3-(5-Phenyl-2H-tetrazol-2-yl)pyridine was synthesized by treating 5-phenyl-1H-tetrazole with pyridin-3-ylboronic acid under Chan–Evans–Lam coupling conditions. The structure and identity were confirmed by 1H, 13C-NMR spectroscopy, IR spectroscopy, UV–Vis spectroscopy, high-resolution mass spectrometry, and TLC. The molecular structure was studied experimentally by sequential X-ray diffraction analysis and theoretically by DFT B3LYP quantum chemistry calculation.

Highly purified 5-vinyl-1H-tetrazole was synthesized, which is in great demand in modern medicine and industry as a monomer for obtaining nitrogen-rich macromolecular compounds and a reagent for the complete synthesis of biological compounds. The molecular structure was studied experimentally with sequential X-ray diffraction analysis and theoretically with ab initio quantum chemical calculations. The data from differential scanning calorimetry, nuclear magnetic resonance (1H, 13C, 1H-15N, HMBC), high-resolution mass spectrometry and vibrational spectroscopy were analyzed. The results are useful for evaluating the possibility of extending the polymerization of 5-vinyl-1H-tetrazole to synthesize polymers with predictable molecular weight and thermodynamic parameters.

The kinetics and mechanism of the Curtius rearrangement of m-nitrobenzoyl azide in aqueous solutions of sulfuric acid of various concentrations has been studied. An increase of the acidity of the reaction solution an increase in the acidity of the reaction solution leads to an acceleration of the rearrangement. The rate-limiting step of the reaction is the rearrangement of the protonated form of m-nitrobenzoyl azide to the corresponding isocyanate

The kinetics of the nitration reaction of m-nitrobenzoic acid with nitric acid in a sulfuric acid medium of various concentrations was studied by UV spectroscopy. The observed differences in the rate of nitration of m-nitrobenzoic acid from the nitration of alkylbenzenes are associated with the electron-withdrawing nature of the carboxyl group, as well as with its protonation. During the reaction, not only 3,5-dinitrobenzoic acid is formed, but also products with significantly higher molar absorption coefficients

3-{[(1-Methyl-1 H -tetrazol-5-yl)imino]methyl}quinoline-2-thiol and 3-{[(2-methyl-2 H -tetrazol-5-yl)imino]methyl}quinoline-2-thiol were synthesized. The sequence of the thiol-Michael reaction and the (aza)-Morita–Baylis–Hillman reaction yielded 4-[(1-methyl-1 H -tetrazol-5-yl)amino]-2-phenyl-4 H -thiopyrano[2,3- b ]quinoline-3-carbaldehyde, 4-[(2-methyl-2 H -tetrazol-5-yl)amino]-2-phenyl-4 H -thiopyrano[2,3- b ]-quinoline-3-carbaldehyde, and 4-hydroxy-2-phenyl-4 H -thiopyrano[2,3- b ]quinoline-3-carbaldehyde. Cytotoxicity and antiviral activity against the A/Puerto Rico/8/34 (H1N1) influenza virus strain in MDCK cell culture were determined for the obtained compounds. The study showed that the replacement of the hydroxyl group in 4-hydroxy-2-phenyl-4 H -thiopyrano[2,3- b ]quinoline-3-carbaldehyde with a 1-methyl- or 5-amino-2-methyltetrazolyl fragment decreased antiviral activity. At the same time, 3-{[(1-methyl-1 H -tetrazol-5-yl)imino]-methyl}quinoline-2-thiol has a higher activity than 3-{[(2-methyl-2 H -tetrazol-5-yl)imino]methyl}quinoline-2-thiol. This fact indicates a possible relationship between the arrangement of substituents in the tetrazole ring and the antiviral activity of the tested heterocyclic system. Supplementary Information The online version contains supplementary material available at 10.1007/s10593-022-03083-w.