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.

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]

Synthesis of Aromatic Diketoximes and their Complexes with Nickel Salts

The diketoximes of 4,4'-diacetyldiphenyl oxide and 4,4'-diacetyldiphenyl sulfide were synthesized, the possibility of their use for the synthesis of simple and complex polyesters and polypyrroles, as well as the ability to complex with nickel salts. Organic chemistry used oximes in the 19th century, afterward, as an analytical reagent in the 20th century. Currently, oximes are superior to carbonyl compounds and alcohols in the variety of reactions and the widespread use in synthetic chemistry. Oximes easily turn into other classes of organic compounds – amines, cyano and nitro compounds, carbonyl compounds, heterocyclic compounds, including pyrroles, imidazoles, pyridines, they can be used as suitable compounds with salts of Cu (II), Ni (II), Zn (II), Cd (II), and Co (II). Oximes with complex heterocyclic and aromatic substituents are used as intermediates in fine organic synthesis. It should be noted that oximes have a wide spectrum of biocidal action and are used as anti-inflammatory, antiviral, antimicrobial agents, insecticides. Their versatile biological activity is considered in the preparation of antidepressant, sedative, vasodilator and other drugs [1].

Oxidation of Organic Substrates in Two-рhase Liquid Systems in the Presence of Tungsten Peroxo Complexes to Obtain Carboxylic Acids

The paper presents a brief review of the studies on the oxidation of various organic compounds with hydrogen peroxide performed by the authors at the Boreskov Institute of Catalysis SB RAS. Main catalytic systems for the production of carboxylic acids, which are the marketable products for industry and fine organic synthesis, under the conditions of interphase catalysis are considered. It was shown that the use of pre-synthesized catalytic complexes with the general formula Q3{PO4[WO(O2)2]4} improves the process performance, for example, increases the product yield, decreases the reaction time and lowers the catalyst concentration in comparison with the processes where the catalyst precursors are introduced in the reaction medium simultaneously with other reagents, and the active complex is formed in situ.

Gas mixture composition control in fine organic synthesis

Fine organic synthesis includes a large number of stages. All its stages require determining the small quantities of impurities for initial and intermediate synthesis products. Fine organic synthesis is a complex process requiring automation. To automate the synthesis products’ control device it is necessary to use the modern physico-chemical methods, which perform continuous measurements with high speed. This paper describes the hardware implementation of a device, based on infrared absorption analysis method. The absorption methods of substance composition analysis are based on the absorption of sounding radiation by the analysed component. The strength of the probing radiation passing through the mixture changes slightly at the small concentrations of the analysed component. Therefore, there is a problem of measuring small changes of a large signal. The absorption method of substance composition analysis can be used for analysis the composition of mixtures of gaseous organic substances. It enables to scan the optical frequency of the probe radiation by changing the angle of the interference filter. The proposed equipment allows determining the concentration of substances by overlapping their absorption spectra of infrared radiation.

Synthesis of 5-hydroxy-10-R-benzo[a]phenazine-12-oxides by cyclization of 2-arylamino-1,4-naphthoquinone-1-oximes under the action of nitrating mixture

The synthesis of рolycyclic quinoid compounds, which exhibit a wide range of biological activity is one of the most promising and actively developing areas of the fine organic synthesis. Heterocyclic compounds including those that can be donors of nitrogen oxide NO occupy a special place among biologically active structures. These substances include a number of N-oxides, e.g., 1,2-diazet-1,2-dioxides, furoxanes and their benzo analogs, and N,N′-pyrazole dioxides. The reason for the high biological activity of N-oxides of nitrogenous heterocycles, which cannot easily generate nitrogen oxide NO may be their oxidative properties. Thus, N-oxides of nitrogenous heterocycles are of interest due to their high biological activity. We have developed an approach to the synthesis of 5-hydroxy-10-R-benzo[a]phenazine-12-oxides that contain the N-oxide fragment, which makes these compounds promising for studying their biological activity. We have demonstrated that the treatment of 2-arylamino-1,4-naphthoquinones with hydroxylamine in ethanol at 50-60 °С leads to selective oximation at position 1 and the formation of 2-arylamino-1,4-naphthoquinone-1-oximes. It has been shown that the interaction of 2-arylamino-1,4-naphthoquinone-1-oximes with the nitrating mixture in acetic acid results in the formation of 5-hydroxy-10-R-benzo[a]phenazine-12-oxides. Our work is a continuation of the study on the interactions of 2-arylamino-1,4-naphthoquinones and 4-arylamino-1,2-naphthoquinones with nitrosylsulfuric acid in acetic acid and the interaction of 2-alkyl(benzyl)amino-1,4-naphthoquinones with nitrosylsulfuric acid or nitrating mixture in acetic acid. The former reactions lead to the formation of 3-R-benzo[b]phenazine-6,11-dione-5-oxides and 9-R-benzo[a]phenazine-5,6-dion-7-oxides, respectively. The latter reaction leads to the formation of 2-alkyl(aryl)naphtho[2,1-d][1,3]oxazole-4,5-dione-4-oximes and 2-alkyl(aryl)-1-hydroxy-1H-naphtho[2,3-d]imidazole-4,9-dione as main products.