Synthesis and biological evaluation of 5-arylamino-1H-benzo[d]imidazole-4,7-diones as inhibitor of endothelial cell proliferation

Various synthesis and biological evaluation of some tri -tetra-substituted imidazoles derivatives: A review

The imidazole nucleus represents a significant group of heterocyclic molecules with diverse significance in the modern world due to its exploration potential and various pharmacological applications. The relevance of imidazole and its derivatives has gained popularity in recent years, especially in the production of commercial drugs and the treatment of various conditions. The imidazole nucleus is present in many natural compounds and widely distributed in essential amino acids, such as l-histidine, whose derivatives exhibit powerful pharmacological properties. In this review, we delve into the historical timeline and development of synthetic pathways for tri- and tetra-substituted imidazoles used in the renowned Radziszewski reaction. Furthermore, we explore various bacteriological applications documented in the literature, as well as current advances in preclinical approaches to imidazole-based drug discovery. Tri- or tetra-substituted imidazole derivatives show strong potential for new synthesis methods, such as reflux or microwave, as well as various biological activities.

Highly Active Small Aminated Quinolinequinones against Drug-Resistant Staphylococcus aureus and Candida albicans

Two subseries of aminated quinolinequinones (AQQs, AQQ1-16) containing electron-withdrawing group (EWG) or electron-donating group (EDG) in aryl amine moiety were successfully synthesized. Antimicrobial activity assessment indicates that some of the AQQs (AQQ8-10 and AQQ12-14) with an EDG in aryl amine exhibited strong antibacterial activity against Gram-positive bacterial strains, including Staphylococcus aureus (ATCC^® 29213) and Enterococcus faecalis (ATCC^® 29212). In contrast, AQQ4 with an EWG in aryl amine displayed excellent antifungal activity against fungi Candida albicans (ATCC^® 10231) with a MIC value of 1.22 μg/mL. To explore the mode of action, the selected AQQs (AQQ4 and AQQ9) were further evaluated in vitro to determine their antimicrobial activity against each of 20 clinically obtained resistant strains of Gram-positive bacteria by performing antibiofilm activity assay and time-kill curve assay. In addition, in silico studies were carried out to determine the possible mechanism of action observed in vitro. The data obtained from these experiments suggests that these molecules could be used to target pathogens in different modes of growth, such as planktonic and biofilm.

Synthesis and Structure-Activity Relationship Studies of Benzimidazole-4,7-dione-Based P2X3 Receptor Antagonists as Novel Anti-Nociceptive Agents

P2X3 receptors (P2X3R) are ATP-gated ion channels predominantly expressed in C- and Aδ-fiber primary afferent neurons and have been introduced as a novel therapeutic target for neurological disorders, including neuropathic pain and chronic cough. Because of its localized distribution, antagonism of P2X3R has been thoroughly considered, and the avoidance of issues related to CNS side effects has been proven in clinical trials. In this article, benzimidazole-4,7-dione-based derivatives were introduced as a new chemical entity for the development of P2X3R antagonists. Starting from the discovery of a hit compound from the screening of 8364 random library compounds in the Korea Chemical Bank, which had an IC₅₀ value of 1030 nM, studies of structure–activity and structure–property relationships enabled further optimization toward improving the antagonistic activities as well as the drug’s physicochemical properties, including metabolic stability. As for the results, the final optimized compound 14h was developed with an IC₅₀ value of 375 nM at P2X3R with more than 23-fold selectivity versus P2X2/3R, along with properties of metabolic stability and improved solubility. In neuropathic pain animal models evoked by either nerve ligation or chemotherapeutics in male Sprague-Dawley rats, compound 14h showed anti-nociceptive effects through an increase in the mechanical withdrawal threshold as measured by von Frey filament following intravenous administration.

Imidazole as a Promising Medicinal Scaffold: Current Status and Future Direction

Various imidazole-containing compounds have been tested for their medical usefulness in clinical trials for several disease conditions. The rapid expansion of imidazole-based medicinal chemistry suggests the promising and potential therapeutic values of imidazole-derived compounds for treating incurable diseases. Imidazole core scaffold contains three carbon atoms, and two nitrogen with electronic-rich characteristics that are responsible for readily binding with a variety of enzymes, proteins, and receptors compared to the other heterocyclic rings. Herein, we provide a thorough overview of the current research status of imidazole-based compounds with a wide variety of biological activities including anti-cancer, anti-microbial, anti-inflammatory and their potential mechanisms including topoisomerase IIR catalytic inhibition, focal adhesion kinase (FAK) inhibition, c-MYC G-quadruplex DNA stabilization, and aurora kinase inhibition. Additionally, a great interest was reported in the discovery of novel imidazole compounds with anti-microbial properties that break DNA double-strand helix and inhibit protein kinase. Moreover, anti-inflammatory mechanisms of imidazole derivatives include inhibition of COX-2 enzyme, inhibit neutrophils degranulation, and generation of reactive oxygen species. This systemic review helps to design and discover more potent and efficacious imidazole compounds based on the reported derivatives, their ADME profiles, and bioavailability scores that together aid to advance this class of compounds.

Design, synthesis and investigation of the mechanism of action underlying anti-leukemic effects of the quinolinequinones as LY83583 analogs

Literature conclusively shows that one of the quinolinequinone analogs (6-anilino-5,8-quinolinequinone), referred to as LY83583 hereafter, an inhibitor of guanylyl cyclase, was used as the inhibitor of the cell proliferation in cancer cells. In the present work, a series of analogs of the LY83583 containing alkoxy group(s) in aminophenyl ring (AQQ1-15) were designed and synthesized via a two-step route and evaluated for their in vitro cytotoxic activity against four different cancer cell lines (K562, Jurkat, MT-2, and HeLa) and human peripheral blood mononuclear cells (PBMCs) by MTT assay. The analog (AQQ13) was identified to possess the most potent cytotoxic activity against K562 human chronic myelogenous (CML) cell line (IC₅₀ = 0.59 ± 0.07 μM) with significant selectivity (SI = 4.51) compared to imatinib (IC₅₀ = 5.46 ± 0.85 μM; SI = 4.60). Based on its superior cytotoxic activity, the analog AQQ13 was selected for further mechanistic studies including determination of its apoptotic effects on K562 cell line via annexin V/ethidium homodimer III staining potency, ABL1 kinase inhibitory activity, and DNA cleaving capacity. Results ascertained that the analog AQQ13 induced apoptosis in K562 cell line with notable DNA-cleaving activity. However, AQQ13 demonstrated weak ABL1 inhibition indicating the correlation between anti-K562 and anti-ABL1 activities. In continuance, respectively conducted in silico molecular docking and Absorption, Distribution, Metabolism, and Excretion (ADME) studies drew attention to enhanced binding interactions of AQQ13 towards DNA and its high compatibility with the potential limits of specified pharmacokinetic parameters making it as a potential anti-leukemic drug candidate. Our findings may provide a new insight for further development of novel quinolinequinone-based anticancer analogs against CML.

One-Pot Synthesis of Dihalogenated Ring-Fused Benzimidazolequinones from 3,6-Dimethoxy-2-(cycloamino)anilines Using Hydrogen Peroxide and Hydrohalic Acid

3,6-Dimethoxy-2-(cycloamino)anilines undergo 4- or 6-electron oxidations to afford novel ring-fused halogenated benzimidazoles or benzimidazolequinones using H₂O₂/HCl or H₂O₂/HBr. Cl₂ and Br₂ are capable of the same oxidative transformation to the benzimidazolequinones. Labeling experiments indicate that water is necessary for oxidation of the para-dimethoxybenzenes to the corresponding quinones.

Angiogenesis inhibitors identified by cell-based high-throughput screening: synthesis, structure-activity relationships and biological evaluation of 3-[(E)-styryl]benzamides that specifically inhibit endothelial cell proliferation

Proliferation of endothelial cells is critical for angiogenesis. We report orally available, in vivo active antiangiogenic agents which specifically inhibit endothelial cell proliferation. After identifying human umbilical vein endothelial cell (HUVEC) proliferation inhibitors from a cell-based high-throughput screening (HTS), we eliminated those compounds which showed cytotoxicity against HCT116 and vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitory activity. Evaluations in human Calu-6 xenograft model delivered lead compound 1. Following extensive lead optimization and alteration of the scaffold we discovered 32f and 32g, which both inhibited the proliferation and tube formation of HUVEC without showing inhibitory activity against any of 25 kinases or cytotoxicity against either normal fibroblasts or 40 cancer cell lines. Upon oral administration, 32f and 32g had good pharmacokinetic profiles and potent antitumor activity and decreased microvessel density (MVD) in Calu-6 xenograft model. Combination therapy with a VEGFR inhibitor enhanced the in vivo efficacy. These results suggest that 32f and 32g may have potential for use in cancer treatment.

Cellular Mechanism of Newly Synthesized Indoledione Derivative-induced Immunological Death of Tumor Cell

BACKGROUND

EY-6 is one of the newly synthesized indoledione derivatives to induce tumor cell-specific cell death. In this study, we investigated the mechanism of immunological death induced by EY-6 at mouse colon cancer cell as well as at the normal immune cell represented by dendritic cell.

METHODS

C57BL/6 mouse syngeneic colon cancer cell MC38 was treated with EY-6, and analyzed by MTT for viability test, flow cytometry for confirming surface expressing molecules and ELISA for detection of cytokine secretion. Normal myeloid-dendritic cell (DC) was ex vivo cultured from bone marrow hematopoietic stem cells of C57BL/6 mice with GM-CSF and IL-4 to analyze the DC uptake of dead tumor cells and to observe the effect of EY-6 on the normal DC.

RESULTS

EY-6 killed the MC38 tumor cells in a dose dependent manner (25, 50 and 100 µM) with carleticulin induction. And EY-6 induced the secretion of IFN-γ but not of TNF-α from the MC38 tumor cells. EY-6 did not kill the ex-vivo cultured DCs at the dose killing tumor cells and did slightly but not significantly induced the DC maturation. The OVA-specific cross-presentation ability of DC was not induced by chemical treatment (both MHC II and MHC I-restricted antigen presentation).

CONCLUSION

Data indicate that the EY-6 induced tumor cell specific and immunological cell death by modulation of tumor cell phenotype and cytokine secretion favoring induction of specific immunity eliminating tumor cells.

Studies on quinones. Part 46. Synthesis and in vitro antitumor evaluation of aminopyrimidoisoquinolinequinones

In the search of structure-activity relationship studies and to explore the antitumor effect associated with the pyrimidoisoquinolinequinone scaffold, several diversily substituted 8-aminopyrimido[4,5-c]isoquinolinequinones were regioselectively synthesized. Variation in the structure of the nitrogen substituent bonded to the 8-position of the pyrimidoisoquinolinequinone system led to a set of alkylamino-, phenylamino- and alkyphenylamino derivatives. The cytotoxic activity of the aminoquinone derivatives was evaluated in vitro using the MTT colorimetric method against one normal cell line (MRC-5 lung fibroblasts) and four human cancer cell lines (AGS human gastric adenocarcinoma; SK-MES-1 human lung cancer cells, and J82 human bladder carcinoma; HL-60 human leukemia) in 72-h drug exposure assays. Among the series, five compounds exhibited interesting antitumor activity against AGS human gastric adenocarcinoma and human lung cancer cells. The SAR studies revealed that both the nature of the nitrogen substituent into the quinone ring and the methyl group at the 6-position play key roles in the antitumor activity.

The influence of the aziridinyl substituent of benzimidazoles and benzimidazolequinones on toxicity towards normal and Fanconi anaemia cells

Aziridinyl substituted benzimidazolequinones are more toxic than methoxy analogues towards normal human fibroblast cells (GM00637). The aziridinyl substituent is required for hypersensitive killing of Fanconi anaemia (FA) cells (PD20i) deficient in FANCD2. Despite lacking quinone functionality, 4,7-dimethoxy-N-[(aziridin-2-yl)methyl]benzimidazole also induces hypersensitivity from FA cells, similar to their response towards mitomycin C. Expression of FANCD2 (in PD20:RV) corrects FA cell hypersensitivity supporting cellular response via the FANC pathway.

Synthesis and antitumor evaluation of 8-phenylaminopyrimido[4,5-c]isoquinolinequinones

A series of 8-phenylaminopyrimido[4,5-c]isoquinoline-7,10-quinone derivatives were prepared by regioselective amination reaction of pyrimido[4,5-c]isoquinoline-7,10-quinones with arylamines in the presence of a Lewis acid catalyst. Preliminary evaluation of the members of the series against cancer cell lines and assays of activation of their cytotoxic activity on K562 cells with ascorbic acid are reported.

Studies on quinones. Part 45: novel 7-aminoisoquinoline-5,8-quinone derivatives with antitumor properties on cancer cell lines

A variety of 7-aminoisoquinoline-5,8-quinone derivatives were prepared from 2,5-dihydroxyacetophenone, methyl aminocrotonate, and the corresponding amines, through a highly efficient three-step sequence. The members of this series were tested on normal human fibroblasts and on a panel of three human cancer cell lines and their redox properties were determined by cyclic voltammetry in acetonitrile. Both the cytotoxicity and antitumor activity of 7-phenylaminoisoquinoline-5,8-quinone derivatives showed correlation with their half wave potentials and lipophilicities.

First synthesis of N-[(aziridin-2-yl)methyl]benzimidazolequinone and analysis of toxicity towards normal and Fanconi anemia cells

A diazole is N-substituted with 1-trityl-2-methylaziridine and demethylated and oxidised with NBS under acidic conditions to give a benzimidazolequinone; this novel anti-tumour agent is marginally more cytotoxic than mitomycin C (MMC) towards the normal human fibroblast cell line GM00637, while the MMC-hypersensitive human Fanconi anaemia (FA) cell line, PD20i, lacking the FANCD2 protein, is also hypersensitive to the benzimidazolequinone, with expression of FANCD2 protein decreasing sensitivity to both MMC and the benzimidazolequinone.