Glyoxylic acid as catalyst:A simple selective synthesis of 1,2-disubstituted benzimidazoles in aqueous media

Glyoxylic acid （5 mol%） performs as a novel highly water-soluble catalyst for the synthesis of 2-aryl-l-arylmethyl-lH- benzimidazoles from a wide range of substituted o-phenylenediamines and various substituted aldehydes in good to excellent isolated yields （85-95%） using water as solvent at ambient temperature. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster （20--40 rain） reactions and excellent yields of products.

Lithium bromide catalyzed solvent free method for synthesis of 2-substituted benzimidazoles and imidazopyridines

The first successful lithium bromide mediated solvent free condensation of arylenediamine and esters to obtain 2-substituted benzimidazole and imidazopyridine in good to excellent yields is described.

Solventless synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles catalyzed by Fe(ClO_4)_3 at room temperature

A series of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles was synthesized expeditiously in good yields from o-phenylenediamines and aldehydes in the presence of Fe（ClO4）3 without solvent at room temperature.

Synthesis of Multifunctionalised 2-Substituted Benzimidazoles Using Copper (II) Hydroxide as Efficient Solid Catalyst

Here we demonstrate the synthesis of multifunctionalised benzimidazoles through the coupling of o-phenylenediamine with aldehydes by using Copper (II) hydroxide as an efficient solid catalyst in methanol at room temperature. The Copper (II) hydroxide solid catalyst gave better yields (80%-99%) in short reaction time (4-8 h). These commercially available cheap catalysts are more active than many reported expensive heterogeneous catalysts. Using the Copper hydroxide fresh catalyst, the yield of product 3a was 98%, while the recovered catalyst in the three subsequent cycles gave the yield of 94%, 90% and 88% respectively.

Green and High Efficient Synthesis of 2-Aryl Benzimidazoles: Reaction of Arylidene Malononitrile and 1,2-Phenylenediamine Derivatives in Water or Solvent-Free Conditions

A fast, high efficiency and environmentally friendly procedure for the synthesis of 2-aryl benzim-idazole derivatives has been reported. Reaction between 1,2-phenylenediamine derivatives and arylidene malononitrile under aqueous media and also solvent-free conditions generates 2-aryl benzimidazole derivatives with a high yield.

Synthesis, Electrochemistry and Antitumor Activity of 1’H, 3’H(Me)-spiro-[(aza)benzimidazoline-2’, 3-(1,2-diferrocenylcyclopropenes)], 2-(1,2-Diferrocenylvinyl)benz- and Azabenzimidazoles

A new method of synthesis of 2-(1,2-diferrocenylvinyl)benz- and azabenzimidazoles (3a-f), (4a-f) and 1’H,3’H(Me)-spiro-[(aza)benzimidazoline-2’,3-(1,2-diferrocenylcyclopropenes)] (5a-f) via reactions of diferrocenyl(methylsulfanyl)cyclopropenylium iodide (1) with aromatic o-diamines (2a-f) in the presence of Et3N (80°C - 82°C) is described. The structures of the resultant compounds are established using IR, 1H and 13C NMR spectroscopy, mass spectrometry and elemental analysis. The structure of one compound, cis-2-(1,2-diferrocenylvinyl)-1-methylbenzimidazole (3b), is confirmed by X-ray diffraction analysis. The electrochemical properties of compounds 3a, 3b, 3d and 5f are investigated using cyclic square wave voltammetry. Two electrochemical processes (I-II), attributed to oxidation of the ferrocene moieties, and the values of E0’(I), E0’(II), DE0’(II-I) and comporportionation constant Kcom are reported. The bioactivities of seven compounds 3a, 3c-f, 5d, 5f are evaluated. Compound 5f is the most active compound with a modest cytotoxic activity against six human cancer cell lines: U-251 (glioma), PC-3 (prostate cancer), K-562 (leukemia), HCT-15 (colon cancer), MCF-7 (breast cancer) and SKLU-1 (lung cancer).

Efficient Syntheses of 2-Substituted Benzimidazoles and Benzoxazoles from β-Keto Esters

An efficient synthetic method was developed to synthesize 2-substituted benzimidazoles and benzo- xazoles with β-keto esters as starting materials under mild reaction conditions, during which other functional groups are bearable from reactants to products.

Electrochemical and Theoretical Studies of 1-Alkyl-2-substituted Benzimidazoles as Corrosion Inhibitors for Carbon Steel Surface in HCl Medium

The inhibition efficiencies of newly synthesized four 1-alkyl-2-substituted benzimidazole compounds（a^d） have been studied for the corrosion of carbon steel in 1.0 M HCl by using potentiodynamic polarization measurement. The four inhibitors act as mixed-type inhibitors,which mainly inhibit cathodes. The inhibition efficiency of these compounds enhanced when the concentration of the inhibitors increased. A theoretical study of the corrosion inhibition efficiency of these compounds was carried out by using the B3 LYP level with the 6-31＋G＊ basis set. Considering the solvent effect,the IEFPCM model was selected. Furthermore,the adsorption energies of the inhibitors with the iron（001） surface were studied by using molecular dynamic（MD） simulations. The theoretical results show that these inhibitors all exhibit several adsorption active-centers. Meanwhile,the MD simulations indicate that the adsorption occurs mostly through benzene ring and the lone pair electrons of the nitro atoms. These results demonstrated that the theoretical studies and MD simulations are reliable and promising methods for analyzing the inhibition efficiency of organic inhibitors.

DMP(1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one):A novel catalyst for synthesis of 2-substituted benzimidazoles derivatives

Various 2-arylbenzimidazoles were synthesized from o-phenylenediamine and aldehydes via one-step process using DMP （Dess-Martin-periodinane） reagent as an oxidant. The method was proved to be simple, convenient and the products were isolated with good yields （80-90%）. ？2009 Charansingh H. Gill. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Al-Pillared Ghassoulite Clay as a New Green Catalyst for the Synthesis of Benzothiazoles and Benzimidazoles: Effect of Amine/CEC Ratio

The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that substantial portions of the text came from other published papers. The scientific community takes a very strong view on this matter, and the International Journal of Organic Chemistry treats all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.2, 151-157 (pages), 2013, has been removed from this site. Title: Al-Pillared Ghassoulite Clay as a New Green Catalyst for the Synthesis of Benzothiazoles and Benzimidazoles: Effect of Amine/CEC Ratio Authors: Rachid Azzallou,?Rachid Mamouni,?Kimberly Stieglitz,?Nabil Saffaj, Mohammadine Said

A New Efficient Synthesis of Bisphenol A Diether Bis-imidazoles and Bis-benzimidazoles

A new efficient synthesis of bisphenol A diether bis-imidazoles and bis-benzimidazoles by bromoalkylation and imidazolylation or benzimidazolylation two-step reactions from commercial bisphenol A, imidazole, 2-methylimidazole and benzimidazole is reported.

Synthesis of Mono- and Di-fluorinated Benzimidazoles

Three efficient methods to synthesize mono- and di-fluorinated benzimidazoles are reported. These methods provide 5-amino-6-fluoro-benzimidazoles （5）, 5,7-difluoro-benzimidazoles （10）, and 6-fluoro-benzimidazoles （13） starting from commercially available 1,5-difluoro-2,4-dinitrobenzene （DFDNB）, 2,3,4,5-tetrafluoro-6-nitrobenzoic acid （TFNBA）, and 2,4-difluoro-l-nitrobenzene （DFNB）, respectively.

Expeditious and Efficient Synthesis of Benzoxazoles, Benzothiazoles, Benzimidazoles Catalyzed by Ga（OTf）3 under Solvent-Free Conditions

A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga（OTf）3 under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.

Selective Synthesis of 2-Aryl-l-benzylated-1 H-benzimidazoles

An efficient and simple procedure was developed for the green synthesis of various 2-aryl-l-ben- zylated-1H-benzimidazoles in high yields by condensation of o-phenylenediamine with aldehydes with P2O5/SiO2 as catalyst under solvent-free and ambient conditions.

Cobalt nitride enabled benzimidazoles production from furyl/aryl bio-alcohols and o-nitroanilines without an external H-source

Benzimidazole derivatives have wide-spectrum biological activities and pharmacological effects,but remain challenging to be produced from biomass feedstocks.Here,we report a green hydrogen transfer strategy for the efficient one-pot production of benzimidazoles from a wide range of bio-alcohols and o-nitroanilines enabled by cobalt nitride species on hierarchically porous and recyclable nitrogen-doped carbon catalysts(Co/CN_(x)-T,T denotes the pyrolysis temperature)without using an external hydrogen source and base additive.Among the tested catalysts,Co/CN_(x)-700 exhibited superior catalytic performance,furnishing 2-substituted benzimidazoles in 65%–92%yields.Detailed mechanistic studies manifest that the coordination between Co^(2+)and N with appropriate electronic state on the porous nitrogen-doped carbon having structural defects,as well as the remarkable synergetic effect of Co/N dual sites contribute to the pronounced activity of Co/CN_(x)-700,while too high pyrolysis temperature may cause the breakage of the catalyst Co-N bond to lower down its activity.Also,it is revealed that the initial dehydrogenation of bio-alcohol and the subsequent cyclodehydrogenation are closely correlated with the hydrogenation of nitro groups.The catalytic hydrogen transfer-coupling protocol opens a new avenue for the synthesis of N-heterocyclic compounds from biomass.

Synthesis of 2-arylbenzimidazoles and 2-arylbenzothiazoles in both room temperature and microwave condition catalyzed by hexamethylenetetramine-bromine complex

One-pot condensation of 2-aminothiophenol or 1,2-phenylenediamine with different aldehydes has been catalyzed by hexamethylenetetramine-bromine（HMTA-Bromine） as new,available and effective catalyst.2-Arylbenzo thiazoles and 2-aryl benzimidazoles have been achieved in excellent yield and good purity.

Xanthan Sulfuric Acid： An Efficient Bio-supported and Recy- clable Solid Acid Catalyst for the Synthesis of 2-Aryl Thiadiazolo Benzimidazoles

Xanthan sulfuric acid is an efficient solid acid catalyst for the preparation of 2-aryl benzimidazoles in excellent yields. This method is applicable for the reaction of benzo[c][ 1,2,5]thiadiazole-4,5-diamine with aldehydes by sim- ple physical grinding at room temperature. The salient features of the present methodology is cheaper process, easy synthesis of stable catalyst and the catalyst can be easily recycled without significant loss of activity.

Cu（I）-Catalyzed Synthesis of 2-Substituted Benzimidazoles from 2-lodoanilines and Amides

A novel and efficient approach to the synthesis of 2-substituted benzimidazoles has been developed via CuI/DMEDA-catalyzed coupling reaction and post-cyclization with glacial acetic acid from readily available 2-iodoanilines and amides. This method is suitable for the construction of a variety of benzimidazoles in moderate to good yields under short reaction times.

Rational hapten design and establishment of broad-spectrum indirect competitive enzyme-linked immunosorbent assay for benzimidazoles monitoring in milk

Objectives Benzimidazoles(BZs)are commonly used for the treatment of soil-transmitted helminth infections in veterinary clinics;however,misuse and overdosing of BZs will cause residual problems and have the potential to damage human health through the food chain.Thus,the existence of BZs in foods needs more attention.This study aims to establish a broad-spectrum immunoassay for rapid detection and to simultaneously monitor BZs in milk.Materials and Methods Based on structure analysis,a‘zero epitope loss’strategy,which introduced a spacer arm into the imino group of the imidazole ring of albendazole,was first adopted for hapten modification to obtain an ultra-sensitive and broad-spectrum antibody.An indirect competitive enzyme-linked immunosorbent assay(icELISA)was established for the detection of 18 BZs in milk sample with a single-step pretreatment.A quantitative structure–activity relationship model was constructed to interpret and predict the recognition.Results The antibody could recognize 20 BZs and the half-inhibitory concentrations ranged from 0.054 to 417.58 ng/mL,the limits of detection of icELISA ranged from 0.4 to 89.4 ng/mL,and the mean recovery rates ranged from 76.49%to 120.40%,with a coefficient of variation<20%.Substituent R1 of BZs was considered to be the main influencing factor for recognition,and the comparative molecular field analysis model(q2=0.724,r2=0.998)was finally chosen for further prediction.Conclusions The results indicated that the established icELISA could simultaneously identify 18 BZs,with good accuracy and precision,which was suitable for rapid detection of BZs in milk.

An Efficient and Convenient Synthesis of Imidazolines and Benzimidazoles via Oxidation of Carbon-Nitrogen Bond in Water Media

The metal coordination complex K4[Fe（CN）6] is an efficient and environmentally benign catalyst for the syn- thesis of imidazolines and benzimidazoles from various aldehydes and 1,2-diamines in aqueous medium at room temperature. This protocol gives excellent yield of product with desired purity.