Diels–Alder Cycloadditions of Bio-Derived Furans with Maleimides as a Sustainable «Click» Approach towards Molecular, Macromolecular and Hybrid Systems

This mini-review highlights the recent research trends in designing organic or organic-inorganic hybrid molecular, biomolecular and macromolecular systems employing intermolecular Diels–Alder cycloadditions of biobased, furan-containing substrates and maleimide dienophiles. The furan/maleimide Diels–Alder reaction is a well-known process that may proceed with high efficiency under non-catalytic and solvent-free conditions. Due to the simplicity, 100% atom economy and biobased nature of many furanic substrates, this type of [4+2]-cycloaddition may be recognized as a sustainable “click” approach with high potential for application in many fields, such as fine organic synthesis, bioorganic chemistry, material sciences and smart polymers development.

Catalytic Oxidations with Meta-Chloroperoxybenzoic Acid (m-CPBA) and Mono- and Polynuclear Complexes of Nickel: A Mechanistic Outlook

Selective catalytic functionalization of organic substrates using peroxides as terminal oxidants remains a challenge in modern chemistry. The high complexity of interactions between metal catalysts and organic peroxide compounds complicates the targeted construction of efficient catalytic systems. Among the members of the peroxide family, m-chloroperoxybenzoic acid (m-CPBA) exhibits quite complex behavior, where numerous reactive species could be formed upon reaction with a metal complex catalyst. Although m-CPBA finds plenty of applications in fine organic synthesis and catalysis, the factors that discriminate its decomposition routes under catalytic conditions are still poorly understood. The present review covers the advances in catalytic C–H oxidation and olefine epoxidation with m-CPBA catalyzed by mono- and polynuclear complexes of nickel, a cheap and abundant first-row transition metal. The reaction mechanisms are critically discussed, with special attention to the O–O bond splitting route. Selectivity parameters using recognized model hydrocarbon substrates are summarized and important factors that could improve further catalytic studies are outlined.

Selective catalytic hydrogenation of the triple bond in acetylenic alcohols in a microcapillary reactor for fine organic synthesis

The purpose of this work is to present our latest achievements in the design, synthesis and development of a new catalytic microreactor for the processes of selective and continuous synthesis of substances with added value that are used in fine organic synthesis and pharmaceutical industries. In this advanced device, metal nanoparticles are embedded in mesoporous materials, which are deposited in the form of highly active and selective catalytic films on the walls of capillary microchannels with diameters of 220 and 530 μm. In such microreactor systems, there is no subsequent separation of the catalyst, which facilitates continuous operation. Potentially the most stable coatings are crystalline or amorphous titanium dioxide based metal oxides synthesized by the sol-gel method and containing embedded catalytically active polymetallic nanoparticles. The catalytic properties and operational stability of capillary microreactors were investigated at atmospheric pressure and compared with conventional industrial batch reactors. The developed Pd50Zn50 /TiO2 coating showed a higher activity (1.5 gMBE·gPd–1·s–1) and selectivity (96.7 %) in comparison with the coatings described earlier in the literature and with the industrial Lindlar catalyst, and retained high catalytic performance after 88 hours of reaction.

α-Functionally Substituted α,β-Unsaturated Aldehydes as Fine Chemicals Reagents: Synthesis and Application

α-Functionalized α,β-unsaturated aldehydes is an important class of compounds, which are widely used in fine organic synthesis, biology, medicine and pharmacology, chemical industry, and agriculture. Some of the 2-substituted 2-alkenals are found to be the key metabolites in plant and animal cells. Therefore, the development of efficient methods for their synthesis attracts the attention of organic chemists. This review focusses on the recent advances in the synthesis of 2-functionally substituted 2-alkenals. The approaches to the preparation of α-alkyl α,β-unsaturated aldehydes are not included in this review.

ENZYME BIOCATALYSIS IN ORGANIC SYNTHESIS

The factor that makes enzyme biocatalysts for organic synthesis both fascinating and challenging from a scientific standpoint is the field's higher interdisciplinarity, and which necessitates expertise from a wide range of disciplines, including microbiology, organic synthesis, molecular biology, genetics, and reaction engineering. Enzymes can now carry out a wide variety of organic reactions, including hydrolytic reactions, redox reactions, and C-C bond formations, with higher performance. Enzyme catalysis has also evolved into a widely used manufacturing technology in the chemical industry, especially in the fields of fine organic chemicals and pharmaceuticals. More advances in molecular modeling for enzyme-catalysis syntheses are expected, allowing for a greater number of biocatalytic techniques based on the enzymes that have been optimized or engineered by rationalized protein engineering. The organic chemists mostly have successfully used these custom-made biocatalysts (the isolated pure enzymes, the recombinant genetically modified microorganisms, also known as the designer cells), an important milestone in the enzyme catalysis process in organic synthesis is into generally accepted synthetic technology for academia as well as industries.

Amino-1,2,4-triazoles as a raw material for the fine organic synthesis industry (review).

AMINO-1,2,4-TRIAZOLES AS A RAW MATERIAL FOR THE FINE ORGANIC SYNTHESIS INDUSTRY (REVIEW) © V.N. Nazarov, PhD in technical sciences, D.V. Miroshnichenko, Doctor of Technical Sciences, A.A. Ivakh, B.V. Uspensky (NTU "Kharkov Polytechnic Institute", 61002, Kharkov, Kirpicheva st., 2, Ukraine) The review summarizes the information on the industrial use of 3- and 4-amino-1,2,4-triazoles - the basic raw material for the industry of fine organic synthesis. 3 and 4-substituted amino-1,2,4-triazoles have been used for a long time in the production of agricultural products, pharmaceuticals, dyes, high-energy materials, and anti-corrosion additives. Less well known is their use for the production of analytical reagents, flotation reagents, as well as for the production of heat-resistant polymers, products with fluorescent properties and ionic liquids, which are used in applied sciences, biotechnology, energy, and chemistry. The purpose of this communication is to consider in detail the participation of 3- and 4-amino-1,2,4- triazoles in the production and use of various agricultural and medical products. Descriptions and schemes of chemical reactions of existing production methods for the synthesis of 3- and 4-amino-1,2,4-triazoles, as well as some methods of obtaining these substances in laboratory conditions, are given. The two main areas of use of these amines and their derivatives: agriculture and medicine have been highlighted. It is shown that one of the most well-known branches of widespread use of 3- and 4- amino-1,2,4-triazoles in agriculture is the production of plant protection products. On the basis of these substances, the mass production of various insecticides, fungicides, plant growth regulators, retardants (means for suppressing the growth of stems and shoots), inhibitors of nitrification of nitrogen fertilizers is organized. The use of these amines in medicine consists in the production of known drugs on their basis, such as furazonal (has a pronounced antimicrobial effect, is effective against Staphylococcus aureus, dysentery bacteria, salmonellosis), thiotriazoline and cardiotril (cardiological drugs with anti-ischemic and membrane stabilizing effects) (platelet growth factor antagonist). Keywords: amino-1,2,4-triazoles, production, raw materials for synthesis, pesticides, pharmaceuticals. Corresponding author V.N. Nazarov, е-mail: р[email protected]

Environmental factors shaping assemblages of ostracods (Crustacea: Ostracoda) in springs situated in the River Krąpiel valley (NW Poland)

We investigated the ostracod assemblage structure in springs of a small lowland River Krąpiel valley. Environmental factors and the potential of ostracods as indicators of spring type were analysed. The analysis involved the type of spring, substrate, physicochemical parameters, and the river valley's hydrological status as environmental factors. A total of thirty ostracod species were recorded. The average count of ostracod individuals in a sample amounted to 100. The assemblages were dominated by juvenile Candona sp., juvenile Psychrodromus sp., Cypria ophtalmica, and Cypridopsis vidua. The spring species accounted for less than 1% of the individual counts, except for juvenile Psychrodromus sp. with 21% and Eucypris pigra with 4%. The average number of taxa per spring was 5. The ostracod assemblages were significantly influenced by limnocrene springs, spring flooding by the river overflow, the presence of coarse leaf litter, the presence of fine organic matter, a high content of NH4 as well as by BOD5, conductivity, pH, Fe, the river habitat modification index (RHM), the habitat modification score (HMS), and the river habitat quality (RHQ). The habitat conditions for the spring species appeared to be enhanced by the domination of mineral substrate over fine particulate organic matter, an elevated pH, the presence of leaf-derived organic matter, and the absence of flooding by the river. The spring species showed no association with the Krąpiel valley hydrological factors.