Vol 92, No 1 (2023)
Articles
Antiviral properties of diterpenes and their derivatives
Abstract
The review focuses on low-molecular-weight natural metabolites of the diterpene series and their semi-synthetic analogues, which exhibit antiviral activity. Data on the antiviral activity of both plant extracts and their components are provided. The structures of biologically active natural diterpenoids and their derivatives with a pronounced antiviral effect are presented. Mechanisms of therapeutic action of diterpenoids and their derivatives with a pronounced antiviral effect are considered for different viruses. The review summarizes the data over the last 12 years (2011–2022). The bibliography includes 183 references.
Uspehi himii. 2023;92(1):RCR5056
RCR5056
Intermolecular hydrogen transfer reactions as key stages in the catalytic cracking: achievements and outlook
Abstract
The review summarizes and critically analyzes the results of exploratory and basic studies carried out mainly in the last 10 years concerning the mechanism and role of hydrogen transfer reactions in hydrocarbon conversion processes. A discussion addresses the established views on the regularities of these reactions (mainly involving hydrogen–hydrogen, carbon–carbon and carbon–hydrogen bonds) in various systems containing cations of d-, p - and s-elements. The features of intermolecular hydrogen transfer reactions involved in the zeolite-catalyzed cracking of hydrocarbons are considered. Data on the development of compositions and investigation of properties of modern zeolite-based catalysts for hydrocarbon cracking are discussed. The attention is focused on the role of intermolecular hydrogen transfer in this process, especially in the transformations of heteroatomic compounds. Regarding zeolite compositions, the main attention is paid to the influence of the acid site distribution on the zeolite surface on the hydrogen transfer reactions and the role of extra-framework aluminium species and added modifier cations in these processes. The results of studies of hydrogen transfer by model calculations and by drawing analogies are presented. It is demonstrated that intermolecular hydrogen transfer reactions must be taken into account while addressing problems of improving the cracking catalysts and creating catalytic compositions for joint processing of sulfur, nitrogen and oxygen compounds together with hydrocarbons in the catalytic cracking. The bibliography includes 249 references.
Uspehi himii. 2023;92(1):RCR5065
RCR5065
Di- and polyazides. Synthesis, chemical transformations and practical applications
Abstract
The chemistry of organic di- and polyazides has been extensively developed in recent years. Methods for the synthesis of 1,1- and 1,2-diazides are diverse and include stoichiometric, catalytic, photochemical and electrochemical approaches. These organic compounds are highly reactive and are involved in a wide range of reactions, from thermal transformations to click chemistry. Of particular attention are transformations, in which one azido group undergoes intramolecular cyclization, while another azido group remains intact and can participate in further chemical transformations. Tri- and polyazides are investigated as precursors for the production of high-energy materials and the synthesis of high-molecular-weight compounds. This review addresses the methods for the synthesis of organic compounds containing two or more azido groups and their chemical transformations. Aliphatic, aromatic and heteroaromatic diazides are considered. Specific transformations characteristic of geminal and vicinal diazides, which differ from the reactions of monoazides, are described. Examples of the practical application of di-, tri- and polyazides are highlighted. The bibliography includes 355 references
Uspehi himii. 2023;92(1):RCR5066
RCR5066