Substituted 2,5'-Bi-1H-benzimidazoles: topoisomerase I inhibition and cytotoxicity

A benzimidazole derivative exhibiting antitumor activity blocks EGFR and HER2 activity and upregulates DR5 in breast cancer cells

Aberrant expression or function of epidermal growth factor receptor (EGFR) or the closely related human epidermal growth factor receptor 2 (HER2) can promote cell proliferation and survival, thereby contributing to tumorigenesis. Specific antibodies and low-molecular-weight tyrosine kinase inhibitors of both proteins are currently in clinical trials for cancer treatment. Benzimidazole derivatives possess diverse biological activities, including antitumor activity. However, the anticancer mechanism of 5a (a 2-aryl benzimidazole compound; 2-chloro-N-(2-p-tolyl-1H-benzo[d]imidazol-5-yl)acetamide, C₁₆H₁₄ClN₃O, MW299), a novel 2-aryl benzimidazole derivative, toward breast cancer is largely unknown. Here, we demonstrate that 5a potently inhibited both EGFR and HER2 activity by reducing EGFR and HER2 tyrosine phosphorylation and preventing downstream activation of PI3K/Akt and MEK/Erk pathways in vitro and in vivo. We also show that 5a inhibited the phosphorylation of FOXO and promoted FOXO translocation from the cytoplasm into the nucleus, resulting in the G1-phase cell cycle arrest and apoptosis. Moreover, 5a potently induced apoptosis via the c-Jun N-terminal kinase (JNK)-mediated death receptor 5 upregulation in breast cancer cells. The antitumor activity of 5a was consistent with additional results demonstrating that 5a significantly reduced tumor volume in nude mice in vivo. Analysis of the primary breast cancer cell lines with HER2 overexpression further confirmed that 5a significantly inhibited Akt Ser473 and Bad Ser136 phosphorylation and reduced cyclin D3 expression. On the basis of our findings, further development of this 2-aryl benzimidazole derivative, a new class of multitarget anticancer agents, is warranted and represents a novel strategy for improving breast cancer treatment.

An efficient aqueous phase synthesis of benzimidazoles/benzothiazoles in the presence of β-cyclodextrin

Benzimidazoles/benzothiazoles were synthesized in water under neutral conditions by the reaction of aromatic aldehydes, o-phenylenediamine/2-amino thiophenol mediated by β-cyclodextrin in high yields.

Synthesis, DNA interaction and anticancer activity of 2-anthryl substituted benzimidazole derivatives

2-Anthryl substituted benzimidazole derivatives were synthesized and anticancer activity, cellular uptake, DNA interaction and molecular docking studies have been accomplished.

Comprehensive Review in Current Developments of Benzimidazole-Based Medicinal Chemistry

The properties of benzimidazole and its derivatives have been studied over more than one hundred years. Benzimidazole derivatives are useful intermediates/subunits for the development of molecules of pharmaceutical or biological interest. Substituted benzimidazole derivatives have found applications in diverse therapeutic areas such as antiulcer, anticancer agents, and anthelmintic species to name just a few. This work systematically gives a comprehensive review in current developments of benzimidazole-based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, anti-inflammatory, analgesic agents, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial agents, and other medicinal agents. This review will further be helpful for the researcher on the basis of substitution pattern around the nucleus with an aim to help medicinal chemists for developing an SAR on benzimidazole drugs/compounds.

Synthesis, characterization, crystal structure and theoretical study of a compound with benzodiazole ring: antimicrobial activity and DNA binding

2-(Thiophen-2-yl)-1-((thiophen-2-yl)methyl)-1H-1,3-benzodiazole (HL) is synthesized and characterized by elemental analysis, UV-Vis, FT-IR, (1)H, (13)C NMR, mass spectra, scanning electron microscope (SEM) and single crystal X-ray diffraction. The crystal structure is stabilized by intermolecular CH⋯N and CH⋯π interactions. The molecular structure is also optimized at the B3LYP/6-31G level using density functional theory (DFT). The structural parameters from the theory are nearer to those of crystal, the calculated total energy of coordination is -1522.814a.u. The energy of HOMO-LUMO and the energy gap are -0.20718, -0.04314, 0.16404a.u, respectively. All data obtained from the spectral studies support the structural properties of the compound HL. The benzimidazole ring is essentially planar. The in vitro biological screening effects of the synthesized compound is tested against four bacterial and four fungal strains by well diffusion method. Antioxidant property and DNA binding behaviour of the compound has been investigated using spectrophotometric method.

Octyl 1-(5-tert-butyl-1H-pyrazol-3-yl)-2-(4-chlorophenyl)-1H-benzimidazole-5-carboxylate: complex sheets built from N-H···N, C-H···N and C-H···O hydrogen bonds

In the title compound, C29H35ClN4O2, the bond lengths provide evidence for aromatic delocalization in the pyrazole ring but bond fixation in the fused imidazole ring, and the octyl chain is folded, rather than adopting an all-trans chain-extended conformation. A combination of N-H···N, C-H···N and C-H···O hydrogen bonds links the molecules into sheets, in which the hydrogen bonds occupy the central layer with the tert-butyl and octyl groups arranged on either side, such that the closest contacts between adjacent sheets involve only the octyl groups. Comparisons are made with the supramolecular assembly in some simpler analogues.

A novel sodium iodide and ammonium molybdate co-catalytic system for the efficient synthesis of 2-benzimidazoles using hydrogen peroxide under ultrasound irradiation

The reaction of aldehydes and o-phenylenediamine for the preparation of 2-benzimidazoles has been studied using hydrogen peroxide as an oxidant under ultrasound irradiation at room temperature in this paper. The combination of substoichiometric sodium iodide and ammonium molybdate as co-catalysts, together with using small amounts of hydrogen peroxide, makes this transformation very efficient and attractive under ultrasound. Thus, a mild, green and efficient method is established to carry out this reaction in high yield.

A simple and efficient mechanochemical route for the synthesis of 2-aryl benzothiazoles and substituted benzimidazoles

An efficient, catalyst free mechanochemical route to 2-aryl benzothiazoles and both 2- and 1,2-disubstituted benzimidazoles has been developed via a simple mortar–pestle grinding method.

K10 montmorillonite clays as environmentally benign catalysts for organic reactions

This perspective summarizes the catalytic activity of K10 montmorillonite as a multifunctional catalyst for organic reactions.

Conjugation of benzylvanillin and benzimidazole structure improves DNA binding with enhanced antileukemic properties

Benzyl-o-vanillin and benzimidazole nucleus serve as important pharmacophore in drug discovery. The benzyl vanillin (2-(benzyloxy)-3-methoxybenzaldehyde) compound shows anti-proliferative activity in HL60 leukemia cancer cells and can effect cell cycle progression at G2/M phase. Its apoptosis activity was due to disruption of mitochondrial functioning. In this study, we have studied a series of compounds consisting of benzyl vanillin and benzimidazole structures. We hypothesize that by fusing these two structures we can produce compounds that have better anticancer activity with improved specificity particularly towards the leukemia cell line. Here we explored the anticancer activity of three compounds namely 2-(2-benzyloxy-3-methoxyphenyl)-1H-benzimidazole, 2MP, N-1-(2-benzyloxy-3-methoxybenzyl)-2-(2-benzyloxy-3-methoxyphenyl)-1H-benzimidazole, 2XP, and (R) and (S)-1-(2-benzyloxy-3-methoxyphenyl)-2, 2, 2-trichloroethyl benzenesulfonate, 3BS and compared their activity to 2-benzyloxy-3-methoxybenzaldehyde, (Bn1), the parent compound. 2XP and 3BS induces cell death of U937 leukemic cell line through DNA fragmentation that lead to the intrinsic caspase 9 activation. DNA binding study primarily by the equilibrium binding titration assay followed by the Viscosity study reveal the DNA binding through groove region with intrinsic binding constant 7.39 µM/bp and 6.86 µM/bp for 3BS and 2XP respectively. 2XP and 3BS showed strong DNA binding activity by the UV titration method with the computational drug modeling showed that both 2XP and 3BS failed to form any electrostatic linkages except via hydrophobic interaction through the minor groove region of the nucleic acid. The benzylvanillin alone (Bn1) has weak anticancer activity even after it was combined with the benzimidazole (2MP), but after addition of another benzylvanillin structure (2XP), stronger activity was observed. Also, the combination of benzylvanillin with benzenesulfonate (3BS) significantly improved the anticancer activity of Bn1. The present study provides a new insight of benzyl vanillin derivatives as potential anti-leukemic agent.

Benzimidazole derivative vs. different phases of TiO2-physico-chemical approach

1-Benzyl-2-phenyl-1H-benzo[d]imidazole (BPBI) has been synthesized by simple steps and characterized by spectral studies. Absorption and fluorescence spectral studies have been employed to investigate the interaction of BPBI with the anatase, hombikat, P25 and rutile phases of TiO2. The emission of the BPBI is efficiently quenched by anatase, hombikat and P25 TiO2 nanoparticles owing to charge injection from the excited singlet state of BPBI to the conduction band of the TiO2 nanoparticles. Surprisingly, rutile phase enhances the fluorescence which is likely due to lowering of LUMO and HOMO levels of the ligand on ducking of the benzimidazole moiety of the BPBI molecule into the void space of rutile TiO2. Electron injection from photoexcited BPBI to the TiO2 conduction band (S*→S(+)+e(-)(CB)) is likely to enhance the fluorescence.

5-Nitro-1,3-bis-(prop-2-yn-yl)-1H-1,3-benzimidazol-2(3H)-one

The title compound, C13H9N3O3, crystallizes with two identical but differently oriented mol-ecules in the asymmetric unit, the dihedral angle between the fused-ring systems of the two molecules being 64.39 (7)°. The two prop-2-ynyl chains are located on opposite sides of the mol-ecule and are nearly perpendicular to the fused ring plane, as indicated by the C-N-C-C torsion angles in the range 106.0 (3)-113.4 (3)°. In the crystal, the two mol-ecules are linked through C-H⋯O hydrogen bonds into dimers, which are subsequently linked by further C-H⋯O inter-actions, building a three-dimensional network.

Ethyl 2-oxo-3-(3-phthalimidoprop-yl)-2,3-dihydro-1H-1,3-benzimidazole-1-carboxyl-ate

In the title compound, C21H19N3O5, the phthalimide and benzamidazole ring systems are linked by a propyl chain. The benzamidazole unit also carries an eth-oxy-carbonyl substit-uent. The phthalimido and benzimidazole ring systems are essentially planar, the maximum deviations from their mean planes being 0.008 (2) and 0.020 (2) Å, respectively. The two ring systems are almost orthogonal to one another, making a dihedral angle of 82.37 (8)°. In the crystal, C-H⋯O hydrogen bonds and C-H⋯π contacts stack the mol-ecules along the b axis.

Zirconyl (IV) Nitrate as Efficient and Reusable Solid Lewis Acid Catalyst for the Synthesis of Benzimidazole Derivatives

The present paper introduces a simple and efficient method for the synthesis of substituted benzimidazoles by heterocyclization of differento-phenylenediamines and substituted aromatic carboxylic acid/aldehyde in the presence of zirconyl nitrate as catalyst in ethanol under reflux, which produced excellent yield of corresponding benzimidazoles in a short reaction time with reusability of catalyst.

1-(Prop-2-yn-yl)-1H-benzimidazol-2(3H)-one

The benzimidazolone part of the title mol­ecule, C₁₀H₈N₂O, is almost planar [r.m.s. deviation = 0.014 (1) Å] and the NCH₂C CH group forms a dihedral angle of 67.95 (6)° with its best plane. In the crystal, mol­ecules form inversion dimers via pairs of N—H⋯O hydrogen bonds. C—H⋯O inter­actions connect the dimers, forming a two-dimensional polymeric network parallel to (100).

Synthesis and Crystal Structure of 1-(4-Nitrobenzyl)-3-allyl-1H-benzo[d]imidazol-2(3H)-one

A functionalized benzimidazole, 1-(4-nitrobenzyl)-3-allyl-1H-benzo[d]imidazol-2(3H)-one, has been synthesized, and the crystal structure was determined and analyzed. This compound crystallizes in the monoclinic, space group P21/n (number 14)cwith cell parameters,a=7.12148(8) Å,b=16.12035(17) Å,c=13.04169(17) Å,β=93.3043(11),V=1494.71(3) Å3, andDcalc= 1.375 g/mm3. The solid state geometry is stabilized by intermolecularπ–πinteractions along with the van der Waals interactions which contribute to the stability of the crystal packing. Computational calculations have been used to properly understand the main intermolecular interactions present in the crystal.

1-Allyl-1H-1,3-benzimidazol-2(3H)-one

The fused five- and six-membered rings in the title compound, C(10)H(10)N(2)O, are approximately coplanar, with an r.m.s. deviation of 0.008 Å. The mean plane of the allyl group is roughly perpendicular to the mean plane of the 1,3-benzimidazol-2(3H)-one system, making a dihedral angle of 86.1 (2)°. In the crystal, each mol-ecule is linked to its symmetry equivalent partner by a pair of N-H⋯O and C-H⋯O hydrogen bonds.

Microwave-assisted synthesis of sec/tert-butyl 2-arylbenzimidazoles and their unexpected antiproliferative activity towards ER negative breast cancer cells

A new series of N-sec/tert-butyl 2-arylbenzimidazole derivatives was synthesised in 85-96% yields within 2-3.5 min by condensing ethyl 3-amino-4-butylamino benzoate with various substituted metabisulfite adducts of benzaldehyde under focused microwave irradiation. The benzimidazole analogues were characterised using (1)H NMR, (13)C NMR, high resolution MS and melting points. Evaluation of antiproliferative activity of the benzimidazole analogues against MCF-7 and MDA-MB-231 revealed several compounds with unexpected selective inhibitions of MDA-MB-231 in micromolar range. All analogues were found inactive towards MCF-7. The most potent inhibition against MDA-MB-231 human breast cancer cell line came from the unsubstituted 2-phenylbenzimidazole 10a.