C Atoms Research Articles

Creating a Defined Chirality in Amino Acids and Cyclic Dipeptides by Photochemical Deracemization.

2,5-Diketopiperazines are cyclic dipeptides displaying a wide range of applications. Their enantioselective preparation has now been found possible from the respective racemates by a photochemical deracemization (53 examples, 74% to quantitative yield, 71-99% ee). A chiral benzophenone catalyst in concert with irradiation at λ= 366 nm enables to establish the configuration at the stereogenic carbon atom C6 at will. If other stereogenic centers are present in the diketopiperazines they remain unaffected and a stereochemical editing is possible at a single position. Consecutive reactions, including the conversion into N-aryl or N-alkyl amino acids or the reduction to piperazines, occur without compromising the newly created stereogenic center. Transient absorption spectroscopy revealed that the benzophenone catalyst processes one enantiomer of the 2,5-diketopiperazines preferentially and enables a reversible hydrogen atom transfer that is responsible for the deracemization process. The remarkably long lifetime of the protonated ketyl radical implies a yet unprecedented mode of action.

Studies of the Chemical Reactivity of a Series of Benzimidazolyl-Chalcone by Quantum Chemical Approaches

This theoretical chemical reactivity study was conducted using the Density Functional Theory (DFT) method at the B3LYP/6-311G(d,p) level of calculation. It involved a series of five (05) Benzimidazolyl-Chalcone (BZC) and allowed the prediction of the chemical reactivity of these compounds. The DFT global chemical reactivity descriptors (HOMO and LUMO energies, chemical hardness, energy, electronic chemical potential and electrophilicity) were examined to predict the relative stability and reactivity of BZCs. Thus BZC-4 which has a boundary orbital energy gap of ΔEgap = 3.650 eV is the most polarisable, most reactive, good nucleophile.and it is a soft molecule. The values of the global reactivity descriptors confirmed the high chemical reactivity of BZC-4. Local reactivity indices as well as dual descriptors were calculated to indicate the likely sites of electrophilic and nucleophilic attack of the different compounds studied. The analysis of the local indices and the dual descriptors revealed that the nitrogen heteroatom N13 is the preferential site of electrophilic attack and the carbon atom C1 should be the most reactive site with respect to a nucleophilic attack. the Hierarchical Ascending Classification analysis allowed us to group all five (5) compounds studied into three categories. The most active which are BZC-1 and BZC-5, the moderately active BZC-2, and the compounds BZC-3 and BZC-4, the least active. Moreover, this classification is consistent with the value of the Larvicide concentrations (LC100 (μg/mL)).
 Keywords : Benzimidazolyl-Chalcone (BZC), Global descriptors, Local descriptors, Dual descriptors

Exploring the Mechanism of the Intramolecular Diels-Alder Reaction of (2E,4Z,6Z)-2(allyloxy)cycloocta-2,4,6-trien-1-one Using Bonding Evolution Theory.

In the present work, the bond breaking/forming events along the intramolecular Diels-Alder (IMDA) reaction of (2E,4Z,6Z)-2(allyloxy)cycloocta-2,4,6-trien-1-one have been revealed within bonding evolution theory (BET) at the density functional theory level, using the M05-2X functional with the cc-pVTZ basis set. Prior to achieving this task, the energy profiles and stationary points at the potential energy surface (PES) have been characterized. The analysis of the results finds that this rearrangement can proceed along three alternative reaction pathways (a-c). Paths a and b involve two steps, while path c is a one-step process. The first step in path b is kinetically favored, and leads to the formation of an intermediate step, Int-b. Further evolution from Int-b leads mainly to 3-b1. However, 2 is the thermodynamically preferred product and is obtained at high temperatures, in agreement with the experimental observations. Regarding the BET analysis along path b, the breaking/forming process is described by four structural stability domains (SSDs) during the first step, which can be summarized as follows: (1) the breaking of the C-O bond with the transfer of its population to the lone pair (V(O)), (2) the reorganization of the electron density with the creation of two V(C) basins, and (3) the formation of a new C-C single bond via the merger of the two previous V(C) basins. Finally, the conversion of Int-b (via TS2-b1) occurs via the reorganization of the electron density during the first stage (the creation of different pseudoradical centers on the carbon atoms as a result of the depopulation of the C-C double bond involved in the formation of new single bonds), while the last stage corresponds to the non-concerted formation of the two new C-C bonds via the disappearance of the population of the four pseudoradical centers formed in the previous stage. On the other hand, along path a, the first step displays three SSDs, associated with the depopulation of the V(C2,C3) and V(C6,C7) basins, the appearance of the new monosynaptic basins V(C2) and V(C7), and finally the merging of these new monosynaptic basins through the creation of the C2-C7 single bond. The second step is described by a series of five SSDs, that account for the reorganization of the electron density within Int-a via the creation of four pseudoradical centers on the C12, C13, C3 and C6 carbon atoms. The last two SSDs deal with the formation of two C-C bonds via the merging of the monosynaptic basins formed in the previous domains.

Nucleophilic carbon-carbon bond formation by 1-En-3-ynes via zirconocene-η2-1-en-3-yne complexes

Nucleophilic reactions by the C1 atom of 1-en-3-ynes toward organic electrophiles such as ketones, nitriles and isocyanates, via their organozirconium species, were investigated.Zirconocene complexes of conjugated 1-en-3-ynes coordinating in a η2-fashion were prepared, and then reacted with ketones, nitriles and isocyanates to afford seven-membered intermediate organozirconium compounds via CC bond formation. The corresponding alcohols, ketones, pyrroles and amides were obtained after hydrolysis. The products were, in principle, the same as those obtained from five-membered zirconacycloallene complexes, which were prepared from low-valent zirconocene and 1-en-3-ynes in the absence of ancillary ligands. Because only a limited number of 1-en-3-ynes can form zirconacycloallenes in significant yields, the present study allows a wider scope of 1-en-3-ynes for this synthetically useful reaction.

Structural basis for the allosteric pathway of 4-amino-4-deoxychorismate synthase.

4-Amino-4-deoxychorismate synthase (ADCS), a chorismate-utilizing enzyme, is composed of two subunits: PabA and PabB. PabA is a glutamine amidotransferase that hydrolyzes glutamine into glutamate and ammonia. PabB is an aminodeoxychorismate synthase that converts chorismate to 4-amino-4-deoxychorismate (ADC) using the ammonia produced by PabA. ADCS functions under allosteric regulation between PabA and PabB. However, the allosteric mechanism remains unresolved because the structure of the PabA-PabB complex has not been determined. Here, the crystal structure and characterization of PapA from Streptomyces venezuelae (SvPapA), a bifunctional enzyme comprising the PabA and PabB domains, is reported. SvPapA forms a unique dimer in which PabA and PabB domains from different monomers complement each other and form an active structure. The chorismate-bound structure revealed that recognition of the C1 carboxyl group by Thr501 and Gly502 of the 498-PIKTG-502 motif in the PabB domain is essential for the catalytic Lys500 to reach the C2 atom, a reaction-initiation site. SvPapA demonstrated ADCS activity in the presence of Mg2+ when glutamate or NH+4 was used as the amino donor. The crystal structure indicated that the Mg2+-binding position changed depending on the binding of chorismate. In addition, significant structural changes were observed in the PabA domain depending on the presence or absence of chorismate. This study provides insights into the structural factors that are involved in the allosteric regulation of ADCS.

Analysis of the Structure, Thermal, and Molecular Dynamics of Organic-Inorganic Hybrid Crystal at Phases IV, III, II, and I: [NH2(CH3)2]2CdBr4.

A comprehensive understanding of the physicochemical properties of organic-inorganic hybrids is essential for their solid-state lighting applications. Therefore, a single crystal of [NH2(CH3)2]2CdBr4 was grown; the crystal structure was monoclinic, and the phase transition temperatures for the four phases IV, III, II, and I were 383 K (TC1), 417 K (TC2), and 427 K (TC3). Furthermore, the chemical shifts caused by the local field around 1H, 13C, 14N, and 113Cd changed continuously with temperature, especially near TC1, indicating that the local environment changes with temperature. Owing to the large change in 113Cd chemical shifts, the coordination geometry of Br around Cd in the CdBr4 tetrahedra changes near TC1. Therefore, it is proposed that Br plays a significant role in the N-H···Br hydrogen bond. Finally, the spin-lattice relaxation time T1ρ, representing the energy transfer around the 1H and 13C atoms of the cation, changed significantly with temperature. The activation energies obtained from the T1ρ results were two times larger at high temperatures than at low temperatures. This study provides an understanding of the fundamental properties of organic-inorganic hybrid compounds to broaden their applications.

Total Synthesis of (-)-5-Deoxyenterocin and Attempted Late-Stage Functionalization Reactions.

The first total synthesis of (-)-5-deoxyenterocin has been accomplished starting from pentane-1,3,5-triol (16 steps in the longest linear sequence, 0.2 % overall yield). (-)-Menthone served as the source of chirality to distinguish the enantiotopic hydroxymethyl groups of the substrate. Key steps of the synthesis include two aldol reactions to either end of the C5 -skeleton, a diastereoselective hydroxylation reaction and a biomimetic twofold intramolecular aldol reaction as the final step. Although this step suffered from geometrical constraints and was low yielding (10 %), enough synthetic material could be secured to substantiate the relative and absolute configuration of the natural product. Additional experiments were directed toward a C-H functionalization at carbon atom C5. Despite the fact that several protocols could be successfully applied to (3aR)-(+)-sclareolide as model substrate, (-)-5-deoxyenterocin withstood any selective functionalization.

Experimental Study of Thick Target Yield from the 13C(α,n0)16O Reaction

The thick target neutron spectra from the 13C(α,n0)16O reaction were measured for the energy range of 3.0 to 6.5 MeV at 10 angles in the laboratory angle interval of 0 to 150 deg. The thick target yield (TTY) was determined by integration of the neutron spectra over the neutron energy range corresponding to the 13C(α,n0)16O reaction followed by integration of the obtained angular distribution of the differential TTY over the solid angle 4π. The content of 13C atoms in the target was determined by ion beam analysis with accuracy of <1%. The obtained TTY values support the calculated ones based on the 16O(n,α0)13C reaction cross-section evaluation from the ENDF/B-VIII.0 library.

Quantum Chemical Study of the Cycloaddition Reaction of Tropone with 1,1-Diethoxyethene Catalyzed by B(C6F5)3 or BPh3.

Cycloaddition reaction of tropone with 1,1-diethoxyethene catalyzed by Lewis acid (LA), B(C6F5)3 or BPh3, was examined by using ωB97X-D-level density functional theory (DFT) calculations. In the absence of LA, the reaction proceeds in a stepwise fashion to form two chemical bonds, first between the C2 atom in tropone and the C2 atom in ethene and then between the C5 atom in the former and the C1 atom in the latter. When B(C6F5)3 is attached to the O atom in tropone, the C5 atom in tropone is attacked preferentially by the C1 atom in ethene in the second stage. The attack of the O atom in tropone is shown to be less likely; thus, the [4 + 2] addition is favored in the B(C6F5)3-catalyzed reaction. In contrast, the attack of the O atom in the BPh3-attached tropone to the C1 atom in ethene is preferred over the attack of the C5 atom, indicating that the [8 + 2] cycloaddition instead of the [4 + 2] cycloaddition proceeds in the BPh3-catalyzed reaction. Whether the C1 atom in ethene is attacked by C5 or by O in the second bond formation step is shown in this study to be governed mainly by the nucleophilicity of σ-lone pair electrons of the carbonyl O atom of tropone in the presence of LA. These results are consistent with the experiments reported by Li and Yamamoto.

An antioxidant polybenzimidazole with naphthalene group for high-temperature proton exchange membrane fuel cells

One significant challenge to the durability of HT-PEMFCs is the susceptibility of PBI HT-PEMs to electrophilic free radicals, such as ∙OH and ∙OOH. In this study, the development of a N-PBI membrane with low C2 electron cloud density was explored as a potential solution to achieve good oxidative stability of HT-PEMs. The physicochemical properties of PBI membranes before and after the Fenton test were studied in terms of chemical structure, molecular weight, mechanical properties, and thermal stability. The results indicate that incorporating naphthalene ring into the molecular structure of PBI significantly enhances its oxidative stability compared to P-PBI with high electron cloud density C2 atom and copolymerized P0.5-N0.5-PBI. In addition, with a saturated ADL of 12.9, the PA-doped N-PBI membrane achieves an acceptable compromise between mechanical properties and proton conductivity, thus resulting a H2/O2 fuel cell PPD of 625 mW/cm2 at 160 °C. This work presents a theoretical basis for pursuing PBI membranes with greater oxidative stability.

Understanding the Fate of the Banert Cascade of Propargylic Azides: Sigmatropic versus Prototropic Pathway.

The Banert cascade is an efficient synthetic strategy for obtaining 4,5-disubstituted 1,2,3-triazoles. The reaction can proceed via a sigmatropic or prototropic mechanism depending on the substrate and the conditions. In this work, the mechanisms of both pathways from propargylic azides with different electronic features were investigated using density functional theory, quantum theory of atoms in molecules, and natural bond orbital approaches. The calculated energy barriers were consistent with the experimental data. Three patterns of electron density distribution on the transition structures were observed, which reflected the behaviors of the reactants in the Banert cascade. The stronger conjugative effects were associated with lower/higher free activation energies of sigmatropic/prototropic reactions, respectively. A clear relationship between the accumulation of the charge at the C3 atom of propargylic azides with the energy barriers for prototropic reactions was found. Thus, the obtained results would allow the prediction of the reaction's course by evaluating reactants.

Preparation of 2-Nitrocacalol Acetate From a Sesquiterpene Isolated From Roots of Psacalium decompositum. Evaluation of α-Glucosidase and Acetylcholinesterase Inhibition

Objective To introduce a nitrogen atom into the structure of the cacalol acetate and to evaluate the change in its ability to inhibit enzymes of therapeutic importance such as α-glucosidase and acetylcholinesterase (AChE), which are targeted in the development of drugs for the treatment of diabetes and Alzheimer’s disease (AD), respectively. Methods Cacalol acetate was obtained by subjecting the hexane and ethyl acetate extracts from the roots of Psacalium decompositum to acetylation conditions. Subsequently, the cacalol acetate was brought under nitration conditions using cerium (IV) ammonium nitrate and acetic anhydride to obtain 2-nitrocacalol acetate; this compound was characterized by nuclear magnetic resonance, mass spectrometry, and X-ray diffraction techniques. Additionally, the inhibitory activity of the ethyl acetate extract, the cacalol acetate, and the 2-nitrocacalol acetate was evaluated on the enzymes α-glucosidase and AChE. Finally, the possible mode of ligand–enzyme binding through molecular docking was established. Results The 2-nitrocacalol acetate was obtained with a 20% yield. Its crystallographic structure was obtained, to our knowledge, for the first time, corroborating the S configuration in C5, showing a mostly planar molecule, in which the C6, C7, and C14 atoms and the acetyl group leaving the plane. The ethyl acetate extract was that which significantly inhibited the α-glucosidase (95.8% at 100 μg/mL), while the 2-nitrocacalol acetate exhibited the highest inhibitory activity of the AChE (69.9% at 10 µg/mL). The 2-nitrocacalol acetate presented a favorable interaction energy with the AChE (−8.68 kcal/mol), highlighting the formation of two hydrogen bonds and hydrophobic interactions. Conclusions The 2-nitrocacalol acetate and its crystallographic structure were obtained, to our knowledge, for the first time providing a new modification to this sesquiterpene by introducing a nitro group, which was favored its ability to inhibit AChE. These structural modifications encourage future research in these sesquiterpenes as targets for the development of novel drugs that would be useful in clinical practice.

Synthesis and Characterization of 1-(1-naphthyl)-5-phenyl-2,4-pentadien-1-one from trans-cinnamaldehyde and 1-acetonaphthone

Chalcone analogues (1-(1-naphthyl)-5-phenyl-2,4-pentadiene-1-one) have been synthesized through an aldol condensation reaction between cinnamaldehyde and 1-acetylnaphthalene. The method used in this study is the stirrer method, with the reaction conducted at room temperature for 24 hours using a NaOH catalyst in H2O/ethanol (50%, v/v). The purity of the product was analyzed using thin-layer chromatography on silica gel plates with n-hexane: ethyl acetate (9:1) employed as the solvent. The resulting product obtained was 0.88 g with a yield of 61.97%. Structure Analysis and elucidation of the synthesized compounds were performed by measuring the vibrations of the functional groups using FTIR, LCMSMS analysis, and determining the 1H and 13C atoms by HNMR and CNMR analysis. The FTIR, LCMSMS, 1H, and 13C NMR analysis identified that the synthesized product as chalcone analogues, specifically 1-(1-naphthyl)-5-phenyl-2,4-pentadiene-1-one.

Syntheses, Characterization and Acidochromic Properties of Donor‐Acceptor‐Donor Compounds Based on 2‐Amino‐Pyrimidine

AbstractOrganic materials with a donor‐acceptor‐donor (D−A−D) system of π‐conjugation exhibit strong intermolecular interactions. This study reports the acid‐induced color‐changing properties of two D−A−D type π‐conjugated compounds containing 2‐aminopyrimidine. When the 3,4‐ethylenedioxythiophene (EDOT) moiety is introduced into the D−A−D compound as an electron donor and analyzed through UV‐visible spectroscopy, fluorescence, and thermal characterization, the compound is found to have a narrow bandgap, good thermal stability, and detection ability. The detection limit for methanesulfonic acid is 1.24×10−9 mol/L. Density functional theory (DFT) indicates that both the protonated and unprotonated D−A−D compounds achieve a coplanar geometry. In the acid‐induced color change, the protonated AETP, EDOT′s C1 atom, and the C2 atom of the pyrimidine ring rotate into a head‐to‐head structure, providing sufficient space for proton and pyrimidine N closure. Additionally, The HOMO and LUMO energy levels of ATP and AETP exhibit a notable difference with the former at 2.127 eV and the latter at 2.039 eV. The protonation of these compounds led to a decrease in molecular orbital energy by approximately 50 %, indicating an enhancement in stability relative to their unprotonated counterparts. This observation has significant implications for the design of molecular structures that are responsive to changes in acid concentration, making it valuable for future studies in the field of acid color‐changing compounds.

Photochemical Deracemization of 3-Substituted Oxindoles.

Racemic 3-substituted oxindoles were successfully converted into enantiomerically pure or enriched material (up to 99 % ee) upon irradiation at λ=366 nm in the presence of a chiral benzophenone catalyst (10 mol %). The photochemical deracemization process allows predictable editing of the stereogenic center at carbon atom C3. Light energy compensates for the associated loss of entropy and enables the decoupling of potentially reversible reactions, i.e. a hydrogen atom transfer to (photochemical) and from (thermal) the carbonyl group of the catalyst. The major enantiomer is continuously enriched in several catalytic cycles. The obtained oxindoles were shown to be valuable intermediates for further transformations, which proceeded with complete retention at the stereogenic center.

Photochemical Deracemization of 3‐Substituted Oxindoles

AbstractRacemic 3‐substituted oxindoles were successfully converted into enantiomerically pure or enriched material (up to 99 % ee) upon irradiation at λ=366 nm in the presence of a chiral benzophenone catalyst (10 mol %). The photochemical deracemization process allows predictable editing of the stereogenic center at carbon atom C3. Light energy compensates for the associated loss of entropy and enables the decoupling of potentially reversible reactions, i.e. a hydrogen atom transfer to (photochemical) and from (thermal) the carbonyl group of the catalyst. The major enantiomer is continuously enriched in several catalytic cycles. The obtained oxindoles were shown to be valuable intermediates for further transformations, which proceeded with complete retention at the stereogenic center.

Synthesis of a novel isotopically labelled standard for quantification of γ-nonalactone in New Zealand Pinot noir via SIDA-SPE-GC–MS

γ-Nonalactone is a linear aliphatic lactone ubiquitous in wine, associated with coconut, sweet, and stone fruit aroma descriptors. Little research has been conducted looking at the importance of this compound to New Zealand (NZ) wine aroma. 2H213C2-γ-Nonalactone, a novel isotopologue of γ-nonalactone, was synthesised in this work for use in a stable isotope dilution assay (SIDA) for quantification of γ-nonalactone in NZ Pinot noir wines for the first time. Synthesis was carried out using heptaldehyde as the starting material, and 13C atoms and 2H atoms were introduced via Wittig olefination and deuterogenation steps, respectively. The suitability of this compound as an internal standard was demonstrated by spiking model wine at normal and elevated conditions during sample preparation, with subsequent analysis via mass spectrometry showing stability of 2H213C2-γ-nonalactone. A model wine calibration, with concentrations of γ-nonalactone from 0 to 100 µg L−1, was shown to have excellent linearity (R2 > 0.99), reproducibility (0.72%), and repeatability (0.38%). Twelve NZ Pinot noir wines, representative of a range of NZ Pinot noir–producing regions, prices, and vintages, were analysed by solid-phase extraction–gas chromatography–mass spectrometry (SPE-GC–MS). The concentrations of γ-nonalactone ranged from 8.3 to 22.5 µg L−1, the latter of which was close to the odour detection threshold of this compound. These findings provide a basis for further research into γ-nonalactone and its impact on NZ Pinot noir aroma and provide a robust method for the quantification of this compound in Pinot noir.Graphical abstract

Highly efficient catalytic degradation of dicamba using Fe3O4/montmorillonite composite: Mechanism and toxicity assessment

Dicamba (DIC) posed significant hazards to aquatic environment owing to its toxic and refractory property in agricultural production, which has been paid increasing concern. Herein, a novel magnetic montmorillonite composite (Fe3O4/Mt) was fabricated for catalyzing peroxymonosulfate (PMS) to decompose DIC. The results exhibited that 3.0 mM PMS and 2.0 g/L Fe3O4/Mt could decompose nearly 90% of DIC, and the removal efficiency of DIC stayed above 66% after 10 cycles. The electron spin resonance tests and quenching experiments revealed that SO4•– and •OH were the main active radicals responding for DIC degradation. Moreover, based on the density functional theory (DFT) calculations and LC-MS, C1, C2, C4, and C5 atoms of DIC with high electrophilic activity were prone to be attacked by radicals, and were ultimately decomposed into five degradation intermediates. Finally, the toxicity assessment proved that most of the intermediates exhibited lower toxicity levels than that of DIC. These findings demonstrated that Fe3O4/Mt was a recyclable, stable, and safe catalyst for activation PMS to decompose persistent organic pollutants in contaminated water.

Refinement and complete solution NMR analysis of the structure of a 6-branched 1,3-β-D-glucan (OL-2) isolate from Omphalialapidescens

OL-2 is a water-soluble β-glucan produced by Omphalia lapidescens. This versatile glucan has potential applications in various industries, including food, cosmetics, and pharmaceuticals. In addition, OL-2 is known for its promising applications as a biomaterial and drug, owing to its reported antitumor and antiseptic properties. Although the biological activities of β-glucans vary depending on their primary structure, holistic clarification of OL-2 via solution NMR spectroscopy to ascertain its complete and unambiguous structure has not yet been achieved. In this study, a chain of solution NMR techniques, such as correlation spectroscopy, total correlation spectroscopy (TOCSY), nuclear Overhauser effect and exchange spectroscopy, 13C-edited heteronuclear single quantum coherence (HSQC), HSQC-TOCSY, heteronuclear multiple bond correlation, and heteronuclear 2-bond correlation pulse sequences were used to unambiguously assign all 1H and 13C atoms in OL-2. Based on our investigation, OL-2 consists of a 1,3-β-glucan backbone chain decorated with a single 6-branched β-glucosyl side unit on every fourth residue.

MERCURSOLVOADDUCTS FROM 1-METHYL-2-(2-NITROPHENYL) CYCLOPROPANE AND THEIR TRANSFORMATIONS IN FLUOROSULFONIC ACID

The conjugated addition reaction of mercury (II) acetate in formic acid from the corresponding 1-methyl-2-(2-nitrophenyl)cyclopropanes was used to obtain 1-formyloxy-1-(2-nitrophenyl)-2-methyl-3-chloromercurpropanes and their transformations into fluorosulfonic acid. The interaction of these adducts with FSO3H at a kinetically controlled stage gives predominantly fluorosulfonates of chloromercuric substituted N-oxo-benz[2,1]isoxazolinium ions. As these ions are kept in FSO3H at 20 °C, their protodemercuration occurs, accompanied by the formation of fluorosulfonates of nonmetallated cyclic ions. The complete conversion of fluorosulfonates of metalated ions into non-metallated ions occurs within 84 h from the moment of dissolution of the mercuric solvent adducts in fluorosulfonic acid. In the process of studying the possibilities of synthetic use of 3-chloromercuric-substituted ortho-nitrosoacylbenzenes, it was found that these compounds can easily transform into a previously unknown class of compounds - 3-vinylbenz[c]isoxazoles, which turned out to be very promising synthons. For example, they were used in the synthesis of such hard-to-reach heterocyclic compounds as 1,4-benzodiazepin-2-one dimers, in which benzodiazepinone rings are linked through C5 atoms, and the linker is a cyclobutane ring. Taking into account the fact that the transformation of mercursol water adducts into the corresponding 3-chloromercuric substituted ortho-nitrosoacylbenzenes must proceed through cyclic ions of the benzo[2,1]isoxazolinium type, certain efforts were made to obtain evidence for their formation from 1-methyl-2-mercursol water adducts of (2-nitrophenyl)cyclopropane and 1-methyl-2-(4-bromo-2-nitrophenyl)-cyclopropane in fluorosulfonic acid. Therefore, obtaining new data on the possibilities of the formation of metalated cyclic ions from mercursolvo adducts and on their stability in solutions of strong acids, on the possibilities of isomeric transformations of these ions, as well as their transformation into non-metalated analogs due to protodemercuration, is important both from a practical and theoretical point of view. For citation: Bandaev S.G., Gulov T.Y., Murodov D.S., Kabirov D.N. Mercursolvoadducts from 1-methyl-2-(2-nitrophenyl) cyclopropane and their transformations in fluorosulfonic acid. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 13-22. DOI: 10.6060/ivkkt.20236606.6761.