Coordination behavior of benzimidazole, 2-substituted benzimidazoles and benzothiazoles, towards transition metal ions (original) (raw)
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Chemistry and Applications of Benzimidazole and its Derivatives
2019
This chapter describes contemporary strategies for selective catalytic intermolecular functionalization of the benzimidazole scaffold. Functionalization at nitrogen and position C-2 is well developed employing copper, palladium, rhodium, nickel, and cobalt catalysis. Direct CH activation is the predominant approach to C-2 functionalization. Nickel-based catalysts can activate CO bonds in conjunction with C-H activation at benzimidazole which grants access to a very broad range of phenols and enols as convenient functionalization precursors in this chemistry. The remaining carbon positions of benzimidazoles are typically functionalized via a sequential halogenation/coupling strategy to ensure selectivity. A key success factor in enabling these chemistries has been the fine-tuning of catalystligand combinations.
Journal of Coordination Chemistry, 2018
Dedicated to Dan Meyerstein in recognition of his contribution to inorganic chemistry. Spectroscopic and single crystal X-ray diffraction studies of coordination compounds of Co II , Ni II , Zn II and Pd II with phenylsulfonyl imidazole and benzimidazole derivatives (2-mfsiz, 2-mfsbz) were performed. The relevance of non-covalent interactions on the stabilization of intra and intermolecular arrangements in the ligands and their coordination compounds was investigated. The imidazole 2-mfsiz ligand presents two enantiomeric conformers, where the ethylphenylsulfone moiety stabilizes intermolecular lone pair••• (S-O••• (phe)) and H••• contacts, while its tetrahedral coordination compounds, [M(2-mfsiz) 2 X 2 ] (M 2+ = Co, Ni, Zn; X = Cl, Br) showed intramolecular lone pair••• interactions (S-O••• (iz)). On the other hand, compounds [Cu 2 (2-mfsiz) 2 (µ 2-AcO) 4 ] and trans-[Pd(2-mfsiz) 2 Cl 2 ] do not present lone pair••• interactions due to the metal ion geometry (square base pyramidal or square planar), which leads to formation of (iz) ••• (phe) interactions. For the benzimidazole ligand 2-mfsbz, an intramolecular, H (phe) ••• (bz) contact was observed, remaining in its tetrahedral and octahedral coordination compounds, [M(2-mfsbz) 2 X 2 ] (M 2+ = Co, Zn; X = Cl, Br, NO 3). This interaction limits the free rotation of the ethylphenylsulfone moiety for stabilization of an intermolecular lone pair••• interaction (S-O:••• (iz)). The dimeric [Zn 2 (2-mfsiz) 2 (µ 2-AcO) 4 ] compound has a (bz) ••• (phe) contact. Theoretical calculations confirmed the non-covalent interactions in the ligands and their coordination compounds.
Benzimidazole: An Important Biological Heterocyclic Scaffold
Journal of Current Pharma Research, 2014
Various heterocyclic scaffolds have drawn special attention of medicinal chemists and hence, extensive efforts are being carried out in search of lead molecules related to it. Benzimidazole is an important pharmacophore owing to its inherent properties and therapeutic actions. These exhibit many biological activities like anticancer, anticonvulsant, antiHIV, antimicrobial and many more. Such biological applications of benzimidazole derivatives have attracted attention and stimulated new search for its novel derivatives with improved biological activities and these are being extensively studied. The present review includes rigorous literature survey on the search of biologically active benzimidazole ring linked and fused with other heteroaromatic systems.
A Comprehensive Study of N-Butyl-1H-Benzimidazole
Molecules
Imidazole derivatives have found wide application in organic and medicinal chemistry. In particular, benzimidazoles have proven biological activity as antiviral, antimicrobial, and antitumor agents. In this work, we experimentally and theoretically investigated N-Butyl-1H-benzimidazole. It has been shown that the presence of a butyl substituent in the N position does not significantly affect the conjugation and structural organization of benzimidazole. The optimized molecular parameters were performed by the DFT/B3LYP method with 6-311++G(d,p) basis set. This level of theory shows excellent concurrence with the experimental data. The non-covalent interactions that existed within our compound N-Butyl-1H-benzimidazole were also analyzed by the AIM, RDG, ELF, and LOL topological methods. The color shades of the ELF and LOL maps confirm the presence of bonding and non-bonding electrons in N-Butyl-1H-benzimidazole. From DFT calculations, various methods such as molecular electrostatic po...
Benzimidazole: An important Scaffold in Drug Discovery
Asian Journal of Pharmacy and Technology, 2015
The use heterocyclic compounds in field of medicinal chemistry is increasing day by day due to various reasons like heterocyclic compounds are included in the structure of many biochemical materials, which are essential for life for e.g. nucleic acid, many naturally occurring pigments like chlorophyll, vitamins and antibiotics. Modern society is also dependent on synthetic heterocycles for use as drugs, pesticides and dyes. The work embodied in this article relates to Benzimidazole as it is a versatile heterocycle possessing a wide spectrum of biological activities like antihelminthic, antifungal, anti-allergic, antimicrobial, antiviral and antineoplastic activities. Although it comprising nearly one quarter of top hundred selling drugs but due to problems like resistance, toxicity, there is a need for minor modification of existing agents and to design novel agents which incorporate benzimidazole as pharmacophoric handle which act against new targets. This review highlights the importance of Benzimidazole in medicinal world along with a few examples of clinically used drugs. Additionally review of some of the work concerning benzimidazole reported in the recent literature has also been provided.
Journal of Molecular Structure, 2020
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Structural Chemistry, 2007
Novel cyano-substituted benzimidazole derivatives 3 and 4 were synthesized from 4-N,N-dimethylamino-benzaldehyde and 2-cyanomethyl-benzimidazole. 2-(1H-benzimidazol-2-yl)-3-(4-N,N-dimethylamino-phenyl)acrylonitrile hydrochloride monohydrate 4 has been studied by 1 H and 13 C NMR, IR, MS, UV/Vis and fluorescence spectroscopy and confirmed by X-ray crystal structure analysis. The interaction of 4 with ct-DNA has also been investigated by fluorescence spectroscopy and melting temperature determination experiment. According to the emission spectra recorded in the absence and presence of ct-DNA at different ratios r ([compound]/[polynucleotide]), 4 showed marked decrease in the fluorescence intensity and very strong hypochromic effect. Melting temperature experiment showed weak stabilization of double helix. To determine binding mode of 4, other additional experiments are necessary. The molecules of 4 are almost planar with the dihedral angle between benzimidazole and phenyl rings of 6.99(6)°. The protonation of nitrogen atom of benzimidazole ring is followed by p-electrons delocalization in the C N N region resulting in C-N bond distances equality [1.341(2) and 1.337(2) Å ]. Both NH groups of benzimidazole ring form intermolecular hydrogen bonds, one with the oxygen atom of water molecule [NÁÁÁO 2.689(2) Å ] and the other with Clion (NÁÁÁCl -3.051(1) Å ).