Reads
Antibacterial activity of Ag2O/SrO/CaO nanocomposite

The increase in bacterial resistance to one or several antibiotics has become a global health problem. Nanocomposite have become a tool against multidrug-resistant bacteria. A nanocomposite, Ag2O/SrO/CaO was prepared from AgNO3, SrCl2.6H2O, CaCl2, and a solution of Na2CO3 via calcination of the salts mixture. The nanocomposite was successfully prepared by the co-precipitation method and completely according to green chemistry, both in terms of synthesis method, solvent and precursors. The nanocomposite was characterized by XRD, XRF, FESEM analyses. Afterwards, the nanocomposite was applied for antibacterial activity against gram-positive and gram-negative bacteria including PS Aeruginosa, Keleb peneumonia, Staph coccus aureus, Staph sapropphyticus, and Esherichia coli.

  • Open access
  • 34 Reads

To address the multifactorial nature and complexity of Alzheimer’s disease (AD), the search for new multitarget agents is emphasized. Three molecular targets for the treatment of this disease are the enzyme acetylcholinesterase (AChE), the nicotinic acetylcholine receptors (nAChR) and monoamine oxidases (MAO) enzymes. In a previous work, we confirmed that caffeine-pyrrolidine hybrids can inhibits AChE activity and activate both muscle and α7 nAChRs with high potency. Based on this background, we have designed and synthesized new caffeine analogues, with the aim of obtaining more powerful multifunctional derivatives destined to stimulate cholinergic signage.

Appling once again a simple and efficient methodology developed in our research group, a series of new derivatives were synthesized from theophylline as starting material. This natural alkaloid reacted with the corresponding dibromoalkane (n= 6, 8) and subsequently with a secondary amine (pyrrolidine, piperidine, diethylamine and 1-methylpiperazine). These two synthetic steps were carried out in a microwave reactor (CEM Discover). All the new caffeine analogues inhibited AChE. Among them, compound Teof-C6-DEA (7-(6-(diethylamino)hexyl)-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione) showed the strongest effect (IC50 = 0.14 µM) on AChE. Complementary studies are being carried out on their activity as MAO inhibitors and as nAChR activators.

  • Open access
  • 32 Reads
Reuse of a recovered, spent hydroprocessing catalyst in Indole acylations using cyclic anhydrides
, , , , , ,

Spent, wasted hydroprocessing catalysts from a petrochemical refinery were recovered from a consecutive draining-solvent extraction–calcination strategy. The activity of these recovered heterogeneous catalysts was evaluated in the acid-mediated indole acylation process. Thus, Bis-(indol-3-yl)-alkane diones were obtained when indole was reacted with cyclic anhydrides in presence of DMF as solvent and catalytic amounts of a spent hydroprocessing catalyst waste. In contrast, reaction between indole and phthalic anhydride afforded phthalimide in as major ptoduct

  • Open access
  • 34 Reads
A modified Silver-Egg shell Nanocomposite applied for Antibacterial activities

Bacterial infections have one of the extensive impacts on public health. Therefore, finding compounds with antibacterial properties could serve as an effective method. A nanocomposite, Ag/CaO was prepared from silver nitrate and egg shells. After calcination of egg shells, the remaining solid, CaO was cooled, then silver nitrate was added and the mixture was ground to a fine powder, and finally heated to 300 C. The brown solid obtained was characterized by XRD, SEM and XRF methods. The prepared Ag/CaO was exmained for antibacterial activity against gram-positive and gram-negative bacteria including keleb pneumonia, staphylococcus aureus, Esherichia coli. This work has a similar paper published in 25th ECSOC 2021, but now we made two changes including the amount of silver nitrate and calcium oxide in the synthesis route, and the size of the first synthesized nanocomposite by grinding with a ballmill, and then we examined these two substances against the bacteria. In fact, changing the amount of silver, known as the antibacterial metal, was compared to the changing the size of the nanocomposite, which could have more antibacterial effect.