S. G. Tolshchina

1,2,4,5-Tetrazines and Azolo[1,2,4,5]tetrazines: Synthesis and Reactions with Nucleophiles

The literature data are summarized for synthetic methods and nucleophilic transformations of 1,2,4,5-tetrazines and azolo[1,2,4,5]tetrazines published predominantly from 1995 until 2012.

Synthesis and transformations of cyanomethyl-1,2,4,5-tetrazines

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.

Replacement of dimethylpyrazolyl group in 1,2,4,5-tetrazines by aliphatic alcohols and water

Reactions of 3,6-bis(4-R-3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazines and 3-amino-6-(3,5-dimethyl-1H-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.

Intermolecular interactions in heteromolecular crystals of tetrazine derivatives with azoles

Heteromolecular crystal structures formed by symmetrically and unsymmetrically 3,6-disubstituted tetrazine derivatives with NH donor azoles are investigated. The main crystal motifs and the intermolecular interactions responsible for their formation are identified.

Study of the supramolecular structures of complexes of carborane-containing pyridazines with 2,3,5,6-tetrachloro-1,4-dihydroxybenzene

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.

Reactions of 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines with indole and 1,3,3-trimethyl-2-methyleneindoline

It has been found that 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5- tetrazines react with indole and 1,3,3-trimethyl-2-methyleneindoline to give pyridazines as (4+2)cycloaddition products. 1,3,3-Trimethyl-2-methyleneindoline has been shown to act as C-nucleophile in the substitution of pyrazolyl group as well as in the reactions of tetrazine ring expansion in

Synthesis and antifungal activity of 3-substituted imidazo[1,2-b][1,2,4,5]tetrazines

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.

Synthesis and Tuberculostatic Activity of 2-Alkyl-5-Aryltetrazoles

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.