Synthesis, characterization and cytotoxicity of some novel 1,3-disubstituted-2,3-dihydro-2-iminobenzimidazoles

Synthesis, characterization, antiproliferative activity, docking, and molecular dynamics simulation of new 1,3-dihydro-2H-benzimidazol-2-one derivatives

Cancer is a global public health problem that affects millions each year. Novel anticancer drug candidates are in need to treat various cancers and to overcome the resistance that exists against drugs in use. Benzimidazole derivatives have been reported as anticancer agents. These lead us to synthesize similar benzimidazole derivatives and investigate their anticancer activity. In this study, six new 1,3-dihydro-2H-benzimidazol-2-one-based molecules (2a-f) were synthesized. The structures of these molecules were verified by spectroscopic methods. The antiproliferative activities of molecules 2a-f were screened against a panel of human cancer cell lines, including the liver, colon, lung, and breast. The molecules were also tested towards normal human lung cell line to determine their selectivity. The results demonstrated that compound 2d had the highest cytotoxic effect compared to compounds 2a-c, 2e, and 2f against DLD-1 and MDA-MB-231 cell lines. The binding potential of the relatively active compound, 2d, with three targets was investigated through molecular docking. The stability of target-compound complexes procured from the docking was explored through molecular dynamics (MD) simulation. The docking and MD simulation studies revealed that compound 2d had the highest potential to bind to GALR3 among the targets. Furthermore, the computational pharmacokinetic study demonstrated that the synthesized compounds had drug-like properties.Communicated by Ramaswamy H. Sarma.

N-substitution Reactions of 2-Aminobenzimidazoles to Access Pharmacophores

Benzimidazole (BI) and its derivatives are interesting molecules in medicinal chemistry because several of these compounds have a diversity of biological activities and some of them are even used in clinical applications. In view of the importance of these compounds, synthetic chemists are still interested in finding new procedures for the synthesis of these classes of compounds. Astemizole (antihistaminic), Omeprazole (antiulcerative), and Rabendazole (fungicide) are important examples of compounds used in medicinal chemistry containing BI nuclei. It is interesting to observe that several of these compounds contain 2-aminobenzimidazole (2ABI) as the base nucleus. The structures of 2ABI derivatives are interesting because they have a planar delocalized structure with a cyclic guanidine group, which have three nitrogen atoms with free lone pairs and labile hydrogen atoms. The 10-π electron system of the aromatic BI ring conjugated with the nitrogen lone pair of the hexocyclic amino group, making these heterocycles to have an amphoteric character. Synthetic chemists have used 2ABI as a building block to produce BI derivatives as medicinally important molecules. In view of the importance of the BIs, and because no review was found in the literature about this topic, we reviewed and summarized the procedures related to the recent methodologies used in the N-substitution reactions of 2ABIs by using aliphatic and aromatic halogenides, dihalogenides, acid chlorides, alkylsulfonic chlorides, carboxylic acids, esters, ethyl chloroformates, anhydrides, SMe-isothioureas, alcohols, alkyl cyanates, thiocyanates, carbon disulfide and aldehydes or ketones to form Schiff bases. The use of diazotized 2ABI as intermediate to obtain 2-diazoBIs was included to produce Nsubstituted 2ABIs of pharmacological interest. Some commentaries about their biological activity were included.

Asymmetric organocatalysis: an enabling technology for medicinal chemistry

The efficacy and synthetic versatility of asymmetric organocatalysis have contributed enormously to the field of organic synthesis since the early 2000s. As asymmetric organocatalytic methods mature, they have extended beyond the academia and undergone scale-up for the production of chiral drugs, natural products, and enantiomerically enriched bioactive molecules. This review provides a comprehensive overview of the applications of asymmetric organocatalysis in medicinal chemistry. A general picture of asymmetric organocatalytic strategies in medicinal chemistry is firstly presented, and the specific applications of these strategies in pharmaceutical synthesis are systematically described, with a focus on the preparation of antiviral, anticancer, neuroprotective, cardiovascular, antibacterial, and antiparasitic agents, as well as several miscellaneous bioactive agents. The review concludes with a discussion of the challenges, limitations and future prospects for organocatalytic asymmetric synthesis of medicinally valuable compounds.

Recent Progress of Benzimidazole Hybrids for Anticancer Potential

This review presents the detailed account of factors leading to cancer and design strategy for the synthesis of benzimidazole derivatives as anticancer agents. The recent survey for cancer treatment in Cancer facts and figures 2017 American Chemical Society has shown progressive development in fighting cancer. Researchers all over the world in both developed and developing countries are in a continuous effort to tackle this serious concern. Benzimidazole and its derivatives showed a broad range of biological activities due to their resemblance with naturally occurring nitrogenous base i.e. purine. The review discussed benzimidazole derivatives showing anticancer properties through a different mechanism viz. intercalation, alkylating agents, topoisomerases, DHFR enzymes, and tubulin inhibitors. Benzimidazole derivatives act through a different mechanism and the substituents reported from the earlier and recent research articles are prerequisites for the synthesis of targeted based benzimidazole derivatives as anticancer agents. The review focuses on an easy comparison of the substituent essential for potency and selectivity through SAR presented in figures. This will further provide a better outlook or fulfills the challenges faced in the development of novel benzimidazole derivatives as anticancer.

Tautomeric and non-tautomeric N-substituted 2-iminobenzimidazolines as new lead compounds for the design of anti-influenza drugs: An in vitro study

A series of 1,3-disubstituted 2-iminobenzimidazolines as well as a number of their tautomeric analogs were synthesized. The synthesized compounds were tested for their cytotoxicity against MDCK cells and for inhibiting activity against influenza virus A/California/07/09 (H1N1)pdm09. Based on the results obtained, 50% cytotoxic concentration (CC₅₀), 50% inhibiting concentration (IC₅₀) and selectivity index (SI) were calculated for each compound. It was found that some of synthesized benzimidazole derivatives (7 of 22, 32%) possess strong virus-inhibiting activity against pandemic influenza virus (IC₅₀'s in low micromolar range) with quite moderate cytotoxicity (CC₅₀ in the range of thousands micromoles). Due to their high selectivity (highest SI's=50-83) these compounds are of significant interest for further in vivo experiments as well as for further structural optimization and drug development.

Structure-activity relationship (SAR) study and design strategies of nitrogen-containing heterocyclic moieties for their anticancer activities

The present review article offers a detailed account of the design strategies employed for the synthesis of nitrogen-containing anticancer agents. The results of different studies describe the N-heterocyclic ring system is a core structure in many synthetic compounds exhibiting a broad range of biological activities. Benzimidazole, benzothiazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, triazoles, quinolines and quinazolines including others drugs containing pyridazine, pyridine and pyrimidines are covered. The following studies of these compounds suggested that these compounds showed their antitumor activities through multiple mechanisms including inhibiting protein kinase (CDK, MK-2, PLK1, kinesin-like protein Eg5 and IKK), topoisomerase I and II, microtubule inhibition, and many others. Our concise representation exploits the design and anticancer potency of these compounds. The direct comparison of anticancer activities with the standard enables a systematic analysis of the structure-activity relationship among the series.

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.