Expanding the Variety of Pyridinium-Based bis-QACs with Antimicrobial Properties: Investigation into Linker Structure-Activity Correlation.

For decades quaternary ammonium compounds (QACs) have served as main component of a top antiseptic and disinfectant compositions. Among them, bis-QACs are the most prominent and effective class of biocides. Although mono-QACs still dominate the antiseptic market, their activity against Gram-negative bacteria is largely inferior to bis-QACs.

Block synthesis of Forssman pentasaccharide GalNAcα1-3GalNAcβ1-3Galα1-4Galβ1-4Glcβ in the form of 3-aminopropyl glycoside.

A total chemical synthesis of spacer-armed Forssman pentasaccharide is reported. The choice of the 2(donor) + 3(acceptor) block scheme, the optimal combination of a limited number of simple protecting groups and the sequence of deprotection steps allowed to achieve the high yield and stereoselectivity of glycosylation and to avoid losses during deprotection. The target pentasaccharide was obtained in a 10-mg scale.

Destabilization of Glycosyl Cation by an Electron-Withdrawing Substituent at C-5 Makes Sialylation Reaction More α-Stereoselective.

Comparison of the reactivity of sialyl chlorides and bromides based on -acetylneuraminic acid (Neu5Ac) and its deaminated analogue (KDN) in reactions with MeOH and -PrOH without a promoter revealed that the acetoxy group at C-5 in a molecule of a sialic acid glycosyl donor can destabilize the corresponding glycosyl cation making the S1-like reaction pathway unfavorable. A change to the S2-like reaction pathway ensures preferential formation of the α-glycoside.

Structural and Serological Characterization of Yet Another New O Antigen, O86, in Clinical Strains.

Bacteria from the genus are facultative human pathogens, primarily attacking the urinary tract and wounds. A total of 85 O serogroups have been identified so far among these bacilli. Bprz 86 was isolated from the fistula of a patient in Łódź, Poland.

Application of the Chitooligosaccharides and Fluorescence Polarization Technique for the Assay of Active Lysozyme in Hen Egg White.

This study describes the applicability of the fluorescence polarization assay (FPA) based on the use of FITC-labeled oligosaccharide tracers of defined structure for the measurement of active lysozyme in hen egg white. Depending on the oligosaccharide chain length of the tracer, this method detects both the formation of the enzyme-to-tracer complex (because of lectin-like, i.e.

Lithocholic Acid's Ionic Compounds as Promising Antitumor Agents: Synthesis and Evaluation of the Production of Reactive Oxygen Species (ROS) in Mitochondria.

The development of a methodology for the synthesis of new compounds with antitumor activity represents a significant and priority task within the field of medicinal chemistry. As a continuation of our research group's earlier studies on the antitumor activity of ionic derivatives of natural compounds, we have synthesized a series of previously undescribed pyrazole ionic compounds through a series of transformations of lithocholic acid methyl ester. To investigate the biological activity of the newly synthesized lithocholic acid derivatives, a series of modern flow cytometry techniques were employed to assess their cytotoxic activity, effects on the cell cycle, and induction of apoptosis.

Electrochemically Mediated Synthesis of Cyanated Heterocycles from α-amino Esters, Pyridine-2-carbaldehydes and NHSCN as Cyano Group Source.

The electrochemically mediated cyanation/annulation process with in situ cyanide ion generation from NHSCN and multi-step oxidative construction of CN-functionalized heterocycles from easily available α-amino esters and pyridine-2-carbaldehydes has been discovered. Depending on the nature of the α-amino ester, 1-cyano-imidazo[1,5-a]pyridine-3-carboxylates, 3-alkyl- and 3-aryl-imidazo[1,5-a]pyridines-1-carbonitriles, and the first reported 4-oxo-4H-pyrido[1,2-a]pyrazine-1-carbonitriles were obtained. The electrosynthesis is carried out in an undivided electrochemical cell under constant current conditions.

Developing Chlorin/Arylaminoquinazoline Conjugates with Nanomolar Activity for Targeted Photodynamic Therapy: Design, Synthesis, SAR, and Biological Evaluation.

In this report, we developed novel chlorin/arylaminoquinazoline conjugates for targeted photodynamic therapy of cancer. The synthesized photosensitizers consisted of chlorin- metallocomplexes (Zn, In, or Pd) conjugated with arylaminoquinazoline ligands with high affinity for epidermal growth factor receptors (EGFR). Additionally, the selectivity and antitumor properties of the conjugates were investigated in the EGFR-expressing A431 human tumor cell line .

The Ground State of Multispin Systems Based on Verdazyl and Nitrene Radicals: An EPR and Quantum-Chemical Study.

In this study, low-temperature EPR spectroscopy and quantum-chemical techniques were employed to investigate multispin systems─1,5-diphenyl-3-(3-nitrenophenyl)-6-oxoverdazyl and 1,5-diphenyl-3-(4-nitrenophenyl)-6-oxoverdazyl─that contain a nitrene center at either a - or -position, respectively. Ground states and magnetic zero-field splitting (ZFS) parameters of these multispin systems were determined by experimental and computational methods. The results indicated that the high-spin quartet state is a ground state, and the quartet-doublet energy gap is close to 10 kcal/mol for the -position of the nitrene group, with ZFS parameters = 0.

Enantioselective Synthesis of Chiral β-Amino Phosphorus Derivatives via Nickel-Catalyzed Asymmetric Hydrogenation.

Compared with chiral β-amino phosphorus compounds, which can be easily derived from natural optically pure α-amino acids, obtaining chiral β-amino phosphorus derivatives remains a challenge. These derivatives, which cannot be derived from chiral natural amino acids, possess unique biological activities or potential catalytic activities. Herein, highly enantioselective hydrogenation for the preparation of chiral β-amino phosphorus derivatives from -β-enamido phosphorus compounds is reported by using a green and low-cost earth-abundant metal nickel catalyst (13 examples of 99% ee).

Comparative Evaluation of Mathematical Model and In Vivo Study of Calcium Phosphate Bone Grafts.

One of the key factors of the interaction 'osteoplastic material-organism' is the state of the implant surface. Taking into account the fact that the equilibrium in regeneration conditions is reached only after the reparative histogenesis process is completed, the implant surface is constantly modified. This work is devoted to the numerical description of the dynamic bilateral material-medium interaction under close to physiological conditions, as well as to the assessment of the comparability of the model with and experimental results.

FeCl-Mediated Rearrangement of Aminoperoxides into Functionalized Tetrahydrofurans: Dynamic Non-innocence of O-Ligands at an Fe Center Coordinates a Radical Cascade.

The selective reaction of cyclic aminoperoxides with FeCl proceeds through a sequence of O-O and C-C bond cleavages, followed by intramolecular cyclization, yielding functionalized tetrahydrofurans in 44-82% yields. Replacing the peroxyacetal group in the peroxide structure with a peroxyaminal fragment fundamentally alters the reaction pathway. Instead of producing linear functionalized ketones, this modification leads to the formation of hard-to-access substituted tetrahydrofurans.

Small molecule ATM inhibitors as potential cancer therapy: a patent review (2003-present).

Introduction: The ataxia telangiectasia mutated kinase (ATM) is key in coordinating the DDR signaling network essential for responding to double-strand breaks (DSBs). Several ATM inhibitors are being investigated for potential anticancer treatment in clinical trials.

Areas Covered: This review aims to provide a comprehensive overview of patents and patent applications since 2003, with a particular focus on the structural properties, activity and efficacy of the claimed ATM kinase small-molecule inhibitors.

Synthesis of branched heterooligosaccharides related to Aspergillus galactomannan containing short Galf side chains.

The members of a widespread Aspergillus fungi genus cause various diseases including the invasive aspergillosis with high morbidity and mortality rates, especially for immunosuppressed patients. One of the main carbohydrate structures on the surface of their cell wall is the galactomannan (GM) which is used in diagnostic kits for the detection of specific types of aspergillosis. However, limited specificity of currently available test systems urges the need for their further improvement.

Synthesis of Renewable Furan-Based Benzoxazines and Polybenzoxazines: Recent Advances.

The burgeoning field of materials science is currently witnessing a paradigm shift toward the utilization of renewable plant biomass as a viable chemical source for the production of sustainable materials. This trend is substantiated by a significant corpus of recent experimental and theoretical research focused on the synthesis and property analysis of such polymers. Within this context, polybenzoxazines stand out as a pioneering class of thermosetting polymers, distinguished by their exceptional thermal and mechanical characteristics, coupled with the feasibility of synthesizing their precursor monomers from eco-friendly, renewable resources, including plant phenols and furfurylamine.

Electrochemically Induced Synthesis of -Allyloxyphthalimides via Cross-Dehydrogenative C-O Coupling of -Hydroxyphthalimide with Alkenes Bearing the Allylic Hydrogen Atom.

The electrochemically induced reaction between alkenes, bearing an allylic hydrogen atom, and -hydroxyphthalimide was investigated. Cross-dehydrogenative C-O coupling with phthalimide--oxyl radical, derived from -hydroxyphthalimide, occurs instead of oxidation of the allylic site, with the formation of a carbonyl group or functionalization of the double C=C bond. The discovered transformation proceeds in an undivided electrochemical cell equipped with a carbon felt anode and a platinum cathode.

Electrochemically driven Michael reaction: synthesis of hydroquinone thioethers.

An original method for the synthesis of a diverse array of hydroquinone thioethers with yields of 36% to 99% under mild conditions is described. The process is voltammetrically controlled and involves electrogenerating active protonated -quinone followed by thiol addition.

Light-Mediated Radical Addition to Azomethine Compounds: Novel Reactivity and Activation Modes.

Azomethines is a class of compounds, which have traditionally served as electrophilic substrates, but their reactions with radicals have long been limited. Photocatalysis provided ample opportunities for promoting these reactions, with wide variety of reagents serving as precursors of radicals. Besides regular addition mode at the azomethine fragment, the oxidative pathway, in which the C=N bond remains in the product, has become possible by proper selection of redox catalyst.

Diverse Cyclization Pathways Between Nitriles with Active -Methylene Group and Ambiphilic 2-Pyridylselenyl Reagents Enabled by Reversible Covalent Bonding.

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is in contrast to what we observed before for other nitriles.

Ammonium Dinitramide as a Prospective N-NO Synthon: Electrochemical Synthesis of Nitro--Azoxy Compounds from Nitrosoarenes.

In this study, the electrochemical coupling of nitrosoarenes with ammonium dinitramide is discovered, leading to the facile construction of the nitro--azoxy group, which represents an important motif in the design of energetic materials. Compared to known approaches to nitro--azoxy compounds involving two chemical steps (formation of azoxy group containing a leaving group and its nitration) and demanding expensive, corrosive, and hygroscopic nitronium salts, the presented electrochemical method consists of a single step and is based solely on nitrosoarenes and ammonium dinitramide. The dinitramide salt plays the roles of both the electrolyte and reactant for the coupling.

Development of Naphthalene-Derivative Bis-QACs as Potent Antimicrobials: Unraveling Structure-Activity Relationship and Microbiological Properties.

While the pandemic is behind us, the world community faces a global threat of bacterial resistance outbreak. One of the key ways to combat the spread of multi-resistant bacteria is infection prevention and control tactics using modern antiseptic and disinfectant compositions. Herein, we continue the path to unravel the structure-activity relationship (SAR) of potent pyridine-derived biocide class bis-quaternary ammonium compounds (QACs).

Azobis(polynitrophenyl-1,2,5-oxadiazoles) as Heat-Resistant Friction-Insensitive Energetic Materials.

The evolution of energetic materials science presents new challenging tasks associated with the creation of advanced technologies for sustainable development of the future. In this work, a set of new heat-resistant high-energy materials incorporating the polynitrophenyl-1,2,5-oxadiazole scaffold enriched with azo/azoxy moieties have been designed and synthesized. Due to a smart combination of explosophoric groups and 1,2,5-oxadiazole rings, the prepared high-energy substances have excellent thermal stability (up to 300 °C), good densities (up to 1.

6-Aryl- and 6,7-diaryl-1,3-dimethyl-1-perimidin-2(3)-ones: synthesis, conformational stability, crystal structure and optical properties.

6-Bromo- and 6,7-dibromo-1,3-dimethyl-1-perimidin-2(3)-ones were arylated with arylboronic acids under Suzuki-Miyaura reaction conditions to afford 6-aryl-, 6-bromo-7-aryl- and 6,7-diaryl-1,3-dimethyl-1-perimidin-2(3)-ones. A comparison of the X-ray structural parameters of -diaryl derivatives of 1,3-dimethyl-1-perimidin-2(3)-one, naphthalene and 1,8-bis(dimethylamino)naphthalene (proton sponge) was performed. Based on the data of dynamic H NMR spectroscopy and quantum-chemical calculations, barriers to /-isomerization of 6,7-diaryl-1,3-dimethyl-1-perimidin-2(3)-ones were estimated.

Photoluminescent chain-of-dimer anion in a novel hybrid halometallate (CHN){SbBr}: atypical behavior in one-dimensional anionic systems.

In pursuit of identifying less toxic hybrid compounds suitable for optoelectronic applications, we synthesized a novel homopiperazinium bromoantimonate(III), (CHN){SbBr}. It readily crystallized from an aqueous hydrobromic acid solution and was found to be stable both in air and upon heating up to 175 °C. The crystal structure of the new bromoantimonate(III) consisted of {SbBr} zigzag chains, which were composed of strongly trigonally distorted SbBr octahedral anions and CHN dications.