Design and Antioxidant Properties of Bifunctional 2-Imidazole-Derived Phenolic Compounds-A New Family of Effective Inhibitors for Oxidative Stress-Associated Destructive Processes.

The synthesis of inhibitors for oxidative stress-associated destructive processes based on 2-imidazole-derived phenolic compounds affording the bifunctional 2-imidazole-derived phenolic compounds in good-to-excellent yields was reported. In particular, a series of bifunctional organic molecules of the 5-aryl-2-imidazole family of various architectures bearing both electron-donating and electron-withdrawing substituents in the aryl fragment along with the different arrangements of the hydroxy groups in the polyphenol moiety, namely derivatives of phloroglucinol, pyrogallol, hydroxyquinol, including previously unknown water-soluble molecules, were studied. The structural and antioxidant properties of these bifunctional 5-aryl-2-imidazoles were comprehensively studied.

Metal-Free C-H/C-H Coupling of 2-Imidazole 1-Oxides with Polyphenols toward Imidazole-Linked Polyphenolic Compounds.

The methodology of nucleophilic substitution of hydrogen (S) was successfully applied as a convenient synthetic tool to afford azaheterocyclic derivatives of phenols of various architectures. A series of 26 novel imidazole-linked polyphenolic compounds were first prepared in 72-95% yields through the direct metal-free C-H/C-H coupling of polyphenols with 2-imidazole 1-oxides. Comprehensive studies on the reaction condition optimization, scope, and limitations enabled the development of a straightforward method toward novel bifunctional derivatives bearing both phenolic and imidazole scaffolds of particular interest in the design of challenging molecules for versatile applications in medicinal chemistry and materials science.

Recent advances in the functionalization of polyfluoro(aza)aromatics C-C coupling strategies.

Polyfluoro(aza)aromatic compounds are of interest in various fields of practical applications, such as medicinal and agrochemistry, materials science and advanced technologies. The C-C coupling reactions are known to be a promising synthetic tool to create challenging fluorinated molecules of diverse architectures. In this review, we have summarized the recent advances in the functionalization of polyfluoro(aza)aromatics via both transition metal-catalyzed and metal-free C-C coupling reactions for the period from 2006 to the beginning of 2021.

-functionalization of calix[4]arene with 1,3,7-triazapyrene in the design of novel fluorophores with the dual target detection of Al and Fe cations.

A -functionalization strategy has successfully been applied to the synthesis of novel 1,3,7-triazapyrene derivatives of calixarenes. The key synthetic step in these transformations providing the direct C-C bond formation is nucleophilic substitution of hydrogen (S ) in 1,3,7-triazapyrene. General photophysical characteristics for these macrocyclic compounds, as well as features in emission properties upon addition of various metal cations have been elaborated.

Transition-Metal-Free C-H/C-Li Coupling of Nonaromatic 2-Imidazole 1-Oxides with Pentafluorophenyl Lithium in the Design of Novel Fluorophores with Intramolecular Charge Transfer Effect.

Methodology of nucleophilic substitution of hydrogen (S) was first applied for the direct modification of nonaromatic 2-imidazoles to afford novel polyfluoroarylated azaheterocycles. Scope, tolerance for these transition-metal-free C-H/C-Li coupling reactions, and photophysical properties for the novel 4-(perfluorophenyl)-5-aryl-2-imidazoles were comprehensively studied. In particular, some of the obtained perfluoroaryl-substituted 2-imidazoles were found to be of particular interest as promising push-pull fluorophore systems in the design of fluorometric sensor materials due to the effect of intramolecular charge transfer.

Synthesis of Functionalized Pyrazin-2(1 H)-ones via Tele-Nucleophilic Substitution of Hydrogen Involving Grignard Reactants and Electrophiles.

The reaction of 6-chloro-1-methylpyrazin-2(1 H)-one with Grignard reactants followed by quenching with different electrophiles gave access to a variety of 3,6-difunctionalized 1-methylpyrazin-2(1 H)-ones. This regioselective three-component reaction represents the first example of a tele-nucleophilic substitution of hydrogen (S) in which the anionic σ adduct is quenched by electrophiles (other than a proton) before elimination takes place. Quenching the reaction with iodine (I) or bromine (Br) provides an alternative reaction pathway, yielding a 3-functionalized 6-chloro-1-methylpyrazin-2(1 H)-one or 5-bromo-6-chloro-1-methylpyrazin-2(1 H)-one, respectively.

Metal-free C-H functionalization of 2H-imidazole 1-oxides with pyrrolyl fragments in the design of novel azaheterocyclic ensembles.

The methodology of direct C(sp)-H functionalization has for the first time been applied as an efficient and advanced approach to carry out C-H/C-H coupling of 2H-imidazole 1-oxides and pyrroles. The atom-economical method used does not require either any auxiliary group in the starting substrates, or catalysis by transition metals. As a result, a number of novel 1H-pyrrol-2-yl-2H-imidazoles, that are particularly of interest in the design of bioactive molecules, have been prepared under mild conditions and in good to excellent yields.