A new series of pyrazolylpyridazine derivatives was obtained on the basis of 3-pyrazol-1-yl-6-hydrazinylpyridazine. Biological screening has identified a number of compounds that have a stimulating effect on plant growth.

For the first time, eco-friendly ultrasound-assisted synthesis of a series of S-substituted 6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine-3(2H)-thione derivatives based on 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine was performed. The reaction times, temperatures, and yields of reaction products were compared with MW-assisted and conventional methods. An in silico study to predict the biological activity of the studied compounds was carried out. Physicochemical and pharmacokinetic properties, ADMET properties and bioavailability index were calculated.

Pyrazolylpyridazine is an interesting non-fused biheterocyclic system, which derivatives have a wide spectrum of biological activity. In this study, a targeted synthesis of a number of new potentially biologically active derivatives based on the corresponding 2-{[6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazin-3-yl]thio}acetohydrazide was carried out. The synthesized compounds showed a pronounced stimulating effect on plant growth.

Several chalcones and their pyrazole derivatives have been synthesized using traditional methods under microwave (MW) and ultrasonic (US) irradiation. The latter were synthesized using US-assisted and MW-assisted one-pot techniques. The use of this technology led to a reduction in reaction time and energy consumption, as well as an increase in the yield of the final products, which means more efficient synthesis. An in silico study was conducted and the plant growth-stimulating effects of the synthesized compounds were revealed. To study the growth-regulating activity of the synthesized compounds, a study of aqueous suspensions at a concentration of 50 and 25 mg·L ⁻¹ was carried out on the viability, germination, and growth of seeds.

Based on 3-chloro-6-hydrazinylpyridazine, a series of new derivatives containing the arylidenehydrazinyl-6-chloropyridazine fragment, were synthesized using conventional methods and under microwave irradiation. Experimental data indicate that when using a technique that meets the requirements of green chemistry, in the vast majority of cases higher yields of final products are achieved with a simultaneous sharp reduction in reaction times, which leads to significant savings in energy resources. Biological tests were carried out on seeds and seedlings of common bean (Phaseolus vulgaris L.). The screening showed that the synthesized compounds exhibit pronounced stimulating activity in plant growth and may be promising in searching for new growth stimulators. In silico study of synthesized compounds were carried out.

Background and Aim: With the emergence of severe acute respiratory syndrome-related coronavirus (SARS-CoV-2), antiviral drug development has gained increased significance due to the high incidence and potentially severe complications of the resulting coronavirus infection. Heterocycle compounds, acting as antimetabolites of DNA and RNA monomers, rank among the most effective antiviral drugs. These compounds’ antiviral effects on various SARS-CoV-2 isolates, as found in existing data collections, form the basis for further research. The aim of this study was to examine the possible antiviral effect of some originally synthesized heterocyclic compounds. Materials and Methods: The main methods were cell culturing, cytotoxicity assay, qRT-PCR assay, tissue and blood cells analysis, and micro-computed tomography (micro-CT) imaging. Results: In both in vitro and in vivo conditions, the elimination of SARS-Cov-2 occurred significantly earlier after administration of the compounds compared to the control group. In hamsters, the primary symptoms of coronavirus disease disappeared following administration of heterocycle compounds. Conclusion: Using delta and omicron strains of the SARS-CoV-2 virus, newly created heterocycle compound analogs dramatically reduced SARS-CoV-2 multiplication, resulting in a drop in viral RNA load in the supernatant under in vitro conditions. Improvements in pathological manifestations in the blood, bone marrow, and internal organs of hamsters demonstrated that heterocycle compounds inhibited SARS-CoV-2 replication both in vitro and in vivo. Keywords: broad-spectrum antiviral agents, heterocycle compounds, in vitro, in vivo, severe acute respiratory syndrome-related coronavirus, Syrian hamsters.