Alexander V. Finko

This review analyzes the current methods of synthesis and applications of pyrazole derivatives― one of the most significant classes of five-membered nitrogen-containing heterocycles. The role of the pyrazole ring as a key pharmacophore in the structure of modern pharmaceuticals is reviewed. Special attention is paid to the use of nitrogen-rich pyrazoles as promising, environmentally friendly energetic materials characterized by high thermal stability and low sensitivity. The urgency of developing new synthetic approaches to the targeted design of functionalized pyrazole systems possessing a specific complex of physicochemical and biological properties is substantiated.

We report the synthesis and single-crystal X-ray structures of three novel (Z)-5-arylidene-3-phenylrhodanine derivatives, differing in the substituents on the benzylidene fragment (two methoxy groups (compound I), a dioxine ring (compound II), or a dioxole ring (compound III)). Despite the overall similarity of the molecules, their supramolecular architectures were found out to be strikingly different. The results of intermolecular interactions in those structures are investigated via Hirshfeld surface, molecular electrostatic potential surface and non-covalent interaction analyses. The fine modulation of the arylidene substituent can switch the primary intermolecular synthon from weak S···S bonding to n···π* interactions, offering new possibilities for crystal engineering of rhodanine-based materials.

We report the synthesis and single-crystal X ray structures of three novel (Z)-5 arylidene-3-phenylrhodanine derivatives, differing in the substituents on the ben-zylidene fragment (two methoxy groups (compound I), a dioxine ring (compound II), or a dioxole ring (compound III)). Despite the overall similarity of the molecules, their su-pramolecular architectures were found out to be strikingly different. In both compounds I and II, short S···S chalcogen bonds together with forced C–H···O hydrogen bonds generate dimeric motifs, whereas III lacks S···S interactions and instead features an n→π* contact from the rhodanine carbonyl oxygen to the benzodioxole ring, as well as C-H···S bifurcate hydrogen bond. The results of intermolecular interactions in those structures are checked via Hirshfield surface analysis. The fine modulation of the arylidene substituent can switch the primary intermolecular synthon from chalcogen bonding to n→π* interactions, offering new possibilities for crystal engineering of rhodanine-based materials.

This work describes the thermal synthesis and structural optimization of Fe3BO ₆ nanoparticles (NPs) as boron‐containing precursors for nanostructured Nd–Fe–B permanent magnets. Amorphous Fe ₃ BO ₆ NPs were obtained by chemical precipitation from FeCl ₃ /NaBH ₄ solutions and crystallized by controlled heat treatment. Phase evolution was monitored by TG–DSC, XRD, and FTIR, while SEM, TEM, and DLS characterized morphology and size distribution. Annealing at 530°C yields Fe ₃ BO ₆ ·3 α ‐Fe ₂ O ₃ NPs with a narrow size distribution (50 ± 10 nm) and reduced aggregation, suitable for chemically assisted nanostructuring. These optimized NPs, combined with Nd ₂ O ₃ and Fe ₂ O ₃ , were used in a reduction–diffusion route to prepare Nd–Fe–B alloys with different nominal compositions. The best composition, Nd ₁₆ Fe ₇₆ B ₈ , forms single‐phase Nd ₂ Fe ₁₄ B and exhibits high coercivity (Hc = 8439 Oe) with stable remanence, surpassing several reported chemically synthesized Nd–Fe–B systems. The use of simple inorganic precursors, moderate temperatures, and controlled nanoscale structure makes this Fe ₃ BO ₆ ‐based route attractive for scalable, resource‐efficient production of powders for advanced bonded magnets and other high‐performance applications.

A wide class of 3-hydroxyisoindolinones can be prepared from o-keto acids and both alkyl and aryl amines using PyBOP, PyBrOP, HATU, HBTU, and the like, under mild conditions, typically at 5-25 °C in DCM with Et₃N as base. Both EWG- and EDG-bearing o-keto acids have been studied and the yields range from 40% up to 90%. In some cases, the intermediate activated keto ester has been isolated in crystalline form. The amine attack on the keto ester leads first to the amide formation followed by an intramolecular cyclization step, as revealed by computational mechanistic studies.

Solution properties of amphiphilic polyoctenamers functionalized with short polyethylene glycol side chains in the 3rd and 5th positions are compared using light scattering and diffusion-ordered spectroscopy. To that end, 3- and 5- succinyl cyclooctenes are synthesized in several steps, starting from cyclooctene and 1,5-cyclooctadiene, respectively, then grafted with oligoethylene glycol methyl ether, and involved as monomers in ring-opening metathesis polymerization on the second-generation Grubbs catalyst. In the case of 3-succinyl cyclooctene, the polymerization proceeds in a regio- and stereoselective manner to afford macromolecules with full head-to-tail regioregularity and trans-stereoregularity. Although both 3- and 5-functionalized polyoctenamers form micelles in water and chloroform above certain concentrations and exhibit a cloud point on heating, it is found that regularly positioned pendants lower the tendency to aggregation more efficiently, which can be important for all applications involving the use of amphiphilic polymer brushes.

Various 5-phosphono-hydantoins resembling SF2312 and bearing phosphonate moiety can be prepared from the starting hydantoins by a previously described two-step process via sequential bromination and phosphorylation to yield diethyl 5-phosphono-hydantoin esters followed by facile removal of ethyl groups. The insights of two-step bromination and phosphorylation were analyzed and described in respect of the known literature data. Given the structural similarity between hydantoin derivatives and glyphosate, we propose that hydantoins with a phosphonate group could serve as potential modulators of EPSP synthase mimicking glyphosate’s binding interactions and disrupting the shikimate pathway. During a test on hypersensitive E. coli strains, some hydantoins bearing phosphonate moiety showed a slight antibiotic activity and additionally were shown to have phytotoxicity causing local chlorotic lesions on punctured leaf segments of three plant species. Molecular modelling was applied to understand the biological activity of synthesized hydantoins.