Benzimidazole Groups Research Articles

Synthesis and Characterization of Poly(ether ether ketone-co-benzimidazole)s Based on 2-(2'-Hydroxyphenyl) benzimidazole

A series of novel poly(ether ether ketone)s containing benzimidazole groups with precise structures in high yields were synthesized from various stoichiometric ratio mixtures of m-dihydroxybenzene, 2-(2'- hydroxyphenyl)benzimidazole and 4,4′-difluorodiphenylmethanone via a C–N/C–O coupling reaction process using sulfolane as a solvent. The reaction was carried out at 210°C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FTIR, 1H NMR spectroscopy, elemental analysis, and the results were largely consistent with the proposed structure. XRD studies indicated that the resulted polymers are non-crystalline. The polymers have good solubilities in common organic solvents. The polymers showed high glass transition temperatures (Tg = 125–237°C) and high thermal stability (Td5% = 497–539°C in nitrogen, 466–548°C in air). At the same time, as the benzimidazole unit content in the copolymer increased, the thermal properties of the prepared polymers improved. Moreover, the resulted polymers showed good fluorescence properties and the fluorescence emission peak was 465 nm.

Phytotherapeutics: As anticipating substitutes to synthetic drugs in combating antinematicidal-resistant gastrointestinal nematodes of small ruminants

The plant kingdom embraces a plethora of various phytomedicines which have been exploited for thousands of years by conventional pastoralists, herbalists and healers as a part of ethno-veterinary medicine against livestock nematodiasis. The role of medicinal plants has been diminished after the marketing of synthetic thiabendazole (first generation of benzimidazole group) in 1961. Virtually, the magnitude of herbal medicines has been substantiated again in recent decades due to the rapid emergence of antinematicidal resistance among the parasitic nematode populations as a result of discriminate use of the synthetic chemotherapeutics worldwide. Furthermore, other promoted alternatives viz. biological control, immunization, grazing management, nutritional supplements and genetic approaches have not been commercialized yet due to some practical bottlenecks. In this article, the significance of medicinal botanicals and the performed studies in the field of phytotherapy toward antinematicidal-resistant alimentary tract nematodes parasitized ovine and caprine have been reviewed elaborately

Proton-Rocking-Chair-Type Redox Capacitors Based on Indium Tin Oxide Electrodes with Multilayer Films Containing Ru Complexes.

A rechargeable proton-rocking-chair-type redox capacitor was fabricated using scalable layer-by-layer-(LbL)-assembled films composed of two dinuclear Ru complexes that exhibit proton-coupled electron-transfer (PCET) reactions with different Ru(II/III) redox potentials (RuNH-OH and RuCH-OH). RuNH-OH and RuCH-OH contain different coordination environments that involve two phosphonate linker ligands at both ends and bridging 2,6,2',6'-tetrakis(benzimidazol-2-yl)-4,4'-bipyridine or 1,3,1',3'-tetrakis(benzimidazol-2-yl)-5,5'-biphenyl ligands, respectively. The molecular units were assembled onto indium tin oxide (ITO) electrodes by complexation between the phosphonate groups and zirconium(IV) ions. The LbL growing process of these multilayer films was monitored by electrochemical or UV-vis spectroscopic measurements. The thus obtained LbL films on the ITO electrodes showed PCET reactions at different potentials, depending on the bridging ligands. The introduction of cyclometalated Ru-C bonds in the bridging ligand of RuCH-OH led to the stabilization of the ruthenium(III) oxidation state, and therefore, RuCH-OH exhibited lower p Ka values for the imino N-H protons in the bridging benzimidazole groups compared to those of the corresponding RuNH-OH complex. The proton movements that accompany the redox reaction in the Ru multilayer films on the ITO electrode were confirmed using a pH indicator probe. For the performance test of a proton-rocking-chair-type redox capacitor, a two-electrode system composed of RuNH-OH and RuCH-OH multilayer films on ITO electrodes was examined in an aqueous solution of NaClO4. Under galvanostatic conditions, stable, reversible, and repeatable charging/discharging processes occurred. The capacitance increased with an increasing number of LbL layers. For comparison, a similar redox capacitor composed of two RuNMe-OH and RuCMe-OH analogues, in which all four imino N-H protons on the benzimidazole moieties are protected by N-Me groups, was constructed and examined. In these complexes, the capacitance decreased by 77% compared to the PCET-type capacitor composed of a cell containing RuNH-OH and RuCH-OH; this result strongly suggests that the proton movement plays a more important role for the charge storage than the anion movement. In such LbL films composed of Ru complexes that exhibit PCET-type redox reactions, the capacitance is drastically improved with an increasing number of layers and using protons as charge carriers.

The introduction of asymmetric heterocyclic units into poly(p-phenylene terephthalamide) and its effect on microstructure, interactions and properties

The asymmetric 5(6)-amino-2-(4-aminobenzene)benzimidazole (PABZ) was introduced into the main chain of poly(p-phenylene terephthalamide) (PPTA) in order to modify the solubility and properties. Introduction of more than 40% PABZ into PPTA main chain can effectively improve solubility and intrinsic viscosity ([η]) of poly(p-phenylene-benzimidazole-terephthalamide)s (PBIAs) in DMAC/LiCl solvent. Two-dimensional wide angle X-ray diffraction results indicate introduction of asymmetric poly(benzimidazole-terephthalamide) (PABI) segment disturbs the packing order along lateral direction, especially π–π stacking order, and when the content of PABI segment exceeds 50%, crystalline phase in PBIAs fibers is disappeared and crystalline domain orientation gradually decreases with increasing PABI segment content. However, high degree of order along fiber axis is retained due to the relative high rigidity and linearity of PABI segment. Fourier transform infrared results indicate the introduction of PABI segment strengthens hydrogen bonding interactions due to the presence of benzimidazole groups. The combined effects between chain order and hydrogen bonding interactions result in the highest tensile strength in PBIA-30 fiber as the content of PABI segment is 30%. Moreover, strong hydrogen bonding interactions are also favorable for enhancing interfacial shear strength (IFSS) and compressive strength. Meanwhile, homo-poly(benzimidazole-terephthalamide) fiber shows an IFSS 30.6% and compressive strength 33.3% higher than Kevlar 29 fiber.

Hydrogen-Bonded Organic⁻Inorganic Hybrid Based on Hexachloroplatinate and Nitrogen Heterocyclic Cations: Their Synthesis, Characterization, Crystal Structures, and Antitumor Activities In Vitro.

Three new crystal structures containing [PtCl6]2−, pyridinium and benzimidazole groups have been prepared: [PtCl6]·(H-bzm)2·2(H2O) (1), [PtCl6]·(H-bipy)2·2(H2O) (2), [PtCl6]·(H-dimethyl-bipy)2·2(H2O) (3) [H-bzm: benzimidazole cation, H-bipy: 2,2′-bipyridine cation, H-dimethyl-bipy: 4,4′-bimethyl-2,2′-bipyridine cation]. All compounds have been fully characterized by elemental analyses, single-crystal X-ray analyses, IR spectra, TG analyses, and fluorescence studies. Single-crystal X-ray diffraction analysis suggests that the primary synthon contains +N–H···Cl−, including ionic bonding and hydrogen bonding interactions. The dimensions are enhanced further by secondary O–H ∙∙Cl and N–H ∙∙O hydrogen bonding interactions between donor and acceptor atoms located at the periphery of these synthons. Moreover, coulombic attractions between the ions play an important role in reinforcing the structures of these complexes. In addition, antitumor activity against human lung adenocarcinoma cell line (A549) and human nasopharyngeal carcinoma cell line (CNE-2) was performed. These complexes all showed inhibition to the two cell lines, while complex 3 exhibited higher efficiency than complexes 1–2.

Carboxylate-Containing Two-Photon Probe for the Simultaneous Detection of Extra- and Intracellular pH Values in Colon Cancer Tissue.

Acidified extracellular pH (pHe) is directly related to various disorders such as tumor invasion and the resistance to drugs. In this study, we developed two-photon-excitable emission ratiometric probes (XBH1-3) for the in situ measurement of pHe. These probes, based on benzimidazole and polar solubilizing groups, exhibited a strong two-photon-induced fluorescence and sensitive blue-to-green emission color changes with p Ka values of 5.1-5.7. XBH1, containing a carboxylic acid, stained the extracellular region in neutral media; it entered the cell under acidic media, thereby allowing a precise measurement of the extra- and intra-cellular pH values in the acidified tissue. XBH2, containing the sulfonate peripheral unit, facilitated the monitoring of the pHe value only. Ratiometric two-photon microscopy imaging revealed that XBH1 can directly monitor the pH values both inside and outside the cells in colon cancer tissue; there is also the morphological aspect. This could be useful for cancer analyses and drug development.

Arylether-type polybenzimidazoles bearing benzimidazolyl pendants for high-temperature proton exchange membrane fuel cells

Phosphoric acid-doped polybenzimidazole membranes offer great potential for high-temperature proton exchange membrane applications due to their high proton conductivity at high-temperature and low-humidity conditions. However, it remains a major challenge in fabricating high-performance membranes with both high proton conductivity and good mechanical strength. Here, a series of polybenzimidazoles with increased imidazole groups are obtained by incorporating some benzimidazole groups onto an arylether-type polybenzimidazole backbone via a simple and efficient N-substituted reaction without catalyst. This arylether-type polybenzimidazole is verified to exhibit good solubility under extremely high molecular weight, and it provides the possibility for fabricating the high mechanical strength membranes at high phosphoric acid doping levels. It is of interest to find that the introduction of additional bulky benzimidazole moieties even enhance the mechanical strength of the membranes, and at the same time, significantly improve their acid doping levels, acid doping rate and proton conductivity. Importantly, the acid-doped grafted membranes show superior dimensional-mechanical stability even at high acid loading. With an acid doping level of 22.1, the grafted membrane displays a high conductivity of 212 mS cm−1 at 200 °C without humidification. A H2/O2 fuel cell based on this membrane has a peak power density of 443 mW cm−2 at 160 °C.

A series of new bipolar CBP derivatives with introduction of a electron-deficient moiety for efficient green organic light-emitting diodes

Abstract By introducing pyridine, benzimidazole and triazine groups, three novel CBP derivatives host materials, 9,9'-(2-(pyridin-3-yl)-[1,1′-biphenyl]-4,4′-diyl)bis(9H-carbazole) (CBPPY), 9,9'-(4''-(1- phenyl-1H-benzo[d]imidazol-2-yl)-[1,1':2′,1″-terphenyl]-4,4′-diyl)bis(9H-carbazole) (CBPBM) and 9,9'-(3''-(4,6-diphenyl-1,3,5-triazin-2-yl)-[1,1':2′,1″-terphenyl]-4,4′-diyl)Bis (9H-carbazole) (CBPTZ) were designed and synthesized. These three compounds exhibited high thermal stabilities, appropriate HOMO-LUMO energy levels and improved electroluminescent (EL) performance compared with CBP compound in Ir(ppy)3 doped green organic light emitting diodes (OLED). In addition, devices based on CBPPY, CBPBM and CBPTZ showed lower driving voltages of 3.0, 2.6 and 2.5 V, and all devices achieved higher EL efficiencies. Especially, the CBPBM-based device reached the optimal external quantum efficiencies (EQE) of 18.9% with the maximum power efficiency (PE) of 56.7 l m/W, which suggested that CBPPY, CBPBM and CBPTZ were promising bipolar host materials for green OLEDs.

Layer‐by‐layer Proton Donor and Acceptor Membrane for an Efficient Proton Transfer System in a Polymer Electrolyte Membrane Fuel Cell

AbstractThe high performance proton transfer in polymer electrolyte membranes (PEMs) is known to be achieved through cooperating of proton donors and acceptors. In order to obtain the effective and efficient proton transfer, the present work proposes a membrane with proton donors and proton acceptors in layer‐by‐layer (LbL) structure. By applying sulfonated poly (ether ether ketone) (SPEEK) as the substrate membrane and soaking alternatively with the proton donor polymer, i.e. poly(acrylic acid) (PAA), and the proton acceptor heterocycles, i.e. benzimidazoles (BI), the LbL SPEEK/BI/PAA membranes can be achieved. The systematic variation based on the branching benzimidazole groups suggest that the LbL SPEEK/BI/PAA membrane obtained shows an increase in proton conductivity compared to the neat SPEEK, especially in the case of the membrane with trifunctional benzimidazole (B4) is as high as 1–2.5 orders of magnitude over the temperature range of 30–170 °C. The present work points out the simple surface modification of the proton conductive membrane by layer‐by‐layer approach as a practical and simple way to enhance the performance of polymer electrolyte membrane.

Effect of anthelmintics upon host organism

To be estimated the effects of anthelmintics to the host, 21 female sheep of various age, breed and weight, which were naturally infected with gastrointestinal nematodes, were used. These animals were divided into three groups and given per os: in the 1st group, which was composed of 7 sheep, Morantel citrate (tetrahydropyrimidine group) approx. 465 mg/b.w., in the 2nd, which was composed of 8 sheep, Albendazole (benzimidazole group) approx. 300 mg/b.w. and in the 3rd, which was composed of 6 sheep, tap water only and this group was used as control. From these animals, blood samples intrajagularly were taken, at the same day, once a week for 9 continuous weeks. The first blood sample was taken 4 weeks before the anthelmintic therapy and the last one 5 weeks after therapy. There were no significance diferences (p> 0,005) in pre- and posttherapy measurements, regarding the PCV,s in all groups. In the control and morantel citrate groups, the leucocyte volume remained static, while contrarily, in the albendazole group a significance difference (p< 0,005) were observed. Because, the albendazole inhibits the construction of intestine cell microtubules of parasites, it can be concluded that, this activity, effects the host cells, and thus, this reduction of leucocytes was observed.

Phosphoric Acid Doped Crosslinked Polybenzimidazole/Modified Graphene Oxide Composite Membranes for High Temperature Proton Exchange Membrane Applications

A radiation grafting graphene oxide reinforced polybenzimidazole (PBI-RGO) was fabricated and then crosslinked with a self-made crosslinker containing benzimidazole groups by a facile method to obtain crosslinked PBI/RGO (cPBI/RGO) membrane, which was further doped with phosphoric acid (PA) for high temperature proton exchange membrane (HT-PEM) applications. The introduction of benzimidazole groups in the crosslinker results in an increase in PA uptake from 222% to 303% and a reduction of tensile strength of the membrane. The crosslinking structure can effectively improve the tensile strength compared with uncrosslinked membrane at the same PA uptake. The crosslinked membrane shows higher remaining weight after immersion in Fenton's solution for 6 days and PA for 8 days than uncrosslinked membrane, indicating that it has better oxidative and chemical stability. The introduction of RGO and the crosslinking structure can also improve the proton conductivity of membrane. The proton conductivity of PA-doped cPBI/RGO membrane is 58.6 mS·cm−1 at 170°C without humidity, which is increased by 2.6 times compared with that of PA-doped PBI membrane. The crosslinking structure allows the membrane to have better stability and higher proton conductivity, thus making it suitable for HT-PEM applications.

A highly selective TPE-based AIE fluorescent probe is developed for the detection of Ag.

The detection of Ag+ in the environment is very important to determine the level of pollution from silver complexes, which have caused various human health problems. Herein, an aggregation-induced emission (AIE) chromophore (tetraphenylethane, TPE) attached to a benzimidazole group (tetra-benzimidazole, TBI–TPE) is synthesized and utilized to detect Ag+ in the environment. The strong chelating effect between the benzimidazole group and Ag+ leads to the formation of aggregates, and strong yellow fluorescence signals were observed after adding Ag+ into a TBI–TPE solution. The stoichiometry of the complex of TBI–TPE and Ag+ was established to be 1 : 2 using photochemical and mass spectra measurements. The detection limit of the Ag+ assay is 90 nM with a linear range from 100 nM to 6 μM. This study provides a facile method to determine Ag+ in real environmental samples with satisfactory results.

A novel thiazolidinediones ATZD2 rescues memory deficits in a rat model of type 2 diabetes through antioxidant and antiinflammation

Type 2 diabetes (T2DM) has been associated with learning and memory impairment; however, drugs for diabetes could not prevent the development of cognitive decline in T2DM patients. In the present study, compounds derived from thiazolidinediones (TZD), a PPAR-γ agonist, were synthesized by conjuncting the alkyl-substituted benzimidazole group to TZD group (ATZDs). Based on the in vitro evaluation, the neuroprotection of ATZD2 was further investigated using a streptozotocin-induced T2DM rat model. Pharmacokinetic study showed that ATZD2 could pass the blood-brain barrier (BBB) while the rosiglitazone (RSG, the precursor compound of ATZD2) not. Administration of ATZD2 significantly promoted the survival rate and attenuated fasting blood glucose (FBG) levels as compared to RSG treatment in T2DM rats. Furthermore, ATZD2 treatment ameliorated the impairment of learning and memory by Morris water maze test. The beneficial effects of ATZD2 were associated with the down-regulation of hypoxia induced factor-1α, aldose reductase, and Bax expression which are related to T2DM pathology. ATZD2 treatment also attenuated the expression of inflammatory cytokines and restored the balance of redox in the diabetic hippocampus. These effects were more potent as compared with that of RSG at the same dose. The data indicate that ATZD2 may be a potent agent for the treatment of cognitive dysfunction in T2DM.

Flubendazole induces mitotic catastrophe and apoptosis in melanoma cells

Flubendazole (FLU) is a widely used anthelmintic drug belonging to benzimidazole group. Recently, several studies have been published demonstrating its potential to inhibit growth of various tumor cells including those derived from colorectal cancer, breast cancer or leukemia via several mechanisms. In the present study we have investigated cytotoxic effects of FLU on malignant melanoma using A-375, BOWES and RPMI-7951 cell lines representing diverse melanoma molecular types. In all three cell lines, FLU inhibited cell growth and proliferation and disrupted microtubule structure and function which was accompanied by dramatic changes in cellular morphology. In addition, FLU-treated cells accumulated at the G2/M phase of cell cycle and displayed the features of mitotic catastrophe characterized by formation of giant cells with multiple nuclei, abnormal spindles and subsequent apoptotic demise. Although this endpoint was observed in all treated melanoma lines, our analyses showed different activated biochemical signaling in particular cells, thus suggesting a promising treatment potential of FLU in malignant melanoma warranting its further testing.

Functional Chemical Groups that May Likely Become a Source for the Synthesis of Novel Central Nervous System (CNS) Acting Drugs.

Central Nervous System (CNS) disorders are on increase perhaps due to genetic, enviromental, social and dietetic factors. Unfortunately, a large number of CNS drugs have adverse effects such as addiction, tolerance, psychological and physical dependence. In view of this, literature search was carried out with a view to identify functional chemical groups that may serve as lead molecules for synthesis of compounds that may have CNS activity. The search revealed that heterocycles that have heteroatoms such as nitrogen (N), sulphur (S) and oxygen (O) form the largest class of organic compounds. They replace carbon in a benzene ring to form pyridine. Compounds with furan, thiophene, pyrrole, pyridine, azole, imidazole, indole, purine, pyrimidine, esters, carboxylic acid, aldehyde, pyrylium, pyrone, pyrodine, barbituric acid, barbiturate, quinoline, quinolone, isoquinolone, coumarin, alkylpyridine, picoline, piperidine, diazine, carboxamide, flavonoid glycoside, oxindole, aminophenol, benzimidazole, benzoxazole, benzothiazole, and chromone chemical groups among others may have CNS effects ranging from depression passing through euphoria to convulsion. Examples of the compounds with the functional groups include but not limited to coal tar, pyridostigmine, pralidoxime, quinine, mefloquine, pyrilamine, pyronaridine, ciprofloxacin and piroxicam. A number of them can undergo keto-enol tautomerism. Chiral amines may be used for derivation of chiral carboxylic acids which are components of tautomers. Some tautomers may cause parkinsonism and Stevens Johnson syndrome.

An assessment of benzimidazole resistance against caprine nematodes in Central India.

Current status of resistance to benzimidazole (BZ) group of anthelmintic drugs against caprine nematodes in Central India at Amanala goat farm, Jabalpur, Madhya Pradesh (M. P.), was systematically investigated using faecal egg count reduction (FECR) test and egg hatch test (EHT). Besides, allele-specific PCR (AS-PCR) was deployed to ascertain the susceptible genotype (alleles) especially of the Haemonchus contortus. Randomly selected 30 goats, irrespective of age and sex, were divided into three groups of 10 each, to serve as treated and untreated controls. It was ensured that the animals were not administered with an anthelmintic drug for the past 3months prior to undertaking the study, and faecal egg counts were estimated. FECR test evidenced fenbendazole resistance by partial elimination (24.90%) copro-egg counts in the treated group of animals vis-à-vis controls with a lower confidence interval of -26%. Further, EHT revealed ED-50 value of 0.335μg of thiabendazole/ml, confirming benzimidazole resistance in the animals of that farm. AS-PCR showed that 62% of H. contortus larvae were homozygous resistant (rr), 24% heterozygous (rS) and 14% homozygous susceptible (SS). The genotypic frequencies of three genotypes (rr, rS and SS) were significantly (P<0.01) different. The prevalence of benzimidazole resistance allele (r) was also significantly (P<0.01) higher (74%) as compared to susceptible allele (S) (26%). The resistance to benzimidazole has been discussed while emphasizing improved managemental practices designed to reduce exposure of the goat population to parasites, minimize frequency of anthelmintic use at optimum dose and rotational use of different chemical groups of medicines with different mode of action, so as to overcome and combat the upcoming problem in the field.

Modulatory Role of Nurr1 Activation and Thrombin Inhibition in the Neuroprotective Effects of Dabigatran Etexilate in Rotenone-Induced Parkinson's Disease in Rats.

Recently, it has been shown that both decreased nuclear receptor-related 1 (Nurr1) expression and thrombin accumulation are involved in the degeneration of dopaminergic neurons in Parkinson's disease (PD). The new anticoagulant dabigatran etexilate (DE) is a direct thrombin inhibitor that owns benzimidazole group, which has been proposed to activate Nurr1. In the present study, we examined the neuroprotective effects of DE in rotenone model of PD. Rotenone was injected subcutaneously at a dose of 1.5mg/kg every other day for 21days. An oral regimen of DE (15mg/kg) was started after the 5th rotenone injection following the manifestations of PD. Treatment of PD rats with DE mitigated rotenone-induced neuronal degeneration and restored striatal dopamine level with motor recovery. As well, DE enhanced Nurr1 expression in substantia nigra along with increasing transcriptional activation of Nurr1-controlled genes namely tyrosine hydroxylase, vascular monoamine transporter, glial cell line-derived neurotrophic factor, and its receptor gene c-Ret, which are critical for development and maintenance of dopaminergic neurons. DE also suppressed thrombin accumulation in substantia nigra. Both effects probably contributed to repressing neurotoxic proinflammatory cytokines, which was manifested by decreased level of nuclear factor kappa beta and tumor necrosis factor alpha. In conclusion, the present results suggest that DE could possess significant neuroprotective and regenerative effects in a rotenone-induced PD animal model as consequence of Nurr1 activation and thrombin inhibition.

Gastrointestinal nematode populations with multiple anthelmintic resistance in sheep farms from the hot humid tropics of Mexico.

This study evaluated the status of anthelmintic resistance against the three available classes of commercial drugs in seven sheep farms in the hot humid tropics of Mexico. Drug classes included benzimidazole (BZ), ivermectin (IVM) and levamisole (LV). Respective faecal egg count reduction tests (FECRT) were performed in each farm. Faecal samples were obtained from the rectum of >100 sheep in each farm. Adult sheep shedding >150 eggs per gram of faeces (EPG) were included. In each farm, animals were allotted to one of four groups with similar mean EPG: Control Group (untreated), BZ group (albendazole sulfoxide 5mg/kg LW), IVM group (ivermectin, 0.2mg/kg LW) and LEV group (levamisole 7.5mg/kg LW). Drugs were administered subcutaneously. A second faecal sampling was performed on the same animals of each farm 14days post-treatment. The GIN genera obtained from faecal cultures were identified for each group in different farms. Percentage faecal egg count reduction (%R) and 95% confidence intervals were estimated using the RESO© software. A questionnaire was applied to farm owners to describe anthelmintic management practices. All sheep farms had GIN populations with multiple resistance to the three anthelmintic classes tested. The %R ranged from 0 to 48% for BZ, 29 to 82% for IVM and 1 to 88% for LEV. Haemonchus spp. and Trichostongylus spp. were found in all treated groups of the study farms. Resistant Oesophagostomum spp. larvae (BZ or IVM) were found in respective farms. Treatment practices in study farms included frequent mass treatment every two months with extra treatments applied individually in the presence of clinical signs. Drug dosage used visual estimation of body weight rather than the exact weight of each animal. Quarantine anthelmintic treatment of incoming stock was used but efficacy was not confirmed.

Structure of the mercury(II) mixed-halide (Br/Cl) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzo[d]imidazole).

The mercury(II) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benz-imidazole), namely catena-poly[[dihalogenido-mercury(II)]-μ-2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzimidazole)-κ2N3:N3'], [HgBr1.52Cl0.48(C34H42N4)], 2, has a polymeric structure bridging via the N atoms from the benzimidazole moieties of the ligand. The compound crystallizes in the ortho-rhom-bic space group Pca21 and is a racemic twin [BASF = 0.402 (9)]. The geometry around the HgII atom is distorted tetra-hedral, with the HgII atom coordinated to two N atoms, one Br atom, and a fourth coordination site is occupied by a mixed halide (Br/Cl). For the two ligands in the asymmetric unit, there is disorder with one of the two tert-butyl groups and benzimidazole moieties showing twofold disorder, with occupancy factors of 0.57 (2):0.43 (2) for the tert-butyl group and 0.73 (3):0.27 (3) for the benzimidazole group. In addition, there is threefold disorder for two of the four n-pentyl groups, with occupancy factors of 0.669 (4):0.177 (4):0.154 (4) and 0.662 (4):0.224 (4):0.154 (4), respectively. The mol-ecules form a one-dimensional helical polymer propagating in the b-axis direction. The helices are held together by intra-strand C-H⋯Br and C-H⋯Cl inter-actions. Each strand is further linked by inter-strand C-H⋯Br and C-H⋯Cl inter-actions. In addition, there are weak C-H⋯N inter-strand inter-actions which further stabilize the structural arrangement.

Anthelmintic Flubendazole and Its Potential Use in Anticancer Therapy.

Flubendazole is a widely used anthelmintic drug belonging to benzimidazole group. The molecular mechanism of action of flubendazole is based on its specific binding to tubulin, which results in disruption of microtubule structure and function, and in the interference with the microtubule-mediated transport of secretory vesicles in absorptive tissues of helminths. The microtubule-disrupting properties of benzimidazole derivatives raised recently interest in these compounds as possible anti-cancer agents. In this minireview flubendazole effects towards selected human malignant cells including myeloma, leukemia, neuroblastoma, breast cancer, colorectal cancer and melanoma are discussed along with basic data on its pharmacokinetics, metabolism and toxicity.