The most satisfactory method for the synthesis of 2alkylbenzimidazoles 3, r alkyl was developed by phillips2425, which involves refluxing equimolar quantities of the. Benzimidazole derivatives have attracted a significant attention in recent years because of their medicinal applications as antiviral, antiulcer, antifungal, antihypertensive, anticancer, and antihistamine compounds. Iodine is a commercial and environmentally benign catalyst. Herein, two series of thiosemicarbazone and hydrazonebased benzimidazoles have been explored, by derivatizing 5acetyl benzimidazoles previously reported by us. In this method, ophenylenediamines were condensed with bisulfite adducts of various aldehydes and dialdehydes under neat conditions by microwave heating. In continuation, on the synthesis of heterocycles,14 and on the development of synthetic methodologies,1517 we herein report a facile method for the synthesis of benzimidazoles by the condensation of 1, 2phenylenediamine with carbonyl compounds, in the presence of ammonium salts in very good yields. New, improved conditions have been developed and optimized for the synthesis of benzimidazoles by intramolecular palladiumcatalyzed arylamination chemistry. A new route for the synthesis of 2mercapto benzimidazoles. Generally, the condensation of ophenylene diamine with carboxylic acids and their nitrile, imidates and orthoester 8 derivatives have been widely used for benzimidazole synthesis. The structures of the synthesized compounds were confirmed by ir, 1h. Benzimidazole definition of benzimidazole by medical. Benzimidazoles from ophenylene diamine with mandelic acid. Previously we developed a large variety of benzimidazole derivatives able to inhibit these viruses.
Synthesis, characterization, and applications supervising professor. Synthesis of some 6flouro5substituted benzimidazole 12 were reported by alagoz et al. A green and efficient strategy for the synthesis of benzoxazoles, benzothiazoles and benzimidazoles has been developed by using inexpensive, readily available, dioxygenstable and recyclable cufe 2 o 4 as the nanocatalyst, and osubstituted aminobenzene and various aldehydes as the starting materials. The reaction is catalyzed by pincer complexes of earthabundant cobalt under basefree conditions. Till date numerous reports especially on the synthesis of 2arylbenzimidazoles have been published but lack of knowledge on the detailed synthetic reports of two important derivatives such as. Respiratory rna viruses are responsible for recurrent acute respiratory illnesses that still represent a major medical need. Imidazole and benzimidazole synthesis is a comprehensive survey of the known methods of syntheses and ring modification. The synthesis of dicationic extended bisbenzimidazoles. Benzimidazole definition of benzimidazole by the free. Several analogues exhibited low micromolar minimal inhibitory concentrations mic against both grampositive and gramnegative bacteria of clinical relevance and could serve as leads for. Synthesis of benzimidazoles from amino acids with solvent.
A4, q and j have the meanings indicated in the claims. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are. Synthesis and pharmacological profile of benzimidazoles. Synthesis and biological activity of novel 2, 5disubstituted. A ring system composed of a benzene ring fused with an imidazole ring. For example, kamble and bhanage reported an improved method to form benzimidazoles from ophenylenediamines and dmf, respectively. Novel synthesis of benzoxazoles and benzimidazoles. The target diamidines show significant in vitro activity against b.
Facile and efficient onepot synthesis of benzimidazoles. Synthesis and biological activities of some benzimidazoles. The research presented in this thesis is centered on the design and synthesis of molecules which are derived from benzimidazoles and their applications. Benzoxazoles and benzimidazoles are important fused nitrogencontaining heterocycles present in a wide range of. Synthesis of benzimidazoles the synthesis of benzimidazole derivatives starts from biology 35417 at interamerican san german.
Benzimidazoles article about benzimidazoles by the free. Anxiety is a psychological and physiological state characterized by cognitive, somatic, emotional, and behavioral components. Benzimidazoles are a class of heterocyclic, aromatic compounds which share a fundamental structural characteristic of sixmembered benzene. Wed like to understand how you use our websites in order to improve them. Facile and efficient onepot synthesis of benzimidazoles using. In 1995, bourguignon reported the treatment of ophenylenediamines with dmf for the synthesis of benzimidazoles in the presence of sicl 4 in ch 2 cl 2. Us8188282b2 regioselective palladium catalyzed synthesis. Benzimidazoles heterocyclic building blocks sigmaaldrich. Synthesis and photophysical characterizations of thermal. A set of six novel benzimidazoles compounds were prepared, this includes 5.
This new synthetic method is simple, practical and cost saving, and tolerates wide functional groups. The synthesis of benzimidazoles derivative involves subsequent synthesis of 42chloroethoxybenzaldehyde, 4 methyl benzaldehyde. The procedure is very simple and the products are isolated with an easy workup in goodtoexcellent yields. Efficient and inexpensive synthesis of benzimidazoles and. The synthesis and chemistry of certain anthelmintic. Efficient and inexpensive synthesis of benzimidazoles and quinoxalines. The synthesis of benzimidazoles derivative involves subsequent synthesis of 42chloroethoxybenzaldehyde, 4 methyl benzaldehyde followed by benzimidazoles derivative by reaction between amines derivatives and ophenylenediamine in dimethyl farmamide dmf as solvent in the presence of iodine as a catalyst. Us3406178a us42916165a us3406178a us 3406178 a us3406178 a us 3406178a us 42916165 a us42916165 a us 42916165a us 3406178 a us3406178 a us 3406178a authority us united states prior art keywords aldehyde nitroaniline catalyst reaction carboxylic acid prior art date 19640204 legal status the legal status is an assumption and is not a legal conclusion. Benzimidazole, a heterocyclic aromatic organic compound consisting of a fusion of benzene and imidazole, in an extension of the wellelaborated imidazole system, has been used as a carbon skeleton for n heterocyclic carbenes, usually used as ligand for transition metal complexes. A series of novel benzimidazole derivatives were synthesized via parallel solutionphase chemistry.
The reaction mixture was stirred on magnetic stirrer for four hrs. A simple and efficient procedure for the synthesis of benzimidazoles using air as the oxidant. This reaction has a wide substrate scope, and the bail gel represents a new catalyst for the synthesis of benzoxazoles, benzimidazoles, and benzothiazoles. Author links open overlay panel sadaf azeez a popuri sureshbabu a priyanka chaudhary a shahulhameed sabiah b jeyakumar. Expedient synthesis of benzimidazoles using amides rsc. An efficient oxidative protocol enables the synthesis of multisubstituted or fused tetracyclic benzimidazoles via a metalfree oxidative cn coupling between the sp 3 ch and free nh of readily available n 1benzylalkyl1,2phenylenediamines in the presence of oxygen and tempo. Herein, we present the basemetalcatalyzed dehydrogenative coupling of primary alcohols and aromatic diamines to selectively form functionalized 2substituted benzimidazoles, liberating water and hydrogen gas as the sole byproducts.
Microwaveassisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Here, the synthesis of both classes of compounds starting from aromatic diamines and alcohols benzimidazoles or diols quinoxalines is reported. Direct synthesis of benzimidazoles by dehydrogenative. In the present report an efficient, rapid, facile and inexpensive route for the synthesis of benzimidazoles using 1,2arylenediamines and n,ndimethylformamide in acidic medium under thermalmicrowave condition is developed. As a kind of na tur al biolo gical r esour ce with physiolo gical acti vities, inexpensive amino acids are extensively used in. Synthesis of benzimidazoles the synthesis of benzimidazole. The synthesis of eight pyridazino1,6 abenzimidazoles by a novel synthetic route is described. A heterocyclic compound, c7h6n2, that is used in organic synthesis and inhibits the growth of certain fungi. Therefore, more and more inter ests ha ve been ar oused to the synthesis of benzimidazole and its derivatives recently411.
Imidazole glyoxaline, 1,3diazole a heterocyclic base. This is a general method of preparing benzimidazoles. Synthetic approaches to benzimidazoles from ophenylenediamine. Pdf benzimidazole derivatives are versatile nitrogen containing heterocyclic compounds which have long been known as a. Pharmacological compounds of benzimidazole derivatives are potent inhibitors for a variety of enzymes. Silica sulfuric acid sio 2 oso 3 h as an ecofriendly, readily available, and reusable catalyst is applied to benzimidazole derivatives synthesis under reflux in ethanol. This relatively unexplored heterocyclic ring system is readily accessible starting from benzoylpropionic acids and phenylhydrazines in five steps. Us3406178a preparation of 2substituted benzimidazoles. Almost all syntheses of benzimidazoles start with benzene derivatives possessing nitrogencontaining functions ortho to.
A new convenient method for preparation of 2substituted benzimidazoles and bisbenzimidazoles is presented. The results were also compared with results of synthesis by conventional heating under reflux. Sulfurdabco promoted reductive couplingannulation cascade reaction between ohydroxyamino nitrobenzenes and benzaldehydes. Only ortho substituted acid possess both high affinity for the aii receptor and oral antihypertensive potency. The methods for the synthesis of benzimidazoles have become a focus of synthetic. Imidazolium chloridecatalyzed synthesis of benzimidazoles. Many of these compounds were found to inhibit the growth of staphylococcus aureus and escherichia coli. This methodology, combined with a catch and release purification strategy, has led to a range of these heterocycles being prepared rapidly and in. Phenylenediamine via nanoparticles and green strategies using transition metal catalysts sugandha singhal. The synthesis and chemistry of certain anthelmintic benzimidazoles lb.
At the same time, many simple benzimidazoles are key intermediates in organic synthesis. The cufe 2 o 4 nanoparticles are dioxygen insensitive and easily recoverable with an external. Pdf synthesis of benzimidazole derivatives and study of their. Some of the synthesized compounds showed moderate activity against tested fungi ansari and lal, 2009a, ansari and lal, 2009b. Magnetically recoverable and reusable cufe2o4 nanoparticle. Synthesis, characterization, and biological evaluation of. The synthesized benzimidazoles compounds were prepared from the condensation reaction between ophenylenediamine and various carbonyl compounds, in. It brings together the multitude of synthesis of the imidazole ring in a systemic way interms of specific bond formation, and recommends the most attractive synthetic approaches. Various catalyzed synthesis of benzimidazole derivatives are known condensation of ophenylenediamine with ortho esters in the presence of. Copperincorporated fluorapatite encapsulated iron oxide. Synthesis and biological activities of some benzimidazoles derivatives. An improved procedure for the synthesis of benzimidazoles. The present invention provides a direct palladium catalyzed, regioselective process to a wide variety of unsymmetrical, multifunctional nsubstituted benzimidazoles or azabenzimidazoles of.
The first chapter provides an introduction to benzimidazoles and nheterocyclic carbenes, a unique class of molecules derived from benzimidazoles. Recent trends in the synthesis of benzimidazoles from o. Mild and efficient protocol for the synthesis of benzimidazoles using samarium triflate. The present invention relates to a process for the regioselective synthesis of compounds of the formula i, wherein r0. The synthesized cond exhibited compound exhibited significant of microbiological activity. In view of their wide ranging activities, the synthesis of benzimidazoles and its derivatives remain a primary focus for synthetic chemistry communities. Wise a basis for interest in the benzimidazole ring system as a nucleus from which to develop potential chemotherapeutic agents was established in the i95os when it was found that 5,6dimethyl i. Since then, a large number of benzimidazoles have been synthesized from 1 and aliphatic acids2023.
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