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A method for the synthesis of mixed-ligand gold glyconanoparticles with average particle size of 20–25 nm at widely variable ratio of the initial glycoligands on the basis of aldoses 6-mercaptohexanoyl hydrazones—condensation products of a series of natural aldoses (N-acetylamino-D-glucose, D-mannose, D-galactose, and L-fucose) with 6-mercaptohexanoic acid hydrazide—has been developed. It has been shown that the obtained gold glyconanoparticles exhibit low toxicity and are active against influenza A/Puerto Rico/8/34 (H1N1) virus at concentrations of 3 and 6 μg/mL.

A method for the synthesis of gold glyconanoparticles with average particle size of 18–21 nm and low polydispersity index based on readily available thiolated compounds: 3-thiopropionylhydrazones of L-fucose, L-rhamnose, N-acetyl-D-glucosamine, and N-acetyl-D-mannosamine has been developed. It has been shown that some of the gold glyconanoparticles exhibit antitumor activity, and the initial thiolated glycoligands have shown strong radioprotective activity, increasing the survival rate of mortally irradiated mice by 50–70%.

In experiments in mice, the radioprotective efficacy of sugar-containing compounds was studied based on the condensation products of thioglycolic (TGH) and thiosalicylic (TSH) hydrazides with a series of natural aldoses: the monosaccharides D-glucose (Glс) and D-galactose (Gal) and the disaccharides D‑lactose (Lac) and D-maltose (Mal). It was shown that the use of Glc-TGH and Mal-TSH preparations increases the survival rate of deadly irradiated animals by 25% when administered 1 h before irradiation and by 40% when administered 24 h before irradiation. It is assumed that the leading role in the radioprotective activity of the drugs is played by the protection of the hematopoietic stem cells of the test animals.

Contemporary art within the last thirty years has developed new types and forms of representation. This process was strongly supported by the emergence of the institution of independent curatorship. The phenomenon of an independent curator of the actual art scene has been determined by certain circumstances. The first is, if not paradoxical, a poorly structured market for contemporary art. This makes it possible for curatorial initiatives to have greater maneuverability. Secondly, the flexibility of the cultural field in St. Petersburg, without a hierarchical framework, has allowed artists to vary the ‘palette’ depending on the concept of a project. And finally, the social status of the curator, not as a person of a certain profession, but as a kind of activity corresponding to the role of a free agent, or according to Harald Zeeman, “Gastarbeiter of spirit”. Apart from the galleries with definite commercial goals, there are many public spaces for the realization of curators’ projects. Moreover, there still exists a living tradition of consolidated artistic groups, totally prepared for representation of their activities. Aesthetic preferences, types of creativity, and forms of artistic activity are embodied in the choice of certain curatorial strategies. The artists themselves can work as curators, thus combining several functions. Recently, a new generation of curators has appeared in St. Petersburg who actively promote local art on the international scene. Having emerged in the 1990s, the institution of curatorship has not yet become a subject of comprehensive scientific research. Meanwhile, the very existence of art itself to a great extent depends on its representation shaped by curators’ artistic will.

Using numerical simulation in the CAFE module of the ProCast commercial program, a study was performed of the competitive growth of grains in the seeding unit of the setup to obtain single crystal castings of nickel-base heat-resistant alloy in the process of directional crystallization using the Bridgman method. Using the example of a flat crystal selector, the mechanism of selection of a single grain from several grains with a close axial and arbitrary azimuthal orientation has been considered. It has been found that a significant role in the grain selection is played by the position of the grain in the input section of the crystal selector system. The initial growth advantage comes to those grains that lie in the zone of the crystallization front, from which the way for an unimpeded growth along the crystallization channel is opened. The position of this zone changes as the front moves in the curvilinear channel of the crystal selector. The main tool for selecting a single grain from a variety of closely oriented grains is a change in the position of the zone that is favorable for unimpeded growth. The continuous cyclic change of the zone of favorable growth, which occurs while the grain grows in the helicoid crystal selector, leads to a rapid selection of one grain. In a flat zigzag-shaped crystal selector, the zone of the favorable growth changes only a limited number of times, so this crystal selector is less efficient. The described mechanism of grain selection is applicable in the case of crystal selectors with an angle between the channel axis and the vertical axis Z of no more than 45°, i.e., when the primary axes of dendrites are formed in the crystallographic direction [001].

The aim of the present study is investigation of the impact of mass development of cyanobacteria and Elodea on population characteristics (abundance, biomass, fecundity) and "health" parameters (the state of embryos, heart rate, and thermal resistance) of aquatic invertebrates in experiments with controlled conditions. In July-August 2018, in four variants of microcosms, the conditions were modeled characteristic of the coastal zone of the Rybinsk Reservoir in the period of mass development of cyanobacteria. Mass species were placed in microcosms of planktonic (with domination (80%) Daphnia longispina) and bottom animals (Unio pictorum, Gmelinoides fasciatus, Asellus aquaticus), as well as Elodea canadensis. In the variants with cyanobacteria, the toxic microcystins LR were revealed (24-53% of the sum of toxins, or from 6.6-66.5 μg/L). The presence of cyanobacteria (Aphanizomenon flos-aquae, Microcystis aeruginosa, and Gloeoitrichia spp.) influenced structural parameters of plankton: the quantity to green algae decreased, small-sized crustaceans increased. Influence of cyanobacteria caused reliable changes in parameters of aquatic animal from those of the control: thermal resitance of mollusks and amphipods decreased, time of restoration of heart rate after loads (salinity test) in mollusks increased; in amphipods, individual fecundity decreased, frequency of abnormalities and of mortality of embryos increased. The presence of Elodea intensified these effects. Thus, mass development of cyanobacteria and Elodea influences ecological-physiological parameters of aquatic animals, decreasing their adaptivity to natural stresses and deteriorating the quality of the progeny.

The paper is devoted to the consideration of the main reasons for the failure of various kinds of electromechanical instrument assemblies, caused by the occurrence of local defects in the material of the critical parts. The physical nature of the appearance of such defects, which is caused by discrete inclusions in the materials of parts, is disclosed. The origin of local defects largely affects the appearance of external vibration effects and dynamic processes in the nodes of the mechanisms of the devices and their further functioning and quality of work. A mathematical form of accounting for local defects when creating a mathematical model for describing a node of a mechanical system using Fourier analysis is given. The possible directions of development of local defects in the nodes of the system and the consequences of them are shown, and attention is also focused on the proposed methods for eliminating these defects in the manufacture of parts.

A procedure has been developed for the synthesis of gold glyconanoparticles with an average particle size of 15–30 nm and a low polydispersity index on the basis of natural hexose (d-glucose, d-galactose, d-mannose) sulfanylacetyl-, 3-sulfanylpropanoyl-, and 2-sulfanylbenzoylhydrazones and thiolated poly(2-deoxy-2-methacryloylamino-d-glucose).

A procedure has been developed for the synthesis of previously unknown aldose 4-[(ω-sulfanylalkyl) oxy]benzoylhydrazones (where alkyl is hexyl or decyl and aldoses are D-glucose, D-galactose, D-maltose, and D-lactose) that a repromising glycoligands for noble metal nanoparticles. According to the 1H and 13C NMR data, 4-[(ω-sulfanylalkyl)oxy]benzoylhydrazones derived from D-glucose, D-maltose, and D-lactose in crystal and in DMSO-d6 solution have exclusively the cyclic pyranose structure (α- and β-anomers). D-Galactose 4-[(ω-sulfanylalkyl)oxy]benzoylhydrazones in DMSO-d6 solution exist as tautomeric mixtures of cyclic pyranose and open-chain acylhydrazone structures.

Journal of Instrumentation 16(04), T04001 (2021). doi:10.1088/1748-0221/16/04/T04001, The CMS experiment at the CERN LHC will be upgraded to accommodate the 5-fold increase in the instantaneous luminosity expected at the High-Luminosity LHC (HL-LHC) [1]. Concomitant with this increase will be an increase in the number of interactions in each bunch crossing and a significant increase in the total ionising dose and fluence. One part of this upgrade is the replacement of the current endcap calorimeters with a high granularity sampling calorimeter equipped with silicon sensors, designed to manage the high collision rates [2]. As part of the development of this calorimeter, a series of beam tests have been conducted with different sampling configurations using prototype segmented silicon detectors. In the most recent of these tests, conducted in late 2018 at the CERN SPS, the performance of a prototype calorimeter equipped with ���12,000 channels of silicon sensors was studied with beams of high-energy electrons, pions and muons. This paper describes the custom-built scalable data acquisition system that was built with readily available FPGA mezzanines and low-cost Raspberry Pi computers., Published by Inst. of Physics, London

Journal of Instrumentation 16(04), T04002 (2021). doi:10.1088/1748-0221/16/04/T04002, As part of its HL-LHC upgrade program, the CMS collaboration is developing a High Granularity Calorimeter (CE) to replace the existing endcap calorimeters. The CE is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic (CE-E) and hadronic (CE-H) compartments. The calorimeter will be built with ���30,000 hexagonal silicon modules. Prototype modules have been constructed with 6-inch hexagonal silicon sensors with cell areas of 1.1 cm2, and the SKIROC2-CMS readout ASIC. Beam tests of different sampling configurations were conducted with the prototype modules at DESY and CERN in 2017 and 2018. This paper describes the construction and commissioning of the CE calorimeter prototype, the silicon modules used in the construction, their basic performance, and the methods used for their calibration., Published by Inst. of Physics, London

A procedure has been developed for the synthesis of gold glyconanoparticles with an average particle size of 16–24 nm and low polydispersity index on the basis of accessible D-maltose and D-maltose 2-sulfanylacetyl-, 3-sulfanylpropanoyl-, and 2-sulfanylbenzoylhydrazones.

A method of synthesis of silver glyconanoparticles with average particle size 15–40 nm and low polydispersity index based on available 3-thiopropionylhydrazones of mono- and disaccharides has been elaborated. The prepared compounds have exhibited high antifungal, antibacterial, and antiviral activity and are promising for further comprehensive study.

The accessible D-ribose mercaptoacetyl-, 3-mercaptopropionyl-, and 2-mercaprobenzoylhydrazones were used to develop a method of synthesis of gold glyconanoparticles with the average particle diameter of 10–40 nm and a low polydispersity index.

A method of synthesis of 3-thiopropinyl derivatives of 5-oxo-1,3,4-benzothiadiazepine-4-acetic acid, potential antihypertensive drugs, vasopeptidase inhibitors, starting from 2-thiobenzoic acid hydrazide has been elaborated.

Basing on natural amino acid L-cysteine, commercially available aliphatic aldehydes, 2-acetylsulfanylbenzoyl chloride and 2,2′-disulfandiyldibenzoyl dichloride a synthesis was developed of (2R,4R)-2-alkyl-3-(2-mercaptobenzoyl)thiazolidine-4-carboxylic acids, potential antihypertensive compounds, inhibitors of angiotensin transforming enzyme.

Radical copolymerization of N-vinylpyrrolidone and 2-aminoethyl methacrylate hydrochloride has been studied. Molecular and hydrodynamic characteristics of the resulting copolymers have been determined, and their structure has been confirmed. Conditions favoring conversion of these copolymers into copolymers of N-vinylpyrrolidone with 2-aminoethyl methacrylate of different composition have been elucidated. The suitability of the prepared copolymers as polymeric carriers of monofluoroquinolone ofloxacin has been demonstrated.

It has been shown by 1H and 13C NMR spectroscopy that 2-mercaptobenzoyl-hydrazones of aliphatic and aromatic aldehydes exist in solution as tautomeric mixtures of linear and cyclic benzo-1,3,4-thiadiazepine forms. The linear hydrazone form is represented by (E,E')-and (E,Z')-conformational isomers, differing in the disposition relative to the amide C–N bond. Growing bulk of the alkyl substituent at the C=N bond of the aliphatic aldehydes derivatives decreases the fraction of the cyclic tautomer; therewith the logarithms of the constants of the chain-ring tautomeric equilibrium correlate with the ES steric constants of the alkyl substituents. In the series of the aromatic aldehydes 2-mercaptobenzoylhydrazones the linear tautomer prevails, and the logarithms of the tautomeric equilibrium constants KT correlate with the σ-constants of the substituents in the aromatic nucleus.

A device for fabricating thin-wall (straw) drift tubes using polyethylene terephthalate film 36 μm thick by ultrasonic welding is described together with the technique for controlling their quality. The joint width amounts to 0.4–1.0 mm. The joint breaking strength is 31.9 kg/mm2. The argon leakage from a tube of volume 188.6 cm3 under a pressure gradient of 1.0 atm does not exceed 0.3 × 10–3 cm3/min, which is mainly related to the absence of metallization in the joint vicinity. The high strength, the low tensile creep due to the absence of glued layers, the small value of gas leakage makes the new tubes capable of reliable and long-term operation in vacuum, which is confirmed by the operation of 7168 straw tubes for two years in the NA62 experiment.

Using numerical simulation in the ProCAST program complex, the conditions of the solidification of heat-resistant nickel alloy in curvilinear channels of a ceramic mold have been investigated. It has been shown that, in practically important cases, the vector of the temperature gradient is oriented along the axis of the curvilinear channel. In a spiral crystal selector, a cyclic change in the preferred direction of growth occurs because of the cyclic change in the direction of the vector of the temperature gradient. The fact that the vector of the temperature gradient is almost always directed along the axis of the curvilinear channel makes it possible to govern the orientation of the vector of the temperature gradient in space and, therefore, to obtain a grain with the preferred crystallographic orientation. Based on the results of this investigation, a method of the grain selection with a desired azimuthal orientation is proposed.

Plastic scintillators are often used as detectors in High Energy Physics (HEP), but have insufficient radiation hardness. Organization of better light collection inside a single detector may prolong operation life of scintillators. A finger-strip plastic scintillator option has many advantages to keep the excellent detector performance at high luminosity. Measurements assigned to show an advantage of a stripped detector vs. the un-stripped one in the range of increased absorbed doses and the smallest dose rates have been performed. This method has proved to be a good upgrade strategy.

The luminescence, absorption, and luminescence excitation spectra of complexes cis-[Ru(bpy)2(L)(NO2)]+ [bpy = 2,2′-bipyridyl, L = pyridine, 4-aminopyridine, 4-dimethylaminopyridine, 4-picoline, isonicotinamide, or 4,4′-bipyridyl] in alcoholic (4 : 1 EtOH–MeOH) solutions are studied at 77 K. A linear correlation is established between the energy of the lowest electronically excited metal-toligand charge transfer state d π(Ru) → π*(bpy) of the complexes and the pKa parameter of the free 4-substituted pyridines used as ligands L. The B3LYP/[6-31G(d)+LanL2DZ(Ru)] hybrid density functional method is used to optimize the geometry of complexes and calculate their electronic structure and the charge distribution on the atoms of the nearest environment of ruthenium(II) ions. It is shown that there exists a mutually unambiguous correspondence between the charge on the nitrogen atom of ligands L coordinated in the complex and the pK a parameter of ligands. The calculated energies of the electronically excited metal-to-ligand charge transfer states of complexes linearly (correlation coefficient 0.99) depend on the charge on the nitrogen atom of ligands L, which completely agrees with the experimental data.

The structure of the condensation products of 2-hydroxybenzohydrazide, 2-aminobenzohydrazide, and N-methyl-N-(2-aminobenzo) hydrazide with a series of aldoses (L-arabinose, D-ribose, L- rhamnose, D-galactose, D-glucose, and D-mannose) was studied by 1H- an...

The structure of the condensation products of thiobenzohydrazide, 2-sulfanylacetohydrazide, 3-sulfanylpropiohydrazide, and 2-sulfanylbenzohydrazide with a series of aldoses (L-arabinose, D-ribose, L-rhamnose, D-galactose, D-glucose, and D-mannose) was studied by 1H- and 13C-NMR spectroscopy.

Requirements for higher-performance on-board control systems and instruments applied in a variety of small-scale moving objects results in the necessity to develop micromechanical sensors – small, lightweight, energy-efficient and, at the same time, offering high-reliability performance and easy-to-use. Development of such MEMS will require – in its turn – controlling parameters which determine the quality of the sensor. These strictly-controlled parameters will most immediately influence the desired outcomes and underlie more efficient use of resources to achieve the desired aims. The problem discussed has already been studied by many scientists. MEMS have been and are being developed by both Russia-based and foreign companies like Honeywell International Inc., Analog Devices Inc., JSC Radar MMS, Temp-Avia plc., to name a few.

Optically pure (2S,4S)-2-alkyl-6-oxo-3-(phenylcarbamothioyl)hexahydropyrimidine-4-carboxylic acids have been synthesized from natural L-asparagine, commercially available aldehydes, and phenyl isothiocyanate. The product structure was confirmed by 1H and 13C NMR data.

Using the numerical simulation in the CA-FE module of the ProCAST simulation program, a systematic investigation of competitive growth of grains in a thin plate has been performed over a wide range of values of the temperature gradient and solidification rate. It has been established that the result of the simulation in the case of converging grains depends on the only parameter, i.e., the ratio of the value of the overgrowth of the grain with the preferred orientation to the size of the cell of the computational grid. Thus, the size of the cell is an important adjusting parameter of the model and must be coordinated with the parameters of the dendritic structure under given growth conditions. The grain with the preferred orientation always displaces neighboring diverging grains. The converging grains are eliminated if their deviation from the vector of the temperature gradient exceeds 20°. At the smaller angles of deviation, the result of the competitive growth depends on the size of the computational cell and varies from their joint growth (at the cell size of 5 μm) to the displacement of grains with the preferred orientation (at the cell size of 20 μm). However, all of the results of the simulation agree with the experimental data available in the literature. For the efficient selection of grains with the preferred orientation, regimes with a low temperature gradient and high growth rate are favorable.

Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.

The natural amino acid L-cysteine, commercially available aldehydes, and 3-(acetylsulfanyl)propionyl chloride were used for the synthesis of 2-substituted (2R,4R)-3-(3-mercaptopropionyl)thiazolidine-4-carboxylic acids, potential antihypertensive drugs with angiotensin converting enzyme inhibiting action.

Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohydropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.

The luminescence spectra of cis-[Ru(bpy)2(L)Cl]+ (bpy is 2,2′-bipyridyl; L is pyrazine, pyridine, 4-amino-pyridine, 4-picolin, isonicotinamide, 4-cyanopyridine, or 4,4′bipyridyl) complexes are studied in alcoholic (4: 1 EtOH-MeOH) solutions at 77 K. A linear correlation is found between the energy of the lowest electronically excited metal-to-ligand charge transfer (3MLCT) state dπ(Ru) → π* (bpy) and the parameter pKa of the free 4-substituted pyridines and pyrazine used as ligands L. The [B3LYP/6-31G + LanL2DZ(Ru)] hybrid method of the density functional theory is used to optimize the geometry of complexes and calculate their electronic structure and the charge distribution on the atoms of the nearest environment of the ruthenium ion. It is shown that there exists a linear unambiguous correlation between the negative charge on the nitrogen atom (qNL) of ligands L coordinated in the complex and the parameters pKa of free ligands. The calculated energies of 3MLCT excited states almost linearly (correlation coefficient 0.958) depend on the charge qNL, which completely agrees with experimental data.

The results of testing a detector based on a thick gas electron multiplier (GEM) are presented. Impact of the TGEM dielectric charging on detector physical parameters is assessed based on simulation and experimental results. The further development of the detector—TGEM with resistive coating was constructed and tested. The test results are presented and compared to a standard thick GEM.

Changes in the structure of microperiphyton and zooplankton communities in the presence of hydrophytes Ceratophyllum demersum L. and Utricularia vulgaris L. have been studied. In experimental ecosystems with hydrophytes, the ratio of autotrophic to heterotrophic organisms and the abundance of Sarcomastigophora decreased while the number of infusorians in microperiphyton increased. The abundance of Rotifera and crustaceans of fam. Chydoridae increased significantly in zooplankton. Specific features of the structure of two communities depending on a plant species were noted. It was revealed that the species composition and abundance of microperiphyton and zooplankton in overgrowths of hydrophytes are closely related. Algae not consumed by zooplankters dominate in microperiphyton. The structure and ratio of heterotrophic organisms depended mainly on the abundance of zoophagous cyclops.

The influence of the submerged plants Ceratophyllum demersum L. and Elodea canadensis Michx. and the floating plant Hydrocharis morsus-ranae L. on the species composition and quantitative parameters of a zooplankton community was studied experimentally. Among submerged vegetation, the development of the predaceous calanid Heterocope saliens Lilljeborg was suppressed. An increase in the number of zooplankter species was observed in all experimental ecosystems with hydrophytes. The species similarity of zooplankton was higher between communities with plants of the same ecological group than with plants of different groups. The highest average zooplankton biomass, as determined by the abundance of Daphnia longispina O.F. Muller and Simocephalus vetulus (O.F. Muller), was observed in experiments with Elodea. The highest average abundance over the experimental period was recorded among Ceratophyllum, where the abundance of Rotifera, chydorids, and copepods common in hydrophyte beds was higher than in other versions of the experiment.

We studied the spectral-luminescent characteristics of the luminescence of mixed-ligand polypyridine-phosphine complexes of ruthenium(II) cis-[Ru(bpy)2(PPh3)X](BF4)n with ligands 2,2′-bipyridyl (bpy) and triphenylphosphine (PPh3) and X = Cl−, Br−, CN−, NO2−, NH3, MeCN, pyridine (py), 4-aminopyridine (pyNH2), and 4,4′-bipyridyl (4,4′-bpy) in a 4: 1 EtOH-MeOH alcoholic mixture at 77 K. The radiative and nonradiative deactivation rate constants of the lowest electronically excited state of the complexes are determined. We find that triphenylphosphine has a greater effect on the photophysical characteristics of ruthenium(II) complexes compared to π-acceptor strong-field ligands, such as MeCN, CN−, and NO2−. At the same time, the characteristics of complexes cis-[Ru(bpy)2(PPh3)X]n+ considerably depend on the nature of the second monodentate ligand X, which is coordinated to ruthenium(II), and correlate with its position in the spectrochemical series of ligands.

The products of the condensation of aliphatic aldehydes with N-(2-aminobenzoyl)-N-methylhydrazine exist in DMSO-d6 solution as tautomeric mixtures of linear aldohydrazone and cyclic benzo-1,3,4-triazepine forms. The linear tautomer predominates for 2-aminobenzoyl-N-methylhydrazones of aromatic aldehydes. A tautomeric equilibrium is observed in DMSO-d6 for the products of the condensation of the hydrazide of 2-aminobenzoic acid with a series of aldoses. This equilibrium exists between α,β-isomeric pyranose forms and the open aldosohydrazone form. Isomeric conversion to the seven-membered benzo-1,3,4-triazepine form is observed for the products of the condensation of aldoses with N-(2-aminobenzoyl)-N-methylhydrazine.

It has been shown by 1H NMR spectroscopy that 2-mercaptobenzoylhydrazones of aromatic aldehydes 2-HSC6H4CONHN=CHC6H4X (X = 4-NO2, 3-NO2, 4-Br, H, 4-Me, 4-MeO, 4-Me2N) exist in DMSO-d6 solution as tautomeric mixtures of linear and cyclic benzo-1,3,4-thiadiazepine forms. The linear hydrazone form is represented by (E,Z′)-conformational isomers, differing in the disposition relative to the amide C–N bond. It was shown that the logarithm of the tautomeric equilibrium constant K T correlates with the σ-constants of the substituents in the aromatic nucleus.

The formation of DNA complexes with polycations of different structure (homopolymers: N,N-dimethylaminoethyl and methylsulfate salt of N,N,N-trimethylaminoethylmethacrylate, along with a copolymer of N,N-dimethylaminoethyl methacrylate with N-methacryloylaminoglucose) in water-salt solutions, was studied by the method of static and dynamic light scattering. It was shown that, depending on the value of ϕ = [mol polycation]/[mole of DNA], complexes of different structure are formed: in field ϕ 6 in the presence of a large excess of polycations, loose structures are formed. The extreme dependence of the molecular weight of formed supramolecular structures on the values of ϕ was established.

Condensation products of aliphatic aldehydes with 3-sulfanylpropionic acid hydrazide exist in solution as mixtures of linear hydrazone and cyclic 1,3,4-thiadiazepine tautomers. Hydrazones derived from 3-sulfanylpropionic acid hydrazide and aromatic aldehydes and ketones have mostly linear structures of different stereoisomers arising from Z-E isomerism with respect to the double C=N bond and restricted rotation about the C(O)-N bond. Condensation products of 3-sulfanylpropionohydrazide with a series of aldoses give rise to ring-chain-ring tautomeric equilibrium between α,β-isomeric pyranose structures, open-chain aldose hydrazone tautomer, and two diastereoisomeric seven-membered cyclic 1,3,4-thiadiazepine forms.

The isomeric transition of 2-aminobenzoylhydrazones of aliphatic aldehydes 2-H2NC6H4CONHN=CHAlk (Alk = Me, Et, Pr, Bu) in chloroform-d1 solution into the cyclic 1,2-dihydroquinazolin-4-one form has been studied. The structure of the obtained compounds was demonstrated by methods of 1H and 13C NMR spectroscopy.