SummaryThe optimal conditions for regio- and stereoselective epoxide ring opening of N,N-disubstituted 1,2-epoxy-3-aminocyclopentanes by different nucleophilic reagents have been developed. The substituents on the nitrogen atom in the epoxide precursor and the orientation of the oxirane ring are crucial for the reaction outcome. Thus, treatment of (1RS,2SR,3SR)-1,2-epoxy-3-(N,N-dibenzylamino)cyclopentane (3b) with amines gave a mixture of C1 and C2 regioadducts, while the use of (1RS,2SR,3SR)-1,2-epoxy-3-(N-benzyl-N-methylamino)cyclopentane (3a) led ultimately to C1 adducts. Base-catalyzed aminolysis of epoxides 6a,b afforded mainly C1 adducts 13a,b arising from trans-diaxal opening of the epoxide ring. Using a Lewis acid catalyst, epoxides 6a,b were transformed into diaminocyclopentanols 14a,b via an alternative pathway involving the formation of aziridinium intermediate 17.

The regiospecificity of the epoxide ring-opening reactions of (1RS,2SR,3SR)-1,2-epoxy-3-(Nbenzyl-N-methylamino)-cyclopentane 1 and (1RS,2SR,3SR)-1,2-epoxy-3-(N,N-dibenzylamino)-cyclopentane 2 with O-and C-nucleophiles has been explored. It has been shown that electronic and steric factors could affect the regioisomeric ratio of the products due to the possibility for a nucleophile to attack both oxirane carbon atoms. New mimics of 2-deoxystreptamine (2-DOS), the main structural motif of aminoglycoside type antibiotics, have been synthesized.

Background. Anthropogenic impact on agricultural areas leads to pollution of environmental objects, as well as to an increase in the resistance of pathogens to modern means of protection. One of the ways to solve these problems is the development of new drugs based on colloidal solutions of metals synthesized by the “green synthesis” method using aqueous extracts of medicinal plants from central Russia. The biological activity of metal nanoparticles obtained using plant extracts is currently being actively studied in relation to various biological objects. It is advisable to study the effect of iron colloids obtained with the help of an aqueous extract of the common mantle on the growth and development of wheat plants, as well as on phytopathogen fungi, the causative agents of the main diseases of agricultural plants. Purpose. To study the biological activity of iron colloids synthesized on the basis of aqueous extracts of the common cuff. To establish the effect of iron nanoparticles on the growth and development of wheat plants, and to study the fungicidal effect of colloids on pathogenic fungi. Materials and methods. Iron colloids were obtained from plant extracts of various dilutions and iron salt solution. The content of sugars, tannins and dyes, photosynthetic pigments, vegetable protein, flavonoids and ascorbic acid was determined in the composition of the common cuff. The influence of iron colloids on the growth and development of agricultural plants was studied by analyzing the seed germination energy and biometric parameters of wheat germs treated with initial extracts and synthesized colloids. The fungicidal activity of common mantle extracts and iron colloids synthesized on their basis was studied in vitro on the following fungi – phytopathogens: F. moniliforme and F. oxysporum, V. inaequalis, R. solani, B. sorokiniana, P. ostreatus and A. alternata. Results. Growth-stimulating activity is exhibited by aqueous extracts of the common cuff of an average degree of dilution and iron colloids synthesized on their basis. Only extracts of the common cuff have fungistatic properties in relation to the fungus B. sorokiniana. Conclusion. Biological activity is shown by extracts of medium dilution and colloids synthesized on their basis. In further research on this topic, it is advisable to study the effect of various variations in salt and extract concentrations on the manifestation of fungicidal and growth-stimulating activity.

Background. The problem of finding new effective plant protection products remains an urgent task of modern agrochemistry. It is known that tetrahydropyridine derivatives exhibit a broad spectrum of biological activity, including fungicidal activity. However, compounds with potential biological activity can also be highly toxic to humans, cultivated crops, and the environment as a whole, so it is necessary to study their environmental safety. The content of photosynthetic pigments and ascorbic acid are one of the most important biochemical indicators of plant response to environmental stress factors, therefore, determining their amount helps to assessthe physiological state of plants and analyze the toxicity of the synthesized compounds. Purpose. To study the effect of new 6-R-3,5-dinitro-1,2,3,4-tetrahydropyridines on the content of photosynthetic pigments and ascorbic acid in plant tissues in order to assess the safety of their use as potential plant protection products. Materials and methods. The test compounds were obtained by the previously developed method for the selective reduction of 2-R-3,5-dinitropyridines. Winter wheat seeds of the Moskovskaya 39 variety were germinated in Petri dishes using solutions of the synthesized substances. Seeds germinated in water were used as controls. On the ninth day, the content of various groups of photosynthetic pigments (chlorophylls a, b, carotenoids), as well as ascorbic acid in plant tissues was determined. All experiments were carried out in triplicate. In addition, the analytes were tested for toxicity using the GUSAR Environmental Toxicity software. Results. The effect of new derivatives of tetrahydropyridine on the accumulation of photosynthetic pigments and ascorbic acid in plant tissues of winter wheat was studied. It was shown that the studied compounds do not have a significant toxic effect on plants. Conclusion. As a result of studying the effect of new 6-R-3,5-dinitro-1,2,3,4-tetrahydropyridines on the content of photosynthetic pigments and ascorbic acid, as well as in silico computer prediction in GUSAR Environmental Toxicity, it was found that, in general, the studied compounds are relatively safe and, therefore, promising for further testing as biologically active plant protection products.

A number of new derivatives of N-(3-R-1,5-dinitro-8-oxo-3-azabicyclo[3.3.1]non-6-en-7-yl)acetamides have been synthesized by Mannich condensation of hydride σ-adduct of the N-(2-hydroxy-3,5-dinitrophenyl)acetamide with formaldehyde and primary amines. The synthesis was carried out with two stages. In the first stage, under the action of sodium tetrahydride borate on a solution of N-(2-hydroxy-3,5-dinitrophenyl)acetamide, the C = C bonds of the aromatic ring were reduced to form a 3-charge hydride adduct. The resulting diaduct was isolated from the solution and, while cooling with ice, was introduced into Mannich-condensation with formaldehyde and a solution of the primary amine or amino acid. When the reaction mixture was acidified with dilute orthophosphoric acid to pH 4–5, precipitates of the target products precipitated. After recrystallization from ethanol, the yield of the target products, depending on the substituent at the nitrogen atom, ranged from 55 to 90%. This method is distinguished by relative simplicity, availability of reagents and allows under mild conditions to transfer from the aromatic system activated by nitro groups to 3-azabicyclo[3.3.1]nonane derivatives, containing promising from the point of view of further functionalization nitro, carbonyl and amino groups. The structure of the compounds obtained was proved by IR, 1H-, 13C-, two-dimensional correlation NMR spectroscopy, as well as elemental analysis data. In the IR spectra of the obtained substances, the characteristic absorption bands of amide I (1629-1633 cm-1) and amide II (1560-1570 cm-1), as well as antisymmetric (1549-1556 cm-1) and symmetric (1370-1377 cm-1) oscillations of nitro groups were observed. In the NMR spectra in the weakest field, the broadened signal of the proton NH is observed (δ 9.51-9.57 ppm), followed by the singlet signal of the proton at the double bond (δ 8.15-8.16 ppm). The protons of the methylene groups of the bicyclic system are diastereotopic. Therefore, their signals are mutually split into broadened doublets located in the region of 2.66–3.46 ppm.