First synthesis of an aziridinyl fused pyrrolo[1,2-a]benzimidazole and toxicity evaluation towards normal and breast cancer cell lines

Advances in the Synthesis of Ring-Fused Benzimidazoles and Imidazobenzimidazoles

This review article provides a perspective on the synthesis of alicyclic and heterocyclic ring-fused benzimidazoles, imidazo[4,5-f]benzimidazoles, and imidazo[5,4-f]benzimidazoles. These heterocycles have a plethora of biological activities with the iminoquinone and quinone derivatives displaying potent bioreductive antitumor activity. Synthesis is categorized according to the cyclization reaction and mechanisms are detailed. Nitrobenzene reduction, cyclization of aryl amidines, lactams and isothiocyanates are described. Protocols include condensation, cross-dehydrogenative coupling with transition metal catalysis, annulation onto benzimidazole, often using CuI-catalysis, and radical cyclization with homolytic aromatic substitution. Many oxidative transformations are under metal-free conditions, including using thermal, photochemical, and electrochemical methods. Syntheses of diazole analogues of mitomycin C derivatives are described. Traditional oxidations of o-(cycloamino)anilines using peroxides in acid via the t-amino effect remain popular.

An approach towards the synthesis of novel fused nitrogen tricyclic heterocyclic scaffolds via GBB reaction

A concise and efficient one-pot synthesis of novel N-fused tricyclic derivatives has been developed by using the Groebke–Blackburn–Bienaymé (GBB) reaction, which involved the reaction of 3-amino-1H-indazoles, aldehydes and isonitriles to afford 2-aryl-5H-imidazo[1,2-b]indazol-3-amine derivatives via a formal [4 + 1] cycloaddition reaction.

Synthesis, Crystal Study, and Anti-Proliferative Activity of Some 2-Benzimidazolylthioacetophenones towards Triple-Negative Breast Cancer MDA-MB-468 Cells as Apoptosis-Inducing Agents

On account of its poor prognosis and deficiency of therapeutic stratifications, triple negative breast cancer continues to form the causative platform of an incommensurate number of breast cancer deaths. Aiming at the development of potent anticancer agents as a continuum of our previous efforts, a novel series of 2-((benzimidazol-2-yl)thio)-1-arylethan-1-ones 5a–w was synthesized and evaluated for its anti-proliferative activity towards triple negative breast cancer (TNBC) MDA-MB-468 cells. Compound 5k was the most active analog against MDA-MB-468 (IC₅₀ = 19.90 ± 1.37 µM), with 2.1-fold increased activity compared to 5-fluorouracil (IC₅₀ = 41.26 ± 3.77 µM). Compound 5k was able to induce apoptosis in MDA-MB-468, as evidenced by the marked boosting in the percentage of florecsein isothiocyanate annexin V (Annexin V–FITC)-positive apoptotic cells (upper right (UR) + lower right (LR)) by 2.8-fold in comparison to control accompanied by significant increase in the proportion of cells at pre-G1 (the first gap phase) by 8.13-fold in the cell-cycle analysis. Moreover, a quantitative structure activity relationship (QSAR) model was established to investigate the structural requirements orchestrating the anti-proliferative activity. Finally, we established a theoretical kinetic study.

Facile synthesis of functionalized 6-cyano-2-oxa-7-azabicyclo[4.1.0]hept-3-en-1-yl acetates: a catalyst free approach to access the pyran fused 2-acetoxy-NH-aziridines

Novel pyran fused 2-acetoxy-NH-aziridine scaffold was constructed by reacting the enamine fragment of 4-H-pyrans and spiropyrans using iodobenzene diacetate under catalyst free environment.

Green, efficient and large-scale synthesis of benzimidazoles, benzoxazoles and benzothiazoles derivatives using ligand-free cobalt-nanoparticles: as potential anti-estrogen breast cancer agents, and study of their interactions with estrogen receptor by molecular docking

A facile and high yielding method for the synthesis of 2-aryl benzoxazoles, benzimidazole and benzothiazoles is reported employing cobalt oxide nanoparticles.

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.

Benzimidazoles diminish ERE transcriptional activity and cell growth in breast cancer cells

Estrogen receptors (ERα and ERβ) are members of the nuclear receptor superfamily. They regulate the transcription of estrogen-responsive genes and mediate numerous estrogen related diseases (i.e., fertility, osteoporosis, cancer, etc.). As such, ERs are potentially useful targets for developing therapies and diagnostic tools for hormonally responsive human breast cancers. In this work, two benzimidazole-based sulfonamides originally designed to reduce proliferation in prostate cancer, have been evaluated for their ability to modulate growth in estrogen dependent and independent cell lines (MCF-7 and MDA-MB 231) using cell viability assays. The molecules reduced growth in MCF-7 cells, but differed in their impact on the growth of MDA-MB 231 cells. Although both molecules reduced estrogen response element (ERE) transcriptional activity in a dose dependent manner, the contrasting activity in the MDA-MB-231 cells seems to suggest that the molecules may act through alternate ER-mediated pathways. Further, the methyl analog showed modest selectivity for the ERβ receptor in an ER gene expression array panel, while the naphthyl analog did not significantly alter gene expression. The molecules were docked in the ligand binding domains of the ERα-antagonist and ERβ-agonist crystal structures to evaluate the potential of the molecules to interact with the receptors. The computational analysis complimented the results obtained in the assay of transcriptional activity and gene expression suggesting that the molecules upregulate ERβ activity while down regulating that of ERα.

An efficient and facile synthesis of benzimidazo[1,2-a]benzimidazoles via copper-catalyzed domino addition/double cyclization

A variety of benzimidazo[1,2-a]benzimidazole derivatives were efficiently and facilely assembled from bis-(o-haloaryl)carbodiimides and primary amines through a Cu-catalyzed domino addition/double cyclization process.

Benzofuran-, benzothiophene-, indazole- and benzisoxazole-quinones: excellent substrates for NAD(P)H:quinone oxidoreductase 1

A series of heterocyclic quinones based on benzofuran, benzothiophene, indazole and benzisoxazole has been synthesized, and evaluated for their ability to function as substrates for recombinant human NAD(P)H:quinone oxidoreductase (NQO1), a two-electron reductase upregulated in tumor cells. Overall, the quinones are excellent substrates for NQO1, approaching the reduction rates observed for menadione.

Synthesis, Characterization, and Crystal Structures of Bis-Imidazolium Salts and Respective Dinuclear Ag(I)N-Heterocyclic Carbene Complexes:In VitroAnticancer Studies against “Human Colon Cancer” and “Breast Cancer”

This paper describes synthesis, characterization (NMR, FT-IR, microanalysis, and X-ray crystallography),in vitroanticancer activity ofortho/para-xylyl linked bis-imidazolium salts (4-5) and respective dinuclear Ag(I)N-heterocyclic carbene (NHC) complexes (6-7). All the compounds were tested for their cytotoxicity against human colorectal cancer (HCT 116) and breast cancer (MCF-7) cell lines. According to cell viability measurements using MTT assay, all the complexes (6-7) showed a dose-dependent cytotoxic activity against both the cell lines, whereas respective salts (4-5) proved to be inactive. The complexes (6-7) demonstrated significant activity with IC50values range 5.6–20.3 μM for HCT 116 and 1.12–6.38 μM for MCF-7. 5-Fluorouracil was used as standard drug (IC50= 5.9 μM) for HCT 116, whereas tamoxifen was used as standard drug for MCF-7 (IC50= 14 μM) cell line.