Solvent-dependent transformations of polysubstituted 2-acetyl-2,5-dihydrothiophenes to the corresponding 2-hydroxy- or deacetylated derivatives are described. The treatment of a methanolic solution of the dihydrothiophene substrates with sodium methoxide afforded the deacylated products. Conversely, the treatment with sodium ethoxide in an oxygen saturated ethanolic solution produced 2-hydroxy substituted 2,5-dihydrothiophenes.

An azide-free approach toward N -sulfonyl amidines, including phosphorus-containing derivatives based on the reactions of thioamides and thiophosphonyl diamides with iminoiodinanes, was developed.

Transition metal-catalyzed and noncatalytic reactions of acrylic thioamides with N-sulfonyliminoiodinanes enabling the selective synthesis under mild conditions of a series of fully decorated S- and N,S-containing heterocycles are described. Fine-tuning of the thioamide structure allows selective preparation in good yields of ortho-fused thiophenes, 1,2-thiazines, and spiro-fused isothiazolines. A one-pot thermally induced rearrangement of sulfonylisothiazolines was discovered as a complementary route to thiophenes.

A one-step method has been developed for the preparation of 2,3-dihydro-2-sulfonyl-3,4,5-substituted 1,2-thiazoles by the reaction of acryl thioamides and iminoiodinanes. A library of 31 examples of tetrasubstituted 1,2-thiazoles was thus synthesized in high yields. The effectiveness of the synthesis method for these poorly studied 1,2-thiazoles was confirmed by scaling the reaction using gram amounts of the starting thioamide.

Metal-free reactions of thioacetamide derivatives with N-sulfonyliminoiodinane, affording isothiazoles under mild conditions, are described. 2-Substituted thioacetamides modified with an enamine moiety undergo reactions with iminoiodinane to form 4,5-disubstituted isothiazoles in 72-93% yields. Reactions of (het)arylidene-substituted 2-thioacetamides and iminoiodinane with subsequent one-pot oxidation of the formed sulfonylisothiazolines afford 3,4,5-trisubstituted isothiazoles in 44-96% yields. A scale-up synthesis of the developed methods was performed. The photophysical properties of the new isothiazoles were investigated, and UV- or blue-light-shifted fluorescence has been detected (QY up to 11%).

Pyrroles incorporating conjugated exocyclic C=C and C=O bonds were obtained in the reaction of 3,3-diaminoacrylonitriles with aroyl-(heteroaroyl)pyruvic acid esters. A simple and efficient method for the synthesis of pyrroles was developed based on this reaction, which makes it possible to vary the substituents in positions 1 and 5 of the pyrrole ring and in the 2-oxoethylidene fragment.

An azide-free approach toward N -sulfonyl amidines, including phosphorus-containing derivatives based on the reactions of thioamides and thiophosphonyl diamides with iminoiodinanes, was developed.

An overview of the main scientific achievements of Russian universities in the field of organic chemistry over the period 2018–2023 is presented.

A novel and efficient base-catalyzed, transition-metal-free method for the synthesis of diheterocyclic compounds connected by an amidine linker, including apart from the common 1,2,3-triazole ring, either an additional pyrimidinedione, 4-nitroimidazole, isoxazole, 1,3,4-triazole, 2-oxochromone or thiazole ring, has been developed. The process was facilitated by a strong base and includes the cycloaddition reaction of 3,3-diaminoacrylonitriles (2-cyanoacetamidines) to heterocyclic azides followed by a Cornforth-type rearrangement to the final products. The reaction is tolerant to various N-monosubstituted 3,3-diaminoacrylonitriles and to different heterocyclic azides. The developed method has a broad scope and can be applied to obtain a variety of N-heteroaryl-1,2,3-triazole-4-carbimidamides with alkyl, allyl, propargyl, benzyl, cycloalkyl, and indolyl substituents at the N1 position .

A Rh(ii)/Cu(i)-catalyzed [4 + 1]-annulation of readily available thioamides with 1-sulfonyl-1,2,3-triazoles and diazoamides was developed, delivering a general approach toward highly substituted dihydrothiophenes. A series of dihydrothiophenes having a wide diversity of functional groups, including spirocyclic, dispirocyclic and bicyclic derivatives were synthesized in high yields and good diastereoselectivity. The diastereoselectivity for the reaction of 2-(morpholino-4-carbonothioyl)-3-phenylacrylonitrile with diazoacetamides can be switched by replacing Rh(ii) with a Cu(i) catalyst. Cycloalkylidene substituted thioamides formed various regioisomers under Rh(ii) or Cu(i) catalysis. Furthermore, reactions of 3-diazomethylindolin-2-one with thioamides can be performed enantioselectively with ee up to 97%. Catalyst-controlled regioselective and diastereoselective reactions of thioamides with diazoamides and 1-sulfonyl-1,2,3-triazoles was developed. Enantioselective and gram-scale syntheses were performed.

An approach to developing a docking protocol using free software such as KNIME, DataWarrior, AutoDock Vina, AutoDockTools, OpenBabel and the SWISS-MODEL service was described. In particular, the process of generating possible isomeric structures using KNIME chemoinformatics libraries is described. A library of benzo[d]azoles containing 145 compounds with homologous models of Alternaria solani β-tubulin obtained in two ways: using the commercial Prime program and the free SWISS-MODEL service, the comparison of results was shown. Despite the less preorganization of the binding cavity of the homologous model obtained using SWISS-MODEL, the correlation of the results between the two methods were observed. The correlation coefficients were as follows: Pearson was 0.65, Spearman was 0.62. According to the docking results, 99% of the studied 2-aminobenzo[d]azoles derivatives showed a docking score of no more than –7, which indicates that these compounds are promising for studying the fungicidal activity, in particular against A. solani. Without taking into account pharmacokinetic characteristics, benzo[d]imidazole derivatives containing a sulfanilamidine substituent at the 2-amino group and thioacetyl derivatives of 2-aminobenzo[d]imidazole are of particular interest in the search for new antitubulin fungicides.

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 present, more than half of the hundreds of millions of known chemical compounds are heterocycles. This collective review is devoted to the achievements of Russian chemists in this field over the last 15–20 years. The review presents the achievements of leading heterocyclists representing both RAS institutes and university science. It is worth noting the wide scope of the review, both in terms of the geography of author teams, covering the whole of our large country, and in terms of the diversity of research areas. Practically all major types of heterocycles are represented in the review. The special attention is focused on the practical applications of heterocycles in the design of new drugs and biologically active compounds, high-energy molecules, materials for organic electronics and photovoltaics, new ligands for coordination chemistry, and many other rapidly developing areas. These practical advances would not be possible without the development of new fundamental transformations in heterocyclic chemistry. Bibliography — 2237 references.

The addition of active groups of known fungicides, or systemic acquired resistance inducers, into novel compound molecules to search for potential antifungal compounds is a popular and effective strategy. In this work, a new series of N-acyl-N-arylalanines was developed and synthesized, in which 1,2,3-thiadiazol-5-ylcarbonyl or 3,4-dichloroisothiazol-5-ylcarbonyl (fragments from synthetic plant resistance activators tiadinil and isotianil, respectively) and a fragment of N-arylalanine, the toxophoric group of acylalanine fungicides. Several new synthesized compounds have shown moderate antifungal activity against fungi in vitro, such as B. cinerea, R. solani and S. sclerotiorum. In vivo tests against A. brassicicola showed that compound 1d was 92% effective at a concentration of 200 µg/mL, similar to level of tiadinil, a known inducer of systemic resistance. Thus, 1d could be considered a new candidate fungicide for further detailed study. The present results will advance research and influence the search for more promising fungicides for disease control in agriculture.

A large variety of 1,2,3-thiadiazoles and 1,2,3-triazoles are used extensively in modern pure and applied organic chemistry as important structural blocks of numerous valuable products. Creation of new methods of synthesis of these isomeric compounds requires the development of reliable analytical tools to reveal the structural characteristics of these novel compounds, which are able to distinguish between isomers. Mass spectrometry (MS) is a clear choice for this task due to its selectivity, sensitivity, informational capacity, and reliability. Here, the application of electrospray ionization (ESI) with ion detection in positive and negative modes was demonstrated to be useful in structural studies. Additionally, interconversion of isomeric 4,5-functionalized 1,2,3-triazoles and 1,2,3-thiadiazoles was demonstrated. Application of accurate mass measurements and tandem mass spectrometry in MS2 and MS3 modes indicated the occurrence of gas-phase rearrangement of 1,2,3-triazoles into 1,2,3-thiadiazoles under (+)ESI-MS/MS conditions, independent of the nature of substituents, in line with the reaction in the condensed phase. Infrared multiple photon dissociation (IRMPD) spectroscopy enabled the establishment of structures of some of the most crucial common fragment ions, including [M+H-N2]+ and [M+H-N2-RSO2]+ species. The (−)ESI-MS/MS experiments were significantly more informative for the sulfonyl alkyl derivatives compared to the sulfonyl aryl ones. However, there was insufficient evidence to confirm the solution-phase transformation of 1,2,3-thiadiazoles into the corresponding 1,2,3-triazoles.

(4-Methoxyphenyl)di(pyrrolidin-1-yl)phosphine sulfides were synthesized by the reaction of Lausson’s reagent with cyclic amines. It was shown for the first time that phosphine sulfides react with arenesulfonyl azides in 1,4-dioxane under reflux with the elimination of nitrogen and elemental sulfur to form previously unknown dicycloaminophosphoranylidene sulfonamides.

The reaction of 3,3-diaminoacrylonitriles with DMAD and 1,2-dibenzoylacetylene was studied. It is shown that the direction of the reaction depends on the structure both of acetylene and of diaminoacrylonitrile. In the reaction of DMAD with acrylonitriles bearing a monosubstituted amidine group, 1-substituted 5-amino-2-oxo-pyrrole-3(2H)ylidenes are formed. On the other hand, a similar reaction of acrylonitriles containing the N,N-dialkylamidine group affords 1-NH-5-aminopyrroles. In both cases, pyrroles containing two exocyclic double bonds are formed in high yields. A radically different type of pyrroles containing one exocyclic C=C bond and sp(3) hybrid carbon in the cycle is formed in reactions of 3,3-diaminoacrylonitriles with 1,2-diaroylacetylenes. As in reactions with DMAD, the interaction of 3,3-diaminoacrylonitriles with 1,2-dibenzoylacetylene can lead, depending on the structure of the amidine fragment, both to NH- and 1-substituted pyrroles. The formation of the obtained pyrrole derivatives is explained by the proposed mechanisms of the studied reactions.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

It was shown that the reaction of 2-cyanothioacetamides with hydrazine involves both cyano- and thioamide groups, and 3,5-diaminopyrazoles are formed. In the reaction of 2-cyano-3-(dimethylamino)-N,N-dimethylprop-2-enethioamides with hydrazine and its derivatives, the interaction proceeds with the participation of cyano- and enamine groups, not affecting the thiocarbamoyl group, and leads to the formation of 4-thiocarbamoylpyrazoles. A synthesis method has been developed and a series of 1-substituted-4-thiocarbamoyl pyrazoles has been thus synthesized. The structure of the reaction products was studied using NMR spectroscopy and mass spectrometry and confirmed by X-ray diffraction analysis.

An efficient base-catalyzed, metal-free method for the synthesis of 5-amino-1,2,3-triazole-4-N-sulfonyl- and arylimidamides, directed by the structure of the amidine group, has been developed. It is based on a previously unknown tandem process involving cycloaddition reaction to 3,3-diaminoacrylonitriles (2-cyanoacetamidines) with aryl(alkyl)sulfonyl or aryl azides and Cornforth-type rearrangement. During the reaction optimization, different factors were found to facilitate the title reaction, which include the use of a strong base and N-mono- or N,N'-disubstituted 3,3-diaminoacrylonitriles. The reaction is tolerant to variously N-monosubstituted and N,N'-disubstituted 3,3-diaminoacrylonitriles and to various aryl- and aryl/alkyl sulfonyl azides. The developed method has a broad scope and can be applied to obtain a variety of 5-amino-1,2,3-triazole-4-carbimidamides bearing at the N1 position alkyl, allyl, propargyl, benzyl, cycloalkyl, and heteroaryl substituents and sulfonyl and aryl substituents at the amidine group. Post-cyclization reactions of prepared 5-amino-1,2,3-triazoles with DMF-DMA DMA-DMF leads to 1,2,3-triazolo[4,5-d]pyrimidines, 8-aza purine analogues demonstrating the applicability of the prepared compounds in organic synthesis.