The reaction of 3-azolyl-6-R-1,2,4,5-tetrazines with guanidine afforded a series of new 3-guanidino-6-R-1,2,4,5-tetrazines. When treated with hydrogen peroxide, these compounds can undergo oxidative transformation of the tetrazine ring to form 2,5-disubstituted 1,3,4-oxadiazoles. The reaction of the new tetrazines with concentrated nitric acid leads to the nitration of functional groups in the tetrazine ring.

New 3,6-disubstituted 1,2,4,5-tetrazine derivatives with pyridyl-substituted amidine moieties, as well as [1,2,4]triazolo[1,5-b][1,2,4,5-tetrazines and bis[1,2,4]triazolo-[1,5-b:1,5-f][1,2,4,5]tetrazines on their basis were synthesized. The obtained compounds were screened for activity against Neisseria gonorrhoeae and Mycobacterium tuberculosis. Compounds with pronounced antibacterial activity were detected. Docking was performed to determine a possible antibacterial effect of the compounds.

A number of new 3-alkylthio-6-(3,5-dimethylpyrazol-1-yl)[1,2,4]triazolo[4,3-b][1,2,4,5]-tetrazines were synthesized and modified in nucleophilic substitution reactions with aliphatic amines. The study of the tuberculostatic activity of the compounds obtained revealed a number of active derivatives with a minimum inhibitory concentration of 0.37–3.1 µg mL−1.

According to the in silico consensus activity prediction, a series of 3,6-disubstituted 1,2,4,5-tetrazines were synthesized as promising inhibitors of the Maillard reaction. In addition to the studies of antiglycation activity, a comparative in vitro evaluation of the effect of the synthesized compounds on the ADP-induced rabbit platelet aggregation model was carried out. Compounds with antiglycation and antiplatelet activities significantly higher than that of the reference drugs, aminoguanidine and acetylsalicylic acid, were revealed.

Nucleophilic substitution and 1,3-dipolar cycloaddition reactions were used to synthesize 3,6-disubstituted derivatives of simm-tetrazine containing azolyl, aminoalkyl, and oxyalkyl fragments. The antibacterial activity of the resulting compounds was studied using the obligate pathogen Neisseria gonorrhoeae and opportunistic pathogenic microorganisms, while antifungal activity was assessed using anthropo- and zooanthropophilic dermatophytes.

2-Substituted 5-aryltetrazoles containing alkyl and aminoalkyl fragments were synthesized using alkylation and Mannich reactions. The tuberculostatic activity of the synthesized compounds against strain M. tuberculosis H37Rv was studied. Pronounced tuberculostatic activity (MIC ≤ 1.5 ìg/mL) was found for tetrazoles containing N(2) dimethyl- and diethylaminoethyl fragments.

The reaction of azoloannulated [1,2,4,5]tetrazines with guanidine was studied. New 3-guanidinoimidazo[1,2-b]- and 6-guanidino[1,2,4]triazolo[4,3-b] [1,2,4,5]tetrazines were synthesized using the nucleophilic substitution methodology. Compounds with high antibacterial and antiglycation activity were revealed.

New tetrazolyl derivatives of pyrimidine were synthesized containing various linker groups. The structure of these compounds was established by NMR spectroscopy and X-ray diffraction analysis.

The N(1)—N(1), N(2)—N(2), and N(1)—N(2) regioisomers of 1,2-bis[(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane were first synthesized by alkylation of 1,2-bis(1H-tetrazol-5-yl)ethane with propargyl bromide. The peculiarities of the crystal structure of 1,2-bis[1-(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane were evaluated by X-ray diffraction analysis. This compound is readily underwent Cu-catalyzed [3+2] cycloaddition with p-tolyl azide, p-nitrophenyl azide, and benzyl azide to give heterocyclic assembles bearing 1,2,3-triazole and tetrazole cycles. Catalyst-free [3+2] cycloadditions of 1,2-bis[1-(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane and the mixtures of the N(1)—N(1), N(2)—N(2), N(1)—N(2) regioisomers with poly(glycidyl azide) oligomers resulted in 1,2,3-triazole cycles and crosslinking of the polymer chains.

A number of new 3-substituted imidazo[1,2-b][1,2,4,5]tetrazines containing azolyl, aminopyridyl, and alkoxyl substituents was synthesized. These compounds were studied for the biological activity against mycelial anthropophilic and zoophilous dermatophyte fungi (Trichophyton, Microsporum and Epidermophyton), causing diseases of skin and its appendages (hair, nails), and yeast-like fungi Candida.

The structures and characteristic features of the molecular packing patterns of complexes of pyridazines containing heterocyclic substituents and the carborane moiety with 2,3,5,6-tetrachlorohydroquinone (TCHQ) were investigated. It was shown that TCHQ can form supramolecular assemblies with carborane-containing substituted pyridazines. The stoichiometry and three-dimensional structures of these assemblies depend on the substituents in the pyridazine ring and are formed via O-H…N hydrogen bonding between TCHQ and heterocyclic molecules.

A series of novel 3,6-disubstituted 1,2,4,5-tetrazines and pyridazines bearing aminopyridyl, hydrazono, or aminoalkyl substituents were synthesized. Ten of these compounds showed marked tuberculostatic activity (MIC ≤ 12.5 mkg mL −1 ).

Derivatives of s-tetrazine containing malonodinitrile, ethyl cyanoacetate, and 1,3-indanedione fragments were synthesized by the nucleophilic substitution of heterocyclic groups in 3,6-diazolyl-1,2,4,5-tetrazines. Coordination compounds of the cyanomethyltetrazine anion with Cu+, Mn2+, and the tetrathiafulvalene radical cation were obtained, and their structures were determined. A transformation of cyanomethyltetrazines to pyrrolo[1,2-b][1, 2, 4, 5]tetrazines catalyzed by metal cations was discovered.

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.

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.

The reactions of 3,6-disubstituted and azoloannulated 1,2,4,5-tetrazines containing heterocyclic leaving groups with S-nucleophiles were studied. The methods of introduction of functionalized thiols, including thiol derivatives of 1,7- and 1,2-dicarba- closo -dodecaboranes, into the tetrazine ring were developed. It was established for the first time that, instead of replacement of a leaving group in the tetrazine ring, the attack of S-nucleophile at the unsubstituted carbon atom occurs in the case of imidazo[1,2- b ][1,2,4,5]tetrazines to form previously unknown products of nucleophilic substitution of the hydrogen atom.

Previously unknown products of the cyclocondensation of 1,1,1-trifluoro-2,4-pentanedione with triaminoguanidine and hydrazine derivatives of 1,2,4,5-tetrazine have been obtained. 5-Hydroxy-5-trifluoromethylpyrazoline substituents formed on the tetrazine ring were dehydrated under the action of trifluoroacetic anhydride. A comparison has been carried out of the reactivity of 5-trifluoromethylpyrazolyl-substituted 1,2,4,5-tetrazines and their unfluorinated analogs in nucleophilic substitution and [4 + 2] cycloaddition reactions.

The [4+2] cycloaddition reactions of 3,6-disubstituted 1,2,4,5-tetrazines with 9-allyl-1,7-,9-allyl-1,2-dicarba- closo -dodecaboranes and 1-allyl-2-isopropyl-1,2-dicarba- closo -dodecab-orane have been studied. The pyridazines containing carborane cage have been synthesized for the first time.

Reactions of 3,6-bis(4-R-3,5-dimethyl-1 H -pyrazol-1-yl)-1,2,4,5-tetrazines and 3-amino-6-(3,5-dimethyl-1 H -pyrazol-1-yl)-1,2,4,5-tetrazines with aliphatic alcohols and water in the presence of a base involved replacement of the dimethylpyrazolyl group and resulted in the formation of mono- and dialkoxy-1,2,4,5-tetrazines and 6-substituted 3-hydroxy-1,2,4,5-tetrazines. Dissociation constants of the latter were determined by potentiometric titration.