Leonid Fershtat

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• PhD Dr.Sci. in Organic Chemistry
• Principal Investigator at N.D. Zelinsky Institute of Organic Chemistry

A novel one‐pot cascade method for the assembly of valuable NO‐donor azasydnone scaffold has been developed. The construction strategy involves a diazotization/azo coupling/elimination/double rearrangement cascade sequence of readily available amines. The current protocol enables the generation of a diverse array of azasydnones, including previousl...

This Review covers the synthesis and performance of the most promising 1,2,5‐oxadiazole‐based high‐energy density materials (HEDMs). These materials comprise a 1,2,5‐oxadiazole subunit as a key structural motif linked to various acyclic explosophoric groups or to nitrogen‐rich and nitrogen‐oxygen azoles: 1,2,4‐triazole, tetrazole, 1,2,4‐ and 1,3,4‐...

Energetic materials science is undergoing a global renaissance aiming to reach an ideal combination between reliable synthetic strategies, high performance and acceptable molecular stabilities. In this work, design and synthesis of novel energetic non-hydrogen furoxan assemblies has been successfully realized. Fine tunability of molecular compositi...

The development of liquid energetic fuels with improved properties is an important topic in space propulsion technologies. In this manuscript, a series of energetic ionic liquids incorporating a 1,2,5‐oxadiazole ring and nitrate, dicyanamide or dinitramide anion was synthesized and their physicochemical properties were evaluated. The synthesized co...

The preparation of multipurpose high-energy materials for space technologies remains a challenging task and such materials usually require special precautions and fine tunability of their functional properties. To unveil new opportunities en route to high-performance energetic materials, novel potential melt-castable explosives and energetic plasti...

Background: Nitric oxide (NO) has been linked to the pathogenesis of asbestos-related pleural diseases, including an extremely aggressive cancer called malignant pleural mesothelioma (MPM). Given that MPM cells are characterized by a higher expression of NO synthases and elevated NO production relative to normal cells, the use of NO-donor compounds...

Novel energetic materials (EM) often combine two intrinsically counter trends, viz., a high energy density and mediocre safety parameters, like thermal stability and sensitivity toward mechanical stimuli. A rational design of promising EMs requires a proper understanding of their thermal stability at both macroscopic and molecular levels. In the pr...

For the first time, structure of the 3-cyano-4-azido-1,2,5-oxadiazole 2-oxide (3-cyano-4-azidofuroxan, CAziFO) molecule in the gas phase was studied by means of gas electron diffraction (GED) and quantum chemical calculations. Equilibrium parameters of the molecule were found. The data obtained were compared with those of related compounds studied...

A key goal of organic chemistry is to develop new principles for the control of reactions, which can be used to create promising materials demanded in all fields of scientific research and industry. This review is an overview of the scientific advances, which have been made by the N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy...

Design and synthesis of new energetic materials retains its urgency in chemistry and materials science. Herein, rational construction and regioselective synthesis of a series of energetic compounds comprising of a methylene‐bridged combination of 1,2,5‐oxadiazole and nitrogen‐rich azoles (1,2,4‐triazole and tetrazole) enriched with additional explo...

The decomposition rates of diphenylfuroxane and a number of 4-nitro-3-alkyl-furoxanes in dilute solutions were measured by manometric and calorimetric methods. In no case, an increase in the reaction rate was detected with an increase in the polarity of the solvent, which corresponds to the absence of an increase in the dipole moment of the molecul...

Synthetic electrochemistry may establish direct routes to a preparation of a plethora of organic substances, which are hardly accessible by conventional experimental techniques. Herein, we present an electrochemically‐driven method for an assembly of a broad range of rare heterocyclic mesoionic entities –1,2,3‐triazole 1‐imines. These nitrogen hete...

A straightforward protocol for the synthesis of a previously unknown [1,2,5]oxadiazolo[3,4- d ][1,2,3]triazin-7(6 H )-one heterocyclic system was developed. The described approach is based on tandem diazotization/azo coupling reactions of (1,2,5-oxadiazolyl)carboxamide derivatives bearing both aromatic and aliphatic substituents. The NO-donor abili...

Впервые с помощью метода газовой электронографии (ГЭ) и квантово-химических расчётов исследована структура молекулы 3-циано-4-амино-1,2,5-оксадиазол-2-оксида (3-циано-4-аминофуроксана, ЦАФО) в газовой фазе и найдены равновесные параметры исследуемой молекулы. Проведено сравнение полученных данных с таковыми у родственных соединений, исследованных с...

Electrochemistry became a unique and powerful tool for the preparation of a plethora of valuable chemical species including functional materials, drug candidates and clinically approved pharmaceuticals. Organic electrosynthesis well satisfies main goals of green chemistry development and is considered as one of the useful approaches toward the crea...

The chemistry of heterocyclic compounds has traditionally been and remains a bright area of chemical science in Russia. This is due to the fact that many heterocycles find the widest application. These compounds are the key structural fragments of most drugs, plant protection agents. Many natural compounds are also derivatives of heterocycles. At p...

Mechanical stress is an important trigger of reactions in chemicals. Historically, the standard testing protocols for impact and friction sensitivity have been developed mainly for energetic materials and explosives. As a result, the structure− mechanical safety data is available for common explosives and is constantly reported for newly synthesize...

Energetic materials are important class of functional compounds that combine the beauty of extreme high-energy chemistry with rigorous constraints on safety and performance. As a result, the development of energetic materials is a challenging process that require the best of computational, chemical synthesis, and material design techniques. This re...

New promising energetic materials comprised of 1,2,4-triazole and furoxan rings and bearing explosophoric nitro group were rationally designed and synthesized. All newly prepared compounds were thoroughly characterized and their physicochemical properties were estimated. In the newly synthesized series, (1,2,4-triazolyl)furoxan 4 is completely inse...

The main aspects of the reactivity of 2-aminopyridine N-oxides and similar heterocyclic systems are discussed. Literature data are systematized based on the types of transformations considered with a focus on the major advantages and disadvantages of each synthetic method. The possibility to synthesize previously inaccessible functionally substitut...

The possibility to estimate the electron population of Bader’s interatomic surfaces using the electron density function values at the (3, −1) critical points is discussed taking the results of quantum chemical calculations of three model sets of isolated atomic aggregates as examples. A relevant method based on the approximation of normal distribut...

Исследования высокоэнергетических материалов на основе полиазот- и азоткислородсодержащих гетероциклов являются одним из важнейших и актуальных современных междисциплинарных научных направлений, находящихся на стыке органической и физической химии и материаловедения. В ряду таких гетероциклов важным "строительным блоком" для получения новых энергое...

This work reconsiders the known condensation reaction of 1,2-diketones with arylhydrazines in the synthesis of the corresponding bishydrazones. It was shown that the reaction outcome significantly depends on the nature of the substituent of the aromatic ring of arylhydrazine. In addition, representatives of unsymmetrically substituted bishydrazones...

Modeling of the structure of molecules and simulation of crystal structure followed by the calculation of the enthalpies of formation for 21 salts of three high-energy tetrazole 1N-oxides: 5-nitro-1-hydroxy-1H-tetrazole 1a-1g,...

The synthesis verification of 3-amino-4-azido-1,2,5-oxadiazole and its structural characterization (IR, NMR, X-Ray, elemental analysis) are reported. Its thermal behavior (TG-DSC), standard enthalpy of formation, sensitivity to mechanical stimuli, detonation parameters were studied. Our study unveils wide application perspectives of 3-amino-4-azido...

A facile and efficient method for the regioselective [3 + 2] cycloaddition of 4-azidofuroxans to 1-dimethylamino-2-nitroethylene under p-TSA catalysis affording (4-nitro-1,2,3-triazolyl)furoxans was developed. This transformation is believed to proceed via eliminative azide-olefin cycloaddition resulting in its complete regioselectivity. The develo...

An optimized synthetic protocol toward the assembly of Kuhn verdazyls based on an azo coupling of arenediazonium salts with readily available hydrazones followed by the base-mediated cyclization of in situ formed formazans with formalin was developed. The scope and limitations of the presented method were revealed. Some new mechanistic insights on...

In recent decade, significant achievements in research on nanoenergetic materials have been realized. The principle of nanoenergetics is the enhancement of the specific surface area and intimacy with chemical components to improve the reaction rate while reducing the ignition delay at an acceptable level of safety. As a rule, nanoenergetic material...

A direct approach toward the construction of furoxan-sydnone imine double NO-donors involving the NOBF4-mediated nitrosation-cyclization sequence of α-amino nitriles as a key synthetic step was developed. The described protocol excludes the formation of carcinogenic N-nitrosamines, operates broad substrate scope and enables a preparation of fully s...

Electrochemical synthesis became one of the emerging and powerful tools to create novel state-of-the-art strategies for an assembly of complex organic molecules. However, electrochemically-induced N-N bond forming reactions still remain...

A regioselective approach toward the synthesis of a set of new (2‐vinyltetrazolyl)furoxans as potential energetic monomers has been realized. All target energetic materials were thoroughly characterized by spectral and analytical methods. Moreover, crystal structures of two representative heterocyclic systems were studied by single‐crystal X‐ray di...

The performance of an energetic material in a final composition and device is not solely dependent on the performance of the discrete energetic molecules within. While one major route of improving energetic performance is to increase the performance of the discrete molecules within, the non‐energetic materials mixed with the energetic molecule in t...

Methods for the synthesis of two types of isomeric dispirocompounds based on imidazothiazolotriazine and pyrrolidineoxindole, differing in the structure of imidazothiazolotriazine fragment, namely, linear dispiro[imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazine-6,3′-pyrrolidine- 4′,3″-indolines] and angular dispiro[imidazo[4,5-e]thiazolo[2,3-c][1,2,4]t...

Novel synthetic strategies toward construction and functionalization of nitrogen-rich energetic compounds bearing at least one heterocyclic N-oxide scaffold are briefly overviewed. The present focus review summarizes main recent advances (published in the period 2017–2022) in the chemistry of five- and six-membered heterocyclic N-oxides as well as...

Cocrystal design is an important and well-developed approach in the pharmaceutical industry. Energetic materials can be thought of as unique and challenging objects for cocrystal engineering since abundant explosophoric functionalities prevent exploiting common supramolecular synthons. Screening of cocrystal formation using thermal analysis methods...

Nitrogen-rich energetic materials comprised of a combination of several heterocyclic subunits retain their leading position in the field of materials science. In this regard, a preparation of novel high-energy materials with balanced set of physicochemical properties is highly desired. Herein, we report the synthesis of a new series of energetic sa...

Energetic materials constitute one of the most important subtypes of functional materials used for various applications. A promising approach for the construction of novel thermally stable high-energy materials is based on an assembly of polynitrogen biheterocyclic scaffolds. Herein, we report on the design and synthesis of a new series of high-nit...

In recent years, the development of novel advanced energetic materials has significantly shifted toward nitrogen heterocyclic derivatives, which demonstrate a great potential for multipurpose application patterns. Among known heterocycles tetrazine ring is a well-known structural scaffold used in a preparation of various high-energy materials. The...

Nitrogen-oxygen organic materials constitute an important family of multipurpose high-energy materials. However, the preparation of energetic boosters and oxidizers for various civil and space technologies remains a challenging task and such materials usually require special precautions and fine tunability of their functional properties. To find a...

Functionally substituted 1,2,5-oxadiazole 2-oxides (furoxans) are important pharmaceutical scaffolds used for the preparation of various pharmacologically active substances. Furoxans bearing hydrazone functionality are considered as promising drug candidates for the treatment of neglected diseases. However, pharmacologically oriented hydrazones der...

Two novel representatives of energetic (1,2,4-triazolyl)furoxans were prepared from the readily available (furoxanyl)amidrazones. Synthesized compounds were thoroughly characterized with IR and multinuclear NMR spectroscopy, elemental analysis and X-ray diffraction data. Analysis of structural features supported by quantum-chemical calculations rev...

An efficient synthesis of N- and S-substituted arylglyoximes via one-pot transformations of available monoarylfuroxans was developed. The proposed approach includes furoxan ring cleavage followed by the generation of α-oximinoacetonitrile oxides which further add N- and S-nucleophiles.

An approach for the synthesis of the first representatives of 3,5-difuroxanyl-1,6-di-hydro-1,2,4-triazines based on the reaction of (furoxanyl)amidrazones with 4-amino-3-bromoacetylfuroxan under mild conditions was proposed. It was shown that the reaction proceeds via initial alkylation of the starting amidrazones with bromoacetylfuroxan followed b...

The review presents the general methods for the formation of the framework of 1,4-dihydro- 1,2,4-benzotriazin-4-yl radicals (Blatter radicals) and their polycyclic derivatives published over the past 7 years. The target heterocyclic structures are formed by a number of approaches such as oxidative cyclization of amidrazones, addition of organolithi...

A series of novel 1,4-dihydrobenzo[1,2,4][e]triazines bearing an acetyl or ester moiety as a functional group at the C(3) atom of the 1,2,4-triazine ring were synthesized. The synthetic protocol is based on an oxidative cyclization of functionally substituted amidrazones in the presence of DBU and Pd/C. It was found that the developed approach is s...

A method for the introduction of the N,N-dimethylformamidine protective group in a series of six-membered 2-aminohetarene N-oxides was developed. It was shown that 2-amino derivatives of N-oxides of various six-membered heterocycles (pyridines, pyrimidines, pyrazines, tetrazines) successfully enter the reaction. The stability of the N,N-dimethylfor...

A series of novel, structurally diverse 1,2,4- and 1,2,5-oxadi- azole assemblies was synthesized from readily available furoxanyl precursors. Experimentally determined physico-chemical properties and calculated detonation parameters showed an application potential of the prepared nitrogen-oxygen molecular systems as promising energetic materials.

Furoxan derivatives enriched with explosophoric functionalities are promising compounds in the preparation of novel energetic materials. Herein, a previously unknown potassium (3-methyl-2-oxido-1,2,5-oxadiazol-4-yl)dinitromethanide (also referred to as potassium 4-dinitromethyl-3-methylfuroxanate) was synthesized via tandem nitration-reduction reac...

Analysis of thermal behavior of liquids is often accompanied by vaporization. In an extreme case, the calorimetric (DSC) experiment reveals the only endothermic evaporation instead of the more valuable thermal decomposition. 3-Methylfuroxan (MMF) is an energetic monosubstituted 1,2,5-oxadiazole N-oxide that shows the above behavior. We investigate...

A general method for the synthesis of a series of previously unknown N-(heteroaryl)- and N-(aryl)aminotetrazoles through the tandem electrocyclization/hydrolysis of azidohydrazones was accomplished. The described protocol was suitable for a wide array of the target N-substituted aminotetrazoles which were prepared in good to high yields under smoot...

Novel efficient synthetic strategies, including green methodologies, to basic and perspective high-energy density compounds, bearing active oxygen sources (C-, N- and O-nitro groups and N-oxide fragments) and high-enthalpy polynitrogen heterocycles, are briefly overviewed. Recently developed synthetic approaches to nitro group-free hypergolic ionic...

Mechanical and thermal hazards are critical for chemical compounds. Foremost, the design of novel energetic materials that are stable, insensitive, but have a detonation performance superior to in-service materials is of great interest. However, a single source of safety data for hazardous materials with explosophoric functionalities is still missi...

A series of novel energetic materials comprising of azo‐bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high‐energy materials were thoroughly characterized by IR and multinuclear NMR (¹H, ¹³C, ¹⁴N) spectroscopy, high‐resolution mass spectrometry, elemental analysis, and differential scanning calor...

Nitric oxide (NO) is a key signaling molecule that acts in various physiological processes such as cellular metabolism, vasodilation and transmission of nerve impulses. A wide number of vascular diseases as well as various immune and neurodegenerative disorders were found to be directly associated with a disruption of NO production in living organi...

A regioselective method for an assembly of pharmacologically relevant fully substituted furoxans and isoxazoles using the ring distortion diversity‐oriented approach through the one‐pot ring cleavage/nucleophilic addition/oxidation cascade of monosubstituted furoxans was developed. The described synthetic strategy is highly regioselective and provi...

A series of highly energetic nitrogen-rich salts comprised of a 5-(trinitromethyl)tetrazolate anion and high-nitrogen cations was synthesized by simple and efficient chemical routes from readily available commercial reagents. These energetic materials were fully characterized by IR and multinuclear NMR (1H, 13C, 14N) spectroscopy, elemental analysi...

A series of biheterocyclic assemblies comprising of 1,2,5‐oxadiazole and azasydnone scaffolds were synthesized and biologically evaluated as novel NO‐donor and antiplatelet agents. Depending on functional substituents at the biheterocyclic core, all studied compounds demonstrated good NO‐donor profiles releasing NO in a wide range of concentrations...

Five-membered heterocyclic N-oxides attract special attention due to their significant potential applications in medicinal chemistry and advanced materials science. In this regard, novel methods for their synthesis and functionalization are in constant demand. In this short review, recent state-of-the-art achievements in the chemistry of isoxazolin...

Using quantum chemical methods and the original technique based on atom-atom potential methods, the molecular and crystal structure simulation of all possible structural forms of nitrodiaziridines were carried out. The possible pathways of thermal decomposition of nitrodiaziridines were modeled, and the most stable forms were identified. Thermodyna...

In recent years, the development of novel advanced high-energy density materials has significantly shifted toward nitrogen-containing heterocyclic derivatives, which demonstrate a great potential for multipurpose application patterns. Among known heterocycles hydroxytetrazole is of special importance due to its high nitrogen-oxygen content and a po...

A simple and effective protocol for the synthesis of 2H-pyrazolo[3,4-d]pyridazine 5,6-dioxides includes a transformation of accessible 3,4-diacetyl-5-methyl-1H-pyrazoles into the corresponding 1,4-dioximes followed by their N2O4- mediated oxidative cyclization. All transformations proceed under mild conditions in good to high yields. According to t...

In the present work, we studied in detail the thermochemistry, thermal stability, mechanical sensitivity, and detonation performance for 20 nitro-, cyano-, and methyl derivatives of 1,2,5-oxadiazole-2-oxide (furoxan), along with their bis-derivatives. For all species studied, we also determined the reliable values of the gas-phase formation enthalp...

A straightforward synthesis of a series of previously unknown N-(1,2,5-oxadiazolyl)hydrazones through the diazotization/reduction/condensation cascade of amino-1,2,5-oxadiazoles was accomplished. The described protocol was suitable for a wide array of target hydrazones, which were prepared in good to high yields under smooth reaction conditions wit...

The Front Cover illustrates the ability of arylazofuroxans to switch between two isomers, a process easily tuned by visible light or elevated temperature, and which significantly affects NO‐donor ability. More information can be found in the Article by Leonid L. Fershtat and co‐workers.

The front cover artwork is provided by the Laboratory of Nitrogen‐Containing Compounds at the Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences (ZIOC RAS; Russia). The image shows a metronome which symbolizes the ability of arylazofuroxans to switch between two isomers with significantly different NO donor ability. The swit...

A series of novel molecular photoswitches incorporating an aryldiazenyl moiety linked to a 1,2,5‐oxadiazole (furazan) or 1,2,5‐oxadiazole 2‐oxide (furoxan) subunit was synthesized by a simple and step‐economic chemical route. Upon visible light irradiation, (E)‐arylazo‐1,2,5‐oxadiazoles underwent photoisomerization to the corresponding (Z)‐isomers...

Several energy-rich bifuroxans incorporating nitro and azido functionalities have been synthesized and thoroughly characterized by IR and multinuclear NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction and differential scanning calorimetry. N-oxide regiochemistry was employed to design the tunable azido(nitro)bifuroxans with dif...

The equilibrium molecular structures of the isomeric 3-methyl-4-nitro- and 4-methyl-3-nitrofuroxans have been determined for the first time by gas-phase electron diffraction (GED) supported by coupled cluster calculations up to CCSD(T)/cc-pVTZ level of theory, in frame of dynamic model with relaxation of all structural parameters. The best fit of t...

A tandem method of synthesis of 3-hetaryl-4-nitrofuroxans was developed based on the one-pot sequence of thermolysis of 4-nitrofuroxannitrolic acid to the corresponding 4-nitro-3-furoxancarbonitrile oxide and [3+2] cycloaddition of the latter to acetylenes and olefins. It was established that the synthesized 3-(isoxazol-3-yl)- and 3-(isoxazolin-3-y...

A novel method for the synthesis of a diverse series of functionally substituted five-membered heterocyclic compounds via atom-economic, regio-, and diastereoselective one-pot reaction cascade was developed. This approach involves a ring opening in 4-arylfuroxans to α-oximinoarylacetonitrile oxides followed by [3+2] cycloaddition to various dipolar...

A novel one-pot approach for the synthesis of 1,2,4- and 1,2,5-oxadiazole ring assemblies has been developed. The synthetic strategy involves the condensation of furoxanyl amidoximes with aldehydes and subsequent iodine-mediated oxidation of the intermediate 1,2,4-oxadiazolines. The analogous reaction of 4-aminofuroxanyl-3-carboxamidoxime results n...

The review is devoted to modern trends in the chemistry of nitrogen-, oxygen-and sulfur-containing monocyclic, polynuclear and benzo(hetero)annulated heterocyclic compounds. Methods for the synthesis and chemical reactivity of furazan, furoxan, thiazole, thiadiazole, dithiazole, thiophene, glycoluril, imidazotriazine, diaziridine and other heterocy...

1,2,5-Oxadiazoles (furazans) and 1,2,5-oxadiazole 2-oxides (furoxans) as well as their benzannulated derivatives (benzo[c][1,2,5]oxadiazoles and benzo[c][1,2,5]oxadiazole 1-oxides) are a widely known subclass of heterocycles. 1,2,5-Oxadiazoles exhibit a unique set of properties that has led to their use in the design of pharmacologically active and...

In this review article, we provide general information on the known methods for directed synthesis of 3- and 4-aminofuroxans, as well as analyze the main aspects of their reactivity. Methods for regio- and chemoselective transformations of aminofuroxans are considered in detail, including both classical reactions involving oxidation, acylation, and...

A new approach for the synthesis and reactivity of the 1,2,5‐oxadiazolyl diazonium salts is represented. A simple and direct protocol to previously inaccessible furoxanyl and furazanyl diazonium salts was developed for the first time. Azo coupling reactions of thus obtained diazonium salts with a series of structurally diverse CH‐acids have been al...

Crystallization of different biological targets and pharmaceuticals from ionic liquids (ILs) could result in previously unknown polymorph modifications. Crystallization of high energy materials (HEMs) from ILs has not been studied so far. This paper is devoted to the first attempts to crystallize a highly energetic compound – 2,4,6,8,10,12-hexanitr...

A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen‐rich cations were synthesized by simple, efficient, and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) spectroscopy, elemental analysis...

Hetarylfuroxans (4-(2-methylpyridin-5-yloxy)-3-phenylfuroxan (1), bis(1,2,4-oxadiazol- 3-yl)furoxan (2), and 4-amino-3-(indenotriazin-3-yl)furoxan (3)) exhibit in vitro cytotoxic activity against chronic myeloid leukemia K562 cells. All studied furoxans induce apoptosis in K562 cells. The experiments with activation of caspases-3 and -7 showed that...

A series of functionalized furoxans was synthesized, and their effect on the platelet aggregation was estimated using a set of inducers. New hybrid structures comprising the furoxan ring and glycolic or acetylsalicylic acid motifs effectively inhibit aggregate formation induced by adenosine diphosphate and adrenaline. Studies of their NO-donor abil...

The effective and regioselective synthesis of new (2-hydrazinylthiazol-4-yl)furoxan hydrobromides based on the condensation of (bromoacetyl)furoxans with thiosemicarbazide has been developed. The cytotoxic activity of their derivatives (with hydrazone, 4-thiazolo[2.3-c][1,2,4]triazole or pyrrole moieties) against two human cancer cell lines (A549,...