NUCLEOPHILIC SUBSTITUTION OF NITRO GROUP IN 1-METHYL- 5-NITRO-1,2,4-TRIAZOLE BY DIAMINOGLYOXIME

Изучен процесс взаимодействия 1-метил-5-нитро-1,2,4-триазола с многоцентровым бифункциональным О-нуклеофилом – диаминоглиоксимом. Показано, что исходный субстрат вступает в реакцию SNipso-замещения нитрогруппы с гидроксильными группами О-нуклеофила с образованием биологически активного соединения, объединяющего в единой молекуле фармакофорные фрагменты различного типа – 1,2,4-триазоловые гетероциклы и NH2-группы. Процесс сопровождается конкурентными реакциями образования триазолона и продукта его дальнейшего взаимодействия с исходным субстратом. С помощью веб-ресурса PASS Online осуществлен компьютерный скрининг, показано, что исходный субстрат и продукты реакции могут выступать потенциальными фармацевтическими субстанциями. The reaction between 1-methyl-5-nitro-1,2,4-triazome and a concerted bifunctional О-nucleophile – diaminoglyoxime was explored herein. The starting substrate was shown to engage into the SNipso-substitution of the nitro group by the О-nucleophile hydroxyls to furnish a bioactive compound whose single molecule combines different-type pharmacophoric moieties – 1,2,4-triazole heterocycles and NH2groups. The process came amid competitive reactions to form triazolone and a product from its subsequent reaction with the starting substrate. The PASS Online web-resource was used to perform computer-aided screening, demonstrating that the starting substrate and the reaction products can serve as potential pharmaceutical substances.

4,6-Dichloro-5-Nitrobenzofuroxan: Different Polymorphisms and DFT Investigation of Its Reactivity with Nucleophiles

This research focuses on the X-ray structure of 4,6-dichloro-5-nitrobenzofuroxan 1 and of some of its amino derivatives (4a, 4e, 4g, and 4l) and on DFT calculations concerning the nucleophilic reactivity of 1. We have found that by changing the solvent used for crystallization, it is possible to obtain 4,6-dichloro-5-nitrobenzofuroxan (1) in different polymorphic structures. Moreover, the different torsional angles observed for the nitro group in 1 and in its amino derivatives (4a, 4e, 4g, and 4l) are strictly dependent on the steric hindrance of the substituent at C-4. DFT calculations on the course of the nucleophilic substitution confirm the role of the condensed furoxan ring in altering the aromaticity of the carbocyclic frame, while chlorine atoms strongly influence the dihedral angle and the rotational barrier of the nitro group. These results corroborate previous observations based on experimental kinetic data and give a deep picture of the reaction with amines, which proceeds via a “non-aromatic” nucleophilic substitution.

An Efficient Approach to 2-CF3-Indoles Based on ortho-Nitrobenzaldehydes

The catalytic olefination reaction of 2-nitrobenzaldehydes with CF3CCl3 afforded stereoselectively trifluoromethylated ortho-nitrostyrenes in up to 88% yield. The reaction of these alkenes with pyrrolidine permits preparation of α-CF3-β-(2-nitroaryl) enamines. Subsequent one pot reduction of nitro-group by Fe-AcOH-H2O system initiated intramolecular cyclization to afford 2-CF3-indoles. Target products can be prepared in up to 85% yields. Broad synthetic scope of the reaction was shown as well as some followed up transformations of 2- CF3-indole.

Surface Functionalization of Boron-Carbon BС5 Nanotubes by a Nitro Group As a Sensor Device Element: Theoretical Research

The problem of modification of boron-carbon nanotubes (BCNT) by functional groups is relevant in connection with the intensive development of the nano industry, in particular, nano- and microelectronics. For example, a modified nanotube can be used as an element of a sensor device for detecting microenvironments of various substances, in particular metals included in salts and alkalis. The paper discusses the possibility of creating a high-performance sensor using single-layer boron-carbon nanotubes as a sensitive element, the surface of which is modified with a functional nitro group -NO2. Quantum-chemical studies of the process of attaching a nitro group to the outer surface of a single-layer boron-carbon nanotube (BCNT) of type (6, 6) were carried out, which proved the possibility of modifying the BCNT and the formation of a bond between the group -NO2 and the carbon atom of the surface of the nanotube. The results of computer simulation of interaction of surface-modified boron-carbon nanotube with alkali metal atoms (lithium, sodium, potassium) are presented. The sensory interaction of the modified boron-carbon nanosystem with the selected metal atoms was investigated, which proved the possibility of identifying these atoms using a nanotubular system that can act as an element of the sensor device. When reacting with alkali metal atoms in the “BСNT+NO 2” complex, the number of basic carriers increases, due to the transfer of electron density from metal atoms to modified BСNT. The results presented in this paper were obtained using the molecular cluster model and the calculated DFT method with exchange-correlation functionality B3LYP (valence-split basis set 6-31G).

Nitro-Deficient Niclosamide Confers Reduced Genotoxicity and Retains Mitochondrial Uncoupling Activity for Cancer Therapy

Niclosamide is an oral anthelmintic drug, approved for use against tapeworm infections. Recent studies suggest however that niclosamide may have broader clinical applications in cancers, spurring increased interest in the functions and mechanisms of niclosamide. Previously, we reported that niclosamide targets a metabolic vulnerability in p53-deficient tumours, providing a basis for patient stratification and personalised treatment strategies. In the present study, we functionally characterised the contribution of the aniline 4′-NO2 group on niclosamide to its cellular activities. We demonstrated that niclosamide induces genome-wide DNA damage that is mechanistically uncoupled from its antitumour effects mediated through mitochondrial uncoupling. Elimination of the nitro group in ND-Nic analogue significantly reduced γH2AX signals and DNA breaks while preserving its antitumour mechanism mediated through a calcium signalling pathway and arachidonic acid metabolism. Lipidomics profiling further revealed that ND-Nic-treated cells retained a metabolite profile characteristic of niclosamide-treated cells. Notably, quantitative scoring of drug sensitivity suggests that elimination of its nitro group enhanced the target selectivity of niclosamide against p53 deficiency. Importantly, the results also raise concern that niclosamide may impose a pleiotropic genotoxic effect, which limits its clinical efficacy and warrants further investigation into alternative drug analogues that may ameliorate any potential unwanted side effects.