Tatiana A. Kalinina

Synthesis of condensed [1,2,3]triazolo-[5,1-b][1,3,4]thiadiazepine systems

In contemporary organic chemistry, rearrangements and transformations of one type of heterocycle to another are promising and convenient methods for the preparation of heterocyclic structures difficult to obtain by other means. However, these reactions are rarely used as a planned method for preparing heterocyclic systems. 1,2,3-Thiadiazoles are convenient starting materials for carrying out various rearrangements. Several rearrangements of 1,2,3-thiadiazoles involving a substituent in the ring position 5 are known [1-3], but only a few of these lead to the preparation of condensed 1,2,3-triazoles. Thus, for example, methods are known for the synthesis of [1,2,3]triazolo[5,1-b][1,3,4]thiadiazines using the Dimroth rearrangement [4, 5].

Synthesis of (1,2,3-thiadiazolyl)imidazolidine-2,4-diones by microwave irradiation and characterization of their biological activity

The effects of microwave irradiation on the synthesis of (1,2,3-thiadiazol-4-yl)- and (1,2,3-thiadiazol-5-yl)imidazolidine-2,4-diones by cyclocondensation of the respective (1,2,3-thiadiazolyl)ureidoacetic acids were studied. The reactions were studied under the conditions of traditional heating at 140°C temperature and microwave irradiation at 170°C. It was shown that microwave heating of (1,2,3-thiadiazol-5-yl)ureido derivatives of carboxylic acids led to the formation of imidazolidine ring, unlike in the case of (1,2,3-thiadiazol-4-yl)ureido derivatives, for which traditional heating was more effective. The derivatives of (1,2,3-thiadiazolyl)imidazolidine-2,4-diones and (1,2,3-thiadiazolyl)ureidoacetic acids were studied with regard to their effects on pine seed germination and seedling growth.

Synthesis of spiro derivatives of 1,2,3-triazolo[5,1- b ][1,3,4]thiadiazines and biological activity thereof

3-Cyclopentylidene(cyclohexylidene)amino-3H-1,2,3-triazole-4-thiolates, formed via Dimroth rearrangement of 1,2,3-thiadiazolylhydrazones of cyclopentanone and cyclohexanone in the presence of triethylamine, reacted in situ with α-bromoacetophenones with the formation of spirocyclic 6,7-dihydro-5H-[1,2,3]triazolo[5,1-b][1,3,4]thiadiazines. The effect of the obtained compounds on the viability and proliferative activity of four lines of cell cultures was studied. The selective proliferative activity was determined.

Synthesis of 5-(pyrazol-1-yl)-1,2,3-thiadiazoles

A method is proposed for the synthesis of ethyl 5-(3-aryl-4-formyl-1H-pyrazol-1-yl)-1,2,3-thiadiazole-4-carboxylates by a reaction of acetophenone (4-ethoxycarbonyl-1,2,3-thiadiazol-5-yl)hydrazones with a Vilsmeier–Haack complex. The obtained heterocyclic assemblies provide interesting substrates for further modification and study of biological activity.

Discovery of Methyl (5Z)-[2-(2,4,5-Trioxopyrrolidin-3-ylidene)-4-oxo-1,3-thiazolidin-5-ylidene]acetates as Antifungal Agents against Potato Diseases

Synthesis, isomerism, and fungicidal activity against potato diseases of new (5 Z)-[2-(2,4,5-trioxopyrrolidin-3-ylidene)-4-oxo-1,3-thiazolidin-5-ylidene]acetate derivatives with 1,3-thiazolidine-4-one and pyrrolidine-2,3,5-trione moieties linked by an exocyclic C═C bond were described. Their structures were clearly confirmed by spectroscopic and spectrometric data (Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance, and mass spectrometry), elemental analysis, and X-ray diffraction crystallography. A bioassay for antifungal activity in vitro against Phytophthora infestans, Fusariun solani, Alternaria solani, Rhizoctonia solani, and Colletotrichum coccodes demonstrated that 2,4,5-trioxopyrrolidin-1,3-thiazolidine derivatives exhibited a relatively broad spectrum of antifungal activity. One of the compounds showed considerable activity against all of the strains; in the case of F. solani, P. infestans, and A. solani, it possesses comparable or better fungicidal efficacy than the positive control Consento. Consequently, this compound is a promising fungicidal candidate for plant protection.

Synthesis and evaluation of the influence of 5-sulfanyl-1,2,3-triazol-1-ylaminocarboxylic acid derivatives on kinetics of ascorbic acid oxidation

Abstract1,2,3-Thiadiazolylureas containing amino acid residues were synthesized. These compounds were converted to 5-sulfanyl-1,2,3-triazol-1-ylaminocarboxylic acid sodium salts under alkaline conditions. These salts were found to inhibit the oxidation of ascorbic acid with air oxygen. In the presence of the equimolar amount of 5-sulfanyl-1,2,3-triazoles, the rate of diminution of ascorbic acid decreased by 1.5—3 times, whereas in the case of their two-fold excess by a factor of 5.