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Enteroviruses are non-enveloped viruses of Enterovirus genus, Picornaviridae family, causing a variety of human diseases: from acute respiratory and intestinal infections to more severe pathologies including poliomyelitis, encephalitis, myocarditis, pancreatitis. Currently, no approved direct-acting antiviral drugs for treatment of enterovirus infections exists, whereas vaccination is available only for prevention of poliomyelitis and enterovirus 71 infection. Therefore, it is promising to conduct a search for inhibitors of enteroviruses life cycle in drug development to treat enterovirus infections. Here, antiviral properties of stable free radicals, verdazyls, and their precursors, leucoverdazyls, were investigated. It has been shown that leucoverdazyls vs verdazyls increased the survival of permissive cell culture infected with coxsackievirus. The activity range of the lead leucoverdazyl against RNA-containing and DNA-containing human viruses (in the viral yield reduction assay) and its proposed mechanism of action (time of addition assay) was studied. The lead compound suppressed reproduction of group B enteroviruses in vitro, with modest activity against influenza A virus and no activity against herpes virus type 1 and adenovirus type 5. The maximum decrease in viral titers was observed upon its addition to infected cells during early and middle stages of the virus life cycle. Thus, we concluded that the studied compound has a pronounced inhibitory activity against group B enteroviruses not belonging to the class of capsid binder inhibitors, without virucidal properties. Previously, we described antioxidant properties of leucoverdazyls. It is known that many viral infections are accompanied by production of reactive oxygen species and oxidative stress, and some compounds with antioxidant properties exhibit antiviral potential. Targeted chemical modifications of leucoverdazyls and further studies of leucoverdazyl mechanism of action as well as in vivo animal studies are needed. However, the results obtained may be useful for future development of new antiviral drugs to treat enteroviral infections.

Extensive research on the synthesis and application of benzazine derivatives for electronic devices, luminescent elements, photoelectric conversion elements, and image sensors has been published recently. This review covers article data obtained within the period 2012 – 2018 on the synthesis and optical properties of functionalized quinolines, quinoxalines and quinazolines. Arylvinyl, arylethynyl and (het)aryl derivatives of these benzazines, their photoluminescence and photoisomerization are discussed. Examples of photosensitive annelated, oligo- and polymeric benzazines and also coordination compounds with benzazine ligands are reviewed. The bibliography includes 267 references.

Novel 3-phenyl/pyridinyl-trans-2-(aryl/heteryl)vinyl-3H-quinazolin-4-ones 3a,b, 4a, 5a, 7a and their 6,7-difluoro de- rivatives 3c,d, 4b, 5b, 7b have been obtained by condensation of the correspondent 2-methylquinazolin-4-ones 1, 6 with aromatic (heterocyclic) aldehydes in the presence of ZnCl2 (AcONa) or by the reaction of 2-methyl-3,1-benzoxazin-4- ones 2 with the Shiff bases. Effects of aryl(heteryl) substituents on photophysical properties of (aryl/heteryl) quinazolinylethenes have been studied.

Complexes ZnL2 with novel fluorinated benzazines as tridentate ligands (HL = 6,7-difluoroquinoxalinand 6,7-difluoroquinolincarboxalidin-2-aminophenol) have been prepared. The photophisical properties of the ligands and the complexes has been studied.

A synthetic approach to 2-methyl-6,7-difluoro-8-hydroxyquinoline, a key intermediate, has been developed. 6,7-Difluoro derivative of 2-styryl substituted 8-hydroxyquinoline and its Zn(II) complex have been obtained. Effects of fluorine atoms in the benzene ring on photophysical properties of 2-styryl-8-hydroxyquinolines and their Zn(II) complexes have been studied. © 2013 Elsevier B.V.

A versatile pathway for the synthesis of 7-cycloalkylimino substituted 3-amino-6-fluoro-2-methyl-3H-quinazolin-4-ones from 4,5-difluoroanthranylic acid has been advanced. Nucleophilic amination-defluorination reaction of the 6,7-difluoro derivative of 3-amino-2-methyl-3H-quinazolin-4-one has been established to occur at position 7, as shown by X-ray crystallographic analysis. © 2012 Elsevier B.V.

The current data on the structure of formazans in crystals and in solutions are considered and some problems of tautomeric and conformational equilibria are discussed. Some novel classes of formazans synthesised over the past decade are presented. The results of structural studies of formazan complexes with various types of metal coordination are generalised. Examples of synthesis of formazan-containing polymers are given. Special emphasis is placed on analytical and practical applications of formazan derivatives. The bibliography includes 155 references. © 2006 Russian Academy of Sciences and Turpion Ltd.