Acidic hydrolysis of N-Ethoxybenzylimidazoles (NEBIs): potential applications as pH-sensitive linkers for drug delivery

This paper describes the development of a new class of N-linked imidazoles as potential pH-sensitive, cleavable linkers for use in cancer drug delivery systems. Kinetic analysis of eight derivatives of N-ethoxybenzylimidazoles (NEBIs) showed that their rates of hydrolysis are accelerated in mild aqueous acidic solutions compared to in solutions at normal, physiological pH. Incorporation of electron donating or electron withdrawing substituents on the phenyl ring of the NEBI resulted in the ability to tune the rates of hydrolysis under mild acidic conditions with half-lives ranging from minutes to months. A derivative of NEBI carrying doxorubicin, a widely used anticancer agent, also showed an increased rate of hydrolysis under mild acid compared to that at normal physiological pH. The doxorubicin analogue resulting from hydrolysis from the NEBI exhibited good cytotoxic activity when exposed to human ovarian cancer cells. These results demonstrate a potentially useful, general strategy for conjugating a wide range of drugs to imidazole-containing delivery vessels via NEBI functionalities for controlled release of therapeutics for drug delivery applications.

Solid-phase microextraction of benzimidazole fungicides in environmental liquid samples and HPLC–fluorescence determination

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection was optimized for extraction and determination of four benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and fuberidazole) in water. We studied extraction and desorption conditions, for example fiber type, extraction time, ionic strength, extraction temperature, and desorption time to achieve the maximum efficiency in the extraction. Results indicate that SPME using a Carboxen-polydimethylsiloxane 75 microm (CAR-PDMS) fiber is suitable for extraction of these types of compound. Final analysis of benzimidazole fungicides was performed by HPLC with fluorescence detection. Recoveries ranged from 80.6 to 119.6 with RSDs below 9% and limits of detection between 0.03 and 1.30 ng mL-1 for the different analytes. The optimized procedure was applied successfully to the determination of benzimidazole fungicides mixtures in environmental water samples (sea, sewage, and ground water).

Topoisomerase I-mediated DNA cleavage induced by the minor groove-directed binding of bibenzimidazoles to a distal site

Many agents (e.g. camptothecins, indolocarbazoles, indenoisoquinolines, and dibenzonaphthyridines) stimulate topoisomerase I (TOP1)-mediated DNA cleavage (a behavior termed topoisomerase I poisoning) by interacting with both the DNA and the enzyme at the site of cleavage (typically by intercalation between the -1 and +1 base-pairs). The bibenzimidazoles, which include Hoechst 33258 and 33342, are a family of DNA minor groove-directed agents that also stimulate topoisomerase I-mediated DNA cleavage. However, the molecular mechanism by which these ligands poison TOP1 is poorly understood. Toward this goal, we have used a combination of mutational, footprinting, and DNA binding affinity analyses to define the DNA binding site for Hoechst 33258 and a related derivative that results in optimal induction of TOP1-mediated DNA cleavage. We show that this DNA binding site is located downstream from the site of DNA cleavage, encompassing the base-pairs from position +4 to +8. The distal nature of this binding site relative to the site of DNA cleavage suggests that minor groove-directed agents like the bibenzimidazoles poison TOP1 via a mechanism distinct from compounds like the camptothecins, which interact at the site of cleavage.

Common pharmacophores for uncharged human ether-a-go-go-related gene (hERG) blockers

In silico approaches are widely used to predict human ether-a-go-go-related gene (hERG) channel blockade. Published pharmacophore models of hERG blockers typically contain a basic nitrogen center flanked by aromatic or hydrophobic groups. However, hERG blockade has been observed in series lacking the basic nitrogen. By utilizing screening data for 194 potent uncharged hERG actives, we propose a pharmacophore for neutral hERG blockers, and provide guidance on eliminating hERG liability in an uncharged hERG active chemical series.

In Silico Binding Free Energy Predictability by Using the Linear Interaction Energy (LIE) Method: Bromobenzimidazole CK2 Inhibitors as a Case Study

Protein kinase CK2 is essential for cell viability, and its control regards a broad series of cellular events such as gene expression, RNA, and protein synthesis. Evidence of its involvement in tumor development and viral replication indicates CK2 as a potential target of antineoplastic and antiviral drugs. In this study the Linear Interaction Energy (LIE) Method with the Surface Generalized Born (SGB) continuum solvation model was used to study several bromobenzimidazole CK2 inhibitors. This methodology, developed by Aqvist, finds a plausible compromise between accuracy and computational speed in evaluating binding free energy (DeltaGbind) values. In this study, two different free binding energy models, named "CK2scoreA" and "CK2scoreB", were developed using 22 inhibitors as the training set in a stepwise approach useful to appropriately select both the tautomeric form and the starting binding position of each inhibitor. Both models are statistically acceptable. Indeed, the better one is characterized by a correlation coefficient (r2) of 0.81, and the predictive accuracy was 0.65 kcal/mol. The corresponding validation, using an external test set of 16 analogs, showed a correlation coefficient (q2) of 0.68 and a prediction root-mean-square error of 0.78 kcal/mol. In this case, the LIE approach has been proved to be an efficient methodology to rationalize the difference of activity, the key interactions, and the different possible binding modes of this specific class of potent CK2 inhibitors.

Hydrogen-bonded chains of rings in methyl 4-[(5-methyl-1H-pyrazol-3-yl)amino]-3-nitrobenzoate and hydrogen-bonded sheets in methyl 1-(5-methyl-1H-pyrazol-3-yl)-1H-benzimidazole-5-carboxylate

Molecules of methyl 4-[(5-methyl-1H-pyrazol-3-yl)amino]-3-nitrobenzoate, C12H12N4O4, (I), exhibit a polarized (charge-separated) structure in the nitroaniline portion. The molecules are linked into chains of edge-fused R(2)2(16) and R(2)2(22) rings by a combination of N-H...O(carbonyl) and C-H...O(nitro) hydrogen bonds. Methyl 1-(5-methyl-1H-pyrazol-3-yl)-1H-benzimidazole-5-carboxylate, C13H12N4O2, (II), which is readily formed from (I) by reduction followed by ring formation, crystallizes with Z' = 2 in the space group P-1. Each of the two independent molecular types is linked into sheets of R(4)4(28) rings by a combination of N-H...N and C-H...O(carbonyl) hydrogen bonds.

Carbodiimide-based benzimidazole library method

Using carbodiimide reagents [1,3-diisopropylcarbodiimide or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC)], we have developed a mild, generalized, one-pot method that delivers N-2-arylaminobenzimidazole esters from commercially available aryl isothiocyanates and o-phenylenediamines. Following saponification and acidifying, the benzimidazole acids were isolated in overall yields ranging from 75 to 88% from the starting aryl isothiocyanates. Nine benzimidazole acids were converted into a library consisting of 180 benzimidazole amides following EDC coupling with commercially available amines. The National Institute of General Medical Science will dispense these benzimidazole amides to academia groups for pilot scale biomedical studies. Using these mild conditions and environmentally safe reagents, we demonstrated that these pharmaceutically ornate heterocycles can also be constructed on solid support.

The use of propidium iodide to assess excitotoxic neuronal death in primary mixed cortical cultures

Neurodegenerative disorders are subjects of intense scrutiny in biomedical research because of their often-debilitating effects. Currently, many laboratories are engaged in developing or testing drugs to prevent neuronal loss in a variety of these pathologies. A key to testing such drugs is the use of a fast, reliable, and easily reproducible model of neurodegeneration and neuroprotection. Our laboratory has previously used propidium iodide (PI) to assess the degree of neurodegeneration and neuroprotection under a variety of conditions. Ultimately, efforts are underway in the laboratory to prevent delayed neuronal loss following acute ischemic insults using drug therapies. It is now believed that a key mechanism of neurodegeneration following acute ischemia or anoxia is a result of excitotoxicity via N-methyl-D-aspartate receptors (NMDARs) and subsequent overproduction of nitric oxide via neuronal nitric oxide synthase (nNOS). Thus, for the purposes of this chapter, the insult used to induce cell death will be various concentrations of NMDA and the compound used to demonstrate neuroprotection will be the nonspecific NOS inhibitor No-nitro-L-arginine methyl ester (L-NAME). Assessment of neuronal death is accomplished by measuring changes in PI fluorescence using a fluorescent plate reader. This chapter will outline the necessary steps required to (1) produce primary mixed cortical cultures, (2) apply PT and NMDA to these cultures, (3) quantify the results obtained from these cultures, and (4) image these cultures in conjunction with Hoechst 33342 and immunocytochemistry using fluorescence microscopy.

Comparative Studies on Conventional and Microwave Assisted Synthesis of Benzimidazole and Their 2-Substituted Derivative with the Effect of Salt Form of Reactant

Benzimidazole and their derivative were reported to have wide biological activities and were synthesized by using different solvents and ring closing agents. The present work deals with the comparative synthesis of 2-alkyl and aryl substituted benzimidazole derivative in the presence of polyphosphoric acid through microwave and conventional methods and also studied the effect of salt form of reactant for completion of the reaction. The 2-substituted aryl and alkyl benzimidazole derivative were synthesized via microwave and was observed to be more beneficial, in respect of yield (increases up to 10 to 50%) and time (96 to 98% was reduced) than conventional method of synthesis. This study was concluded that the salt form of reactant (o-phenylenediamine dihydrochloride) gave reduced colour impurities, homogenous mixing and reduced time for completion of reaction.

1H-Benzimidazole derivatives as mammalian DNA topoisomerase I inhibitors

Benzimidazole is one of the most important heterocyclic groups manifesting various biological properties, such as antibacterial, antifungal, antimicrobial, antiprotozoal and antihelmintic activities. Several benzimidazole derivatives are also active as inhibitors of type I DNA topoisomerases. In this study, three 1H-benzimidazole derivatives with different electronic characteristics at position 5-, namely 5-chloro-4-(1H-benzimidazole-2-yl)phenol (Cpd I), 5-methyl-4-(1H-benzimidazole-2-yl)phenol (Cpd II) and 4-(1H-benzimidazole-2-yl)phenol (Cpd III), were synthesized and evaluated for their effects on mammalian type I DNA topoisomerase activity using quantitative in vitro plasmid supercoil relaxation assays. For the structure elucidation of the compounds, melting points, UV, IR, 1H NMR, 13C NMR, mass spectral data and elemental analyses were interpreted. Among the compounds, 5-methyl-4-(1H-benzimidazole-2-yl)phenol (Cpd II) manifested relatively potent topoisomerase I inhibition.

Benzimidazole Nitrogen-Directed, Regiocontrolled, Lithiation of Ferrocenyl- and Phenyl-N-n-butylbenzimidazoles

2-Ferrocenyl- and 2-phenyl-N-n-butylbenzimidazoles were synthesized to evaluate the influence of the benzimidazole functional group upon their directed lithiation. The regiochemistry of lithiation was studied, as well as the effect of stabilization of the lithiated species by diamine coordination using tetramethyl- ethylenediamine and (-)-sparteine. The lithiations were followed by reaction with a variety of electrophiles to give the disubstituted 2-ferrocenyl- and 2-phenyl-N-n-butylbenzimidazoles compounds. This study showed that despite a simple n-butyl function on the benzimidazole, directed lithiation was readily achieved with high regiocontrol on the ferrocenyl and phenyl groups. (-)-Sparteine failed to provide asymmetric induction in the ferrocene system, and its inefficiency is explained by intramolecular coordination of the lithiated species by the benzimidazole nitrogen, which is preferred over sparteine coordination.

Isolation of side population cells from ginbuna carp (Carassius auratus langsdorfii) kidney hematopoietic tissues

Side population (SP) cells, characterized by a specific Hoechst dye efflux pattern by flow cytometry were isolated from kidney hematopoietic tissues of ginbuna carp (Carassius auratus langsdorfii). The hematopoietic activity of SP cells was evaluated by the repopulation and multilineage potential using an in vivo transplant system of ginbuna carp (donor) and ginbuna-goldfish hybrids (recipient). In a flow cytometric (FCM) analysis, a small and distinct population of ginbuna SP cells displayed efficient effluxes of Hoechst 33342 was virtually identical to the efflux observed in mammalian SP cells. The frequency of the ginbuna SP cells was 0.17+/-0.08% in the kidney hematopoietic cells. Morphologically, SP cells were composed of small lymphocyte-like cells having a thin-layered cytoplasm and a round nucleus. These characteristics of ginbuna SP cells were very similar to those of mammalian SP cells. Since cyprinid fish have two hematopoietic sites, the head (anterior) and body (posterior, trunk) kidney, the distribution of SP cells were examined in head and body kidney. The proportion of SP cells were 0.33+/-0.15% in the body kidney, but near 0% in the head kidney. After the ginbuna SP cells were injected into ginbuna-goldfish hybrids, the major types of donor-derived cells (erythrocytes, neutrophils, basophils, monocytes, thrombocytes, T and B lymphocytes) were detected in the recipient blood over a long period (9-16 months post-transplantation). In ginbuna carp, SP cells reside in the body kidney and contain primitive populations of hematopoietic stem cells (HSCs).

Review of methodology for the determination of benzimidazole residues in biological matrices

Benzimidazoles are anthelmintic agents widely used in the treatment of parasitic infections in a range of species and as fungicidal agents in the control of spoilage of crops during storage and transport. In this paper, the more important benzimidazoles are introduced and their pharmacological effects and physiochemical properties discussed. The metabolism of these drugs is described relating to the occurrence and persistence of residues in biological matrices, providing information for selection of suitable matrices and target residues for testing. Methods for determination of benzimidazoles are reviewed for a range of biological matrices. The importance of selecting suitable extraction and clean-up procedures is discussed, along with the difficulties encountered in adapting single residue methods to multi-residue methods. The importance of suitable detection systems for determination of benzimidazoles, namely, screening, HPLC, GC and confirmatory methods is described in detail. The future for benzimidazole residue analysis is discussed, focusing on selection of appropriate residues for screening methods and protocols for confirmation of benzimidazole residues.

Zn-Proline Catalyzed Selective Synthesis of 1,2-Disubstituted Benzimidazoles in Water

Zn-proline (5 mol%) performs as a novel water-soluble and recyclable Lewis acid catalyst for the selective synthesis of 1,2-disubstituted benzimidazoles from wide range of substituted o-phenylenediamines and aldehydes in moderate to excellent isolated yields (42-92%) using water as solvent at ambient temperature.

Matrix-assisted laser desorption/ionization studies on transition metal complexes of benzimidazole thiosemicarbazones

The transition metal (M=Fe, Co, Ni, Cu, Zn, Cd and Hg) complexes of 2- acetylbenzimidazolethiosemicarbazone (L(1)) and 1-methyl 2-acetylbenzimidazole-thiosemicarbazone (L(2)) are analyzed by MALDI using HCCA, THP, MMNPD and DMN as the matrices. All the MALDI spectra are clean without any contribution from the complex ions resulted by multiple proton addition/removal. All the complexes, except Cu, irrespective of the matrix used, show 1:2 complex ions wherein two ligands (neutral or deprotonated) complex with the metal ion depending on the nature and stable oxidation state of the central metal ion viz., [M + 2L - 2H](+) ion for Fe and Co complexes (+3 oxidation state) and [M + 2L - H](+) ion for Ni, Zn, Cd and Hg (+2 oxidation state). The Cu complex show 1:1 complex ion corresponding to [2M + 2L - 2H](+) ions. When HCCA is used as a matrix, the complex ions due to ligand exchange by matrix are also found, and this process is relatively more if a neutral ligand is bound to the metal ion in the original complex ion. The type of complex ions found under MALDI experiments are similar to those found under ESI experiments. However, the complex ions due to reduction of Cu are found only in the MALDI analysis of Cu complexes.

Synthesis and evaluation of intercalating somatostatin receptor binding peptide conjugates for endoradiotherapy

PURPOSE

Intercalators, planar aromatic compounds, are able to interact with DNA by sandwiching themselves between the stacked bases at right angles to the long axis of the helix. Under certain circumstances, Auger-electron-emitting radionuclides can be extremely radiotoxic and produce extensive DNA damage. Auger electron-emitting radioisotopes, are known to be highly cytotoxic when localized in cell nuclei due to highly localized energy deposition by low energy Auger electrons. In addition binding to the DNA might increase the retention in the receptor expressing tissues.

METHODS

In order to exploit the cytotoxic potential of intercalator-Auger-emitter conjugates, bis-benzimidazole dyes, Hoechst 33258 and 33342, were linked to a somatostatin receptor affine carrier peptide. For this purpose a bis-benzimidazole intercalating moiety was prepared using variations on the literature methods. The intercalating moieties were coupled under normal SPPS conditions to the carrier peptide, Tyr3-octreotate. To attach the chelating agent (DOTA) to the intercalating moiety, a free amine derivative was prepared and coupled in solution to DOTA tris-t-butyl ester. The resulting chelator-intercalator conjugate was then coupled to a Tyr3-octreotate carrying resin using SPPS.

RESULTS

The peptide conjugates were obtained in good yields after HPLC chromatography. The cellular uptake of the novel conjugates was determined using fluorescence microscopy. All intercalator-peptide conjugates revealed somatostatin receptor binding affinities in the nanomolar range.

CONCLUSIONS

The novel chelator-intercalator derivatives of the somatostatin receptor binding Tyr3-octreotate introduce a new scope to the range of tracers for therapeutic purposes.

[Effect of benzimidazole and its derivatives on electrical activity of Helix albescens Rossm neurons and behavior of rats]

We studied concentration dependency and the mechanisms of the effect of bezimidazole and its new derivatives on electrical processes in Helix albescens Rossm. neurons. These compounds appeared to have neurotropic properties dependent on their chemical structure and the types of neurons. We determined the threshold, optimal and toxic concentration values of the tested substances. Benzimidazole and 2-trifluoromethylbenzimidazole at concentrations of 10(-3) and 10(-2) M elicit both excitatory and inhibitory postsynaptic potentials on soma membrane of some pacemaker and non-pacemaker neurons and even cause a strong depolarization. The membrane of pacemaker neurons (namely, neuron RPa2) was found to have at least two spatially separated trigger sites with different trigger mechanism of action potential. After single intraperitoneal injection (50 mg/kg) of the substance solution, the tested compounds based on the discovered effects were separated into two groups. The first group inhibits locomotion and psychoemotional state of rats, the second group elicits the opposite effect. We found that at 100 and 150 mg/kg all tested substances inhibit the animal's activity.

One-pot synthesis of 2-C-glycosylated benzimidazoles from the corresponding methanal dimethyl acetals

A series of 2-glycosyl-benzimidazoles with alpha-d-arabinopyranosyl, beta-d-galactopyranosyl, beta-d-glucopyranosyl, beta-d-mannopyranosyl, and beta-l-rhamnopyranosyl configurations were obtained in 52-73% yields from the corresponding C-glycosylmethanal dimethyl acetals and o-phenylenediamine under catalysis with hydrogen chloride or a strongly acidic cation-exchange resin. Intermediate benzimidazolines were spontaneously oxidized by air to produce the final products in the one-pot procedure. The prepared compounds did not show any inhibitory effect on the growth of 12 strains of five different species of pathogenic yeasts.

3D-ordered macroporous materials comprising DNA

Macroporous materials comprising DNA were fabricated with the colloidal crystal template. First, DNA and diazoresin (DR) molecules are fully filled into the voids of a colloidal crystal template. After thermal treatment and removal of the colloids, DNA porous materials with highly ordered structure were obtained. In the process of thermal treatment the cross-linking reaction takes place between DR and DNA, which plays an important role for sustaining the porous framework. The DNA porous materials will turn into a fluorescent DNA/dye composite after staining with Hoechst 33258 (Hoe), a characteristic fluorescent dye for DNA. This kind of composite DNA porous material may have potential applications in optical devices.

Benzofused Tricycles Based on 2-Quinoxalinol

This paper describes our recent efforts to synthesize novel compound scaffolds integrating 2-quinoxalinol with privileged structures of 1,3-dihydro-benzoimidazol-2-one, 1,3-dihydro-benzoimidazole-2-thione, 3-hydroxy-1H-quinoxalin-2-one, 2H-benzo[1,4]oxazin-3-ol, 2H-benzo[1,4]thiazin-3-ol, and 1,3,4,5-tetrahydro-benzo[1,4]diazepin-2-one, respectively. Eight novel benzofused tricycles and their substituent diversity points were developed. These include pyrazino[2,3-g]quinoxaline-2,8-diol (I), 3-hydroxy-6,8,9,10-tetrahydro-1,4,6,10-tetraaza-cyclohepta[b]naphthalen-7-one (II), 6-hydroxy-4H-1-oxa-4,5,8-triaza-anthracen-3-one (III), 6-hydroxy-4H-1-thia-4,5,8-triaza-anthracen-3-one (IV), 6-hydroxy-1,1-dioxo-1,4-dihydro-2H-1lambda(6)-thia-4,5,8-triaza-anthracen-3-one (V), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxalin-2-one (VI), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxaline-2-thione (VII), and 7-hydroxy-1,4-dihydro-pyrazino[2,3-g]quinoxaline-2,3-dione (VIII). This strategy of integrating two benzofused privileged structures into one molecule may provide a greater chance for the discovery of novel lead compounds.

Antihelminthic activity of some newly synthesized 5(6)-(un)substituted-1H-benzimidazol-2-ylthioacetylpiperazine derivatives

Piperazine derivatives of 5(6)-substituted-(1H-benzimidazol-2-ylthio)acetic acids were synthesized by using two methods and studied for antihelminthic activity. The antiparasitic screening showed that compounds 18-24 exhibited higher activity against Trichinella spiralis in vitro in comparison to methyl 5-(propylthio)-1H-benzimidazol-2-yl-carbamate (albendazole). Most active were compounds 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-1H-benzimidazole 21 and 2-{[2-oxo-2-(4-benzhydrylpiperazin-1-yl)ethyl]thio}-5(6)-methyl-1(H)-benzimidazole 19 as well as 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-5(6)-methyl-1(H)-benzimidazole 23 with efficacy of 96.0%, 98.4% and 100%, respectively. The tested derivatives 15-19 and 20-23 were less active against Syphacia obvelata in vivo than albendazole and exhibited the same efficacy as piperazine, but in twice lower concentration.Compounds 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-1H-benzimidazole 21, 1,4-bis[(5(6)-methyl-1(H)-benzimidazol-2-ylthio)acetyl]piperazine 17 and 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-5(6)-methyl-1(H)-benzimidazole 23 had higher efficacies of 73%, 76%, and 77%, respectively.

Identification of novel, orally bioavailable spirohydantoin CGRP receptor antagonists

A rapid analogue approach to identification of spirohydantoin-based CGRP antagonists provided novel, low molecular weight leads. Modification of these leads afforded a series of nanomolar benzimidazolinone-based CGRP receptor antagonists. The oral bioavailability of these antagonists was inversely correlated with polar surface area, suggesting that membrane permeability was a key limitation to absorption. Optimization provided compound 12, a potent CGRP receptor antagonist (K(i)=21nM) with good oral bioavailability in three species.

Synthesis of Tetrahydrobenzimidazo[1,2-b]quinazolin-1(2H)-one and Tetrahydro-1,2,4-triazolo[5,1-b]quinazolin-8(4H)-one Ring Systems Under Solvent-Free Conditions

Tetraheterocyclic benzimidazo[1,2-a]quinazolin-4(1H)-one and tetrahydro-1,2,4-triazolo[5,1-b]quinazolin-8(4H)-one were synthesized in relatively high yields by the condensation reaction of an aldehyde and a cyclic beta-diketone with 2-aminobenzothiazole, 2-aminobenzimidazole or 3-amino-1,2,4-triazole without using any catalyst under solvent-free conditions.

Green route for the heterocyclization of 2-mercaptobenzimidazole into β-lactum segment derivatives containing –CONH– bridge with benzimidazole: Screening in vitro antimicrobial activity with various microorganisms

The efficient and rapid synthesis of novel azetidin-2-ones 4a-j has been established. Thus, both microwave and conventional condensation 2-{(1H-benzimidazol)-ylthio}-N'-2-(substituted phenyl) hydrazide with chloroacetylchloride were carried out in DMF-benzene solvent in the presence of Et(3)N catalyst. The microwave synthesis route afforded better yield with short time. The novel heterocycles were characterized by elemental analysis and spectral features. Some of the produced compounds were screened for their antimicrobial activity.

Exploring the limits of benzimidazole DNA-binding oligomers for the hypoxia inducible factor (HIF) site

The vascular endothelial growth factor (VEGF) and its receptors have been implicated as key-factors in tumor angiogenesis and are major targets in cancer therapy. New oligomers which mimic the architecture of DNA-binding polyamides have been designed to target the hypoxia inducible factor (HIF-1alpha) binding site on the promoter of VEGF gene. These oligomers incorporate an increasing number of six-five fused rings such as hydroxybenzimidazole-imidazole, benzimidazole-pyrrole, benzimidazole-chlorothiophene, and imidazopyridine-pyrrole, and bind the VEGF hypoxia response element (HRE) 5'-TACGT-3' with high affinity and selectivity.