Design, synthesis and biological evaluation of type-II VEGFR-2 inhibitors based on quinoxaline scaffold

Metal- and photocatalyst-free approach to visible-light-induced acylation of quinoxalinones

A transition-metal- and photocatalyst-free photochemical reaction was successfully developed for the direct acylation of quinoxalin-2(1H)-ones, which was enabled by the formation of electron donor-acceptor (EDA) complexes. The use of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the electron donor allows efficient and operationally simple access to a series of C3-aroylated and acylated quinoxalin-2(1H)-ones with moderate to good yields.

The first-in-class pyrazole-based dual InhA-VEGFR inhibitors towards integrated antitubercular host-directed therapy

Several facets of the host response to tuberculosis have been tapped for clinical investigation, especially targeting angiogenesis mediated by VEGF signaling from infected macrophages. Herein, we rationalized combining the antiangiogenic effects of VEGFR-2 blockade with direct antitubercular InhA inhibition in single hybrid dual inhibitors as advantageous alternatives to the multidrug regimens. Inspired by expanded triclosans, the ether ligation of triclosan was replaced by rationalized linkers to assemble the VEGFR-2 inhibitors thematic scaffold. Accordingly, new series of 3-(p-chlorophenyl)-1-phenylpyrazole derivatives tethered to substituted ureas and their isosteres were synthesized, evaluated against Mycobacterium tuberculosis virulent cell line H37Rv, and assessed for their InhA inhibitory activities. The urea derivatives 8d and 8g exhibited the most promising antitubercular activity (MIC = 6.25 µg/mL) surpassing triclosan (MIC = 20 µg/mL) with potential InhA inhibition, thus identified as the study hits. Interestingly, both compounds inhibited VEGFR-2 at nanomolar IC50 (15.27 and 24.12 nM, respectively). Docking and molecular dynamics simulations presumed that 8d and 8g could bind to their molecular targets InhA and VEGFR-2 posing essential stable interactions shared by the reference inhibitors triclosan and sorafenib. Finally, practical LogP, Lipinski's parameters and in silico ADMET calculations highlighted their drug-likeness as novel leads in the arsenal against TB.

Visible-light-mediated direct C3 alkylation of quinoxalin-2(1H)-ones using alkanes

Due to the high C-H bond dissociation energy of alkanes, the utilization of alkanes as alkyl radical precursors for C-H functionalization of heteroarenes is synthetically captivating but practically challenging, especially under metal- and photocatalyst-free conditions. We report herein a mild and practical visible-light-mediated method for C-H alkylation of quinoxalin-2(1H)-ones using trifluoroacetic acid as a hydrogen atom transfer reagent and air as an oxidant. This mild protocol was performed under metal- and photocatalyst-free circumstances and presented good functional-group tolerance as well as a broad substrate scope.

Role of heterocycles in inhibition of VEGFR-2 - a recent update (2019-2022)

The literature reveals that oncogenic protein kinase inhibition has been proved to be a successful anticancer approach. The vascular endothelial growth factor receptor (VEGFR) kinase plays an important role in angiogenesis and metastasis. VEGFR-2 has an upper hand in the angiogenesis process. Vascular endothelial growth factor activates VEGFR-2 which initiates tumor angiogenesis. In addition, VEGFRs are associated with numerous other diseases. Hence, inhibition of VEGFRs is an attractive approach for cancer treatment. In view of this, researchers designed and discovered small molecular heterocycle-based VEGFR-2 inhibitors and some of them have been approved by the Food and Drug Administration (FDA). However, these VEGFR-2 inhibitors pose adverse side effects such as cardiovascular problems, diarrhea, and renal function impairment. Research indicates that combination of certain pharmacophores exhibits excellent VEGFR inhibitory activity. In particular, combination of heterocycles paved the way to efficient VEGFR inhibitors. In this review, the research focusing on VEGFR inhibitory activity has been discussed along with the structure-activity relationship. In addition to emphasizing the most potent molecule among the set of designed molecules, structural features responsible for such an activity are described. This review may aid in designing potent VEGFR inhibitors.

Challenging the anticolorectal cancer capacity of quinoxaline-based scaffold via triazole ligation unveiled new efficient dual VEGFR-2/MAO-B inhibitors

Monoamine oxidases (MAOs) and vascular endothelial growth factor receptor-2 (VEGFR-2) are promoters of colorectal cancer (CRC) and central signaling nodes in epithelial-mesenchymal transition (EMT) induced by activating hypoxia-inducible factors (HIFs). Herein, a novel series of rationally designed triazole-tethered quinoxalines were synthesized and evaluated against HCT-116 CRC cells. The tailored scaffolds combine the pharmacophoric themes of both VEGFR-2 inhibitors and MAO inhibitors. All the synthesized derivatives were screened utilizing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay for their possible cytotoxic effects on normal human colonocytes, then evaluated for their anticancer activities against HCT-116 cells overexpressing MAOs. The hit derivatives 11 and 14 exhibited IC50 = 18.04 and 7.850 µM, respectively, against HCT-116cells within their EC100 doses on normal human colonocytes. Wound healing assay revealed their efficient CRC antimetastatic activities recording HCT-116 cell migration inhibition exceeding 75 %. In vitro enzymatic assays demonstrated that both 11 and 14 efficiently inhibited VEGFR-2 (IC50 = 88.79 and 9.910 nM), MAO-A (IC50 = 0.763 and 629.1 nM) and MAO-B (IC50 = 0.488 and 209.6 nM) with observed MAO-B over MAO-A selectivity (SI = 1.546 and 3.001), respectively. Enzyme kinetics studies were performed for both compounds to identify their mode of MAO-B inhibition. Furthermore, qRT-PCR analysis showed that the hits efficiently downregulated HIF-1α in HCT-116cells by 3.420 and 16.96 folds relative to untreated cells. Docking studies simulated their possible binding modes within the active sites of VEGFR-2 and MAO-B to highlight their essential structural determinants of activities. Finally, they recorded in silico drug-like absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles as well as ligand efficiency metrics.

New nicotinamide derivatives as potential anticancer agents targeting VEGFR-2: design, synthesis, in vitro, and in silico studies

Herin, new nicotinamide candidates were designed and synthesized as VEGFR-2 inhibitors. In vitro antiproliferative activities were assessed against MCF-7, HepG-2 and HCT-116 cancer cell lines. The top cytotoxic members 15a, 15b, 16, 18a, and 18b were estimated against their selected target (VEGFR-2). Further mechanistic tests were studied for the most potent cytotoxic candidate 18a, these studies revealed the ability of compound 18a to hinder the progression of HCT-116 cells at S and Pre-G1phases besides boosting early and late apoptosis. Also compound 18a was found to significantly decrease the levels immunomodulatory proteins TNF-α and IL-6 while showing a four-fold rise in an apoptotic marker caspase-3 when compared to control cells. The therapeutic index of the designed derivatives was evaluated by computational ADMET and toxicity calculations as well as their potentiality to occupy the VEGFR-2 active site was signposted by molecular docking assessments. Finally, molecular dynamic simulation studies of compound 18a-VEGFR-2 complex indicated the high steadiness of compound 18a in the VEGFR-2 active site. This study presents compound 18a as a lead candidate that can be optimized to get a strong VEGFR-2 inhibitor.Communicated by Ramaswamy H. Sarma.

Aerobic oxidative C-H phosphorylation of quinoxalines under catalyst-free conditions

We herein report a direct and efficient protocol for phosphorylation of quinoxalines, which employs aerobic oxygen as the green oxidant under catalyst-free conditions. This methodology represents one of the most environmentally friendly and easily handled protocols, providing a series of phosphorylated quinoxalines in good to excellent yields. Control experiments clearly indicated that the reaction followed a dearomatization-rearomatization strategy.

Anti-cancer and immunomodulatory evaluation of new nicotinamide derivatives as potential VEGFR-2 inhibitors and apoptosis inducers: in vitro and in silico studies

New nicotinamide derivatives 6, 7, 10, and 11 were designed and synthesised based on the essential features of the VEGFR-2 inhibitors. Compound 10 revealed the highest anti-proliferative activities with IC₅₀ values of 15.4 and 9.8 µM against HCT-116 and HepG2, respectively compared to sorafenib (IC₅₀ = 9.30 and 7.40 µM). Compound 7 owned promising cytotoxic activities with IC₅₀ values of 15.7 and 15.5 µM against the same cell lines, respectively. Subsequently, the VEGFR-2 inhibitory activities were assessed for the titled compounds to exhibit VEGFR-2 inhibition with sub-micromolar IC₅₀ values. Moreover, compound 7 induced the cell cycle cessation at the cycle at %G2-M and G0-G1phases, and induced apoptosis in the HCT-116. Compounds 7 and 10 reduced the levels of TNF-α by 81.6 and 84.5% as well as IL-6 by 88.4 and 60.9%, respectively, compared to dexamethasone (82.4 and 93.1%). In silico docking, molecular dynamics simulations, ADMET, and toxicity studies were carried out.

Design, Synthesis, In Silico and In Vitro Studies of New Immunomodulatory Anticancer Nicotinamide Derivatives Targeting VEGFR-2

VEGFR-2, the subtype receptor tyrosine kinase (RTK) responsible for angiogenesis, is expressed in various cancer cells. Thus, VEGFER-2 inhibition is an efficient approach for the discovery of new anticancer agents. Accordingly, a new set of nicotinamide derivatives were designed and synthesized to be VEGFR-2 inhibitors. The chemical structures were confirmed using IR, 1H-NMR, and 13C-NMR spectroscopy. The obtained compounds were examined for their anti-proliferative activities against the human cancer cell lines (HCT-116 and HepG2). VEGFR-2 inhibitory activities were determined for the titled compounds. Compound 8 exhibited the strongest anti-proliferative activities with IC50 values of 5.4 and 7.1 µM against HCT-116 and HepG2, respectively. Interestingly, compound 8 was the most potent VEGFR-2 inhibitor with an IC50 value of 77.02 nM (compare to sorafenib: IC50 = 53.65 nM). Treatment of HCT-116 cells with compound 8 produced arrest of the cell cycle at the G0–G1 phase and a total apoptosis increase from 3.05 to 19.82%—6.5-fold in comparison to the negative control. In addition, compound 8 caused significant increases in the expression levels of caspase-8 (9.4-fold) and Bax (9.2-fold), and a significant decrease in the Bcl-2 expression level (3-fold). The effects of compound 8 on the levels of the immunomodulatory proteins (TNF-α and IL-6) were examined. There was a marked decrease in the level of TNF-α (92.37%) compared to the control (82.47%) and a non-significant reduction in the level of IL-6. In silico docking, molecular dynamics simulations, and MM-PBSA studies revealed the high affinity, the correct binding, and the optimum dynamics of compound 8 inside the active site of VEGFR-2. Finally, in silico ADMET and toxicity studies indicated acceptable values of drug-likeness. In conclusion, compound 8 has emerged as a promising anti-proliferative agent targeting VEGFR-2 with significant apoptotic and immunomodulatory effects.

Enhancing the Anticancer Potential of Targeting Tumor-Associated Metalloenzymes via VEGFR Inhibition by New Triazolo[4,3-a]pyrimidinone Acyclo C-Nucleosides Multitarget Agents

The role of metalloenzymes in tumor progression had broadened their application in cancer therapy. Of these, MMPs and CAs are validated druggable targets that share some pivotal signaling pathways. The majority of MMPs or CAs inhibitors are designed as single-target agents. Despite their transient efficacy, these agents are often susceptible to resistance. This set the stage to introduce dual inhibitors of correlated MMPs and CAs. The next step is expected to target the common vital signaling nodes as well. In this regard, VEGFR-2 is central to various tumorigenesis events involving both families, especially MMP-2 and CA II. Herein, we report simultaneous inhibition of MMP-2, CA II, and VEGFR-2 via rationally designed hybrid 1,2,4-triazolo[4,3-a]pyrimidinone acyclo C-nucleosides. The promising derivatives were nanomolar inhibitors of VEGFR-2 (8; IC₅₀ = 5.89 nM, 9; IC₅₀ = 10.52 nM) and MMP-2 (8; IC₅₀ = 17.44 nM, 9; IC₅₀ = 30.93 nM) and submicromolar inhibitors of CA II (8; IC₅₀ = 0.21 µM, 9; IC₅₀ = 0.36 µM). Docking studies predicted their binding modes into the enzyme active sites and the structural determinants of activity regarding substitution and regioselectivity. MTT assay demonstrated that both compounds were 12 folds safer than doxorubicin with superior anticancer activities against three human cancers recording single-digit nanomolar IC₅₀, thus echoing their enzymatic activities. Up to our knowledge, this study introduces the first in class triazolopyrimidinone acyclo C-nucleosides VEGFR-2/MMP-2/CA II inhibitors that deserve further investigation.

New Series of VEGFR-2 Inhibitors and Apoptosis Enhancers: Design, Synthesis and Biological Evaluation

Background

Cancer is still a major world health threat, causing a high rate of mortality. VEGFR-2 inhibitor anticancer agents are of great significance. However, they showed some serious side effects.

Purpose

To discover new effective and safer anticancer agents, a new series of piperazinylquinoxaline-based derivatives was designed and synthesized on the basis of the pharmacophoric features of VEGFR-2 inhibitor drugs.

Methods

The new candidates were evaluated against A549 lung cancer cells, HepG-2 hepatoma cells, Caco-2 colon cancer cells, MDA breast cancer cells, and VEGFR-2 kinase. Moreover, cell cycle kinetics and apoptosis rates were studied in HepG-2 cells treated with compound 11, which was the most promising candidate.

Results

The new derivatives revealed better antitumor results (IC₅₀ from 6.48 to 38.58 µM) against the aforementioned cancer cell lines than sorafenib. Also, the new candidates showed VEGFR-2 inhibition with IC₅₀ values ranging from 0.19 to 0.60 µM compared to 0.08 µM for sorafenib. Compound 11, meanwhile, showed IC₅₀ values equal to 10.61, 9.52, 12.45, 11.52, and 0.19 µM against the cancer cell lines and VEGFR-2, respectively. Moreover, compound 11 raised the apoptosis rate in HepG-2 cells from 5% to 44% and caused 4, 2.3, and 3-fold increases in BAX/Bcl-2 ratio, caspase-3 level, and P53 expression, respectively, compared to control untreated cells. Finally, the new derivatives displayed the correct binding mode into VEGFR-2 kinase pocket, giving interactions with the essential residues.

Conclusion

This work suggests that compound 11 is a very significant anticancer candidate, and piperazinylquinoxaline is an important scaffold in the development of new potential effective and safer VEGFR-2 inhibitor agents.

Functionalized quinoxalinones as privileged structures with broad-ranging pharmacological activities

Quinoxalinones are a class of heterocyclic compounds which attract extensive attention owing to their potential in the field of organic synthesis and medicinal chemistry. During the past few decades, many new synthetic strategies toward the functionalization of quinoxalinone based scaffolds have been witnessed. Regrettably, there are only a few reports on the pharmacological activities of quinoxalinone scaffolds from a medicinal chemistry perspective. Therefore, herein we intend to outline the applications of multifunctional quinoxalinones as privileged structures possessing various biological activities, including anticancer, neuroprotective, antibacterial, antiviral, antiparasitic, anti-inflammatory, antiallergic, anti-cardiovascular, anti-diabetes, antioxidation, etc. We hope that this review will facilitate the development of quinoxalinone derivatives in medicinal chemistry.

Synthesis of novel antibacterial and antifungal quinoxaline derivatives

A series of quinoxaline derivatives were designed, synthesized and evaluated as antimicrobial agents against plant pathogenic bacteria and fungi. Some of these compounds exhibited significant antibacterial and antifungal activities in vitro. Compound 5k displayed good antibacterial activity against Acidovorax citrulli (Ac). Compounds 5j and 5t exhibited the most potent anti-RS (Rhizoctonia solani) activity, with the corresponding EC₅₀ values of 8.54 and 12.01 μg mL⁻¹, respectively, which are superior to that of the commercial azoxystrobin (26.17 μg mL⁻¹). Further, the scanning electron microscopy results proved that compound 5j had certain effects on the cell morphology of RS. Moreover, an in vivo bioassay also demonstrated that the anti-RS activity of compound 5j could effectively control rice sheath blight. These results indicate that quinoxaline derivatives could be promising agricultural bactericides and fungicides.

Structure of some commercial agents.

Metal-free three-component cyanoalkylation of quinoxalin-2(1H)-ones with vinylarenes and azobis(alkylcarbonitrile)s

A K2S2O8-mediated C3 cyanoalkylation of quinoxalin-2(1H)-ones via a three-component radical cascade reaction with vinylarenes and azobis(alkylcarbonitrile)s has been achieved.

Targeting VEGFR-2 by new quinoxaline derivatives: Design, synthesis, antiproliferative assay, apoptosis induction, and in silico studies

Twelve new triazolo[4,3-a]quinoxaline-based compounds are reported as anticancer agents with potential effects against vascular endothelial growth factor receptor-2 (VEGFR-2), using sorafenib as a reference molecule. With sorafenib as the positive control, the antiproliferative effects of the synthesized compounds against MCF-7 and HepG2 cells, as well as their VEGFR-2-inhibitory activities, were assessed. The most powerful VEGFR-2 inhibitor was compound 14a, which had an IC₅₀ value of 3.2 nM, which is very close to that of sorafenib (IC₅₀  = 3.12 nM). Furthermore, compounds 14c and 15d showed potential inhibitory activity against VEGFR-2, with IC₅₀ values of 4.8 and 5.4 nM, respectively. Compound 14a caused apoptosis in HepG2 cells and stopped the cell cycle at the G2/M phase. In HepG2 cells, it also increased the levels of the proteases caspase-3 and caspase-9, as well as the Bax/Bcl-2 ratio. In silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) and toxicity experiments revealed that the synthesized agents had acceptable drug-likeness.

Design, synthesis, docking, ADMET studies, and anticancer evaluation of new 3-methylquinoxaline derivatives as VEGFR-2 inhibitors and apoptosis inducers

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a critical role in cancer angiogenesis. Inhibition of VEGFR-2 activity proved effective suppression of tumour propagation. Accordingly, two series of new 3-methylquinoxaline derivatives have been designed and synthesised as VEGFR-2 inhibitors. The synthesised derivatives were evaluated in vitro for their cytotoxic activities against MCF-7and HepG2 cell lines. In addition, the VEGFR-2 inhibitory activities of the target compounds were estimated to indicate the potential mechanism of their cytotoxicity. To a great extent, the results of VEGFR-2 inhibition were highly correlated with that of cytotoxicity. Compound 27a was the most potent VEGFR-2 inhibitor with IC50 of 3.2 nM very close to positive control sorafenib (IC50 = 3.12 nM). Such compound exhibited a strong cytotoxic effect against MCF-7 and HepG2, respectively with IC50 of 7.7 and 4.5 µM in comparison to sorafenib (IC50 = 3.51 and 2.17 µM). In addition, compounds 28, 30f, 30i, and 31b exhibited excellent VEGFR-2 inhibition activities (IC50 range from 4.2 to 6.1 nM) with promising cytotoxic activity. Cell cycle progression and apoptosis induction were investigated for the most active member 27a. Also, the effect of 27a on the level of caspase-3, caspase-9, and BAX/Bcl-2 ratio was determined. Molecular docking studies were implemented to interpret the binding mode of the target compounds with the VEGFR-2 pocket. Furthermore, toxicity and ADMET calculations were performed for the synthesised compounds to study their pharmacokinetic profiles.

Synthesis, in vitro anticancer activity and in silico studies of certain isoxazole-based carboxamides, ureates, and hydrazones as potential inhibitors of VEGFR2

The ensuing research presents the results of in vitro anticancer activity of novel 28 compounds of isoxazole-based carboxamides 3(a-d); ureates 4(a-g), 5, 6, 7a,b, 8; and hydrazones 9(a-f), 10(a-d), 11a,b as potential inhibitors of VEGFR2. The carboxamides and ureates were synthesized by converting 5-(aryl)-isoxzaole-3-carbohydrazides 1a,b to the corresponding carbonylazides 2a,b followed by treatment with the appropriate amines. The hydrazones were directly obtained through condensation of the carbohydrazide 1a,b with aldehydes and/or ketones. The structures of the target compounds were confirmed by elemental and spectral analyses. A preliminary in vitro anticancer screening of solutions (10^-5M) on 60 cancer cell lines (NCI, USA) revealed that the carboxamide 3c is the most promising growth inhibitor. Explicitly, 3c showed potent anticancer activity at 10µ M against leukemia (HL-60(TB), K-562 and MOLT-4), colon cancer (KM12) and melanoma (LOX IMVI) cell lines with %GI range = 70.79-92.21. Evaluation of growth inhibitory activity of the synthesized compounds against hepatocellular carcinoma (HepG2), that overexpresses VEGFR2, showed superior activity of compounds 8, 10a and 10c with IC₅₀ in sub micromolar concentrations of 0.84, 0.79 and 0.69 μM, respectively, which is better than that of the reference drug, Sorafenib (IC₅₀ = 3.99 µM). Moreover, these compounds displayed high selective cytotoxicity for HepG2 cancer cells over the nontumorigenic THLE2 liver cells (SI range = 26.37-38.60) which reflect their safety. The results of VEGFR2 kinase inhibition assay demonstrate that, compounds 8 and 10a are the most active inhibitors with IC₅₀ = 25.7 and 28.2 nM, respectively, (Sorafenib IC₅₀ = 28.1 nM). Molecular docking of the synthesized derivatives to VEGFR2 (PDB: 3WZE) showed similar binding modes to that of the co-crystallized ligand, sorafenib. Moreover, the results of computational assessment of ADME and drug-likeness characteristics inspire further investigations of the new isoxazole-based derivatives to afford more potent, safe and orally active VEGFR2 inhibitors as potential anticancer drug candidates.

Design, synthesis and molecular docking of new [1,2,4] triazolo[4,3-a]quinoxaline derivatives as anticancer agents targeting VEGFR-2 kinase

Vascular endothelial growth factor receptor-2 (VEGFR-2) is critically involved in cancer angiogenesis. Blocking of VEGFR-2 signaling pathway proved effective suppression of tumor growth. Accordingly, two series of new triazoloquinoxaline-based derivatives were designed and synthesized as VEGFR-2 inhibitors. All in vitro cytotoxic activities of the synthesized compounds were evaluated against two human cancer cell lines (MCF-7 and HepG2). To confirm the potential mechanism of cytotoxicity, enzymatic assays against VEGFR-2 were estimated for all the target compounds. The results of VEGFR-2 inhibitory activity and cytotoxicity were in high correlation. Compound 22a exhibited the highest cytotoxic effect with IC₅₀ values of 6.2 and 4.9 μM against MCF-7 and HepG2, respectively, comparing to sorafenib (IC₅₀ = 3.53 and 2.18 μM). Such derivative showed the best VEGFR-2 inhibitory activity with an IC₅₀ value of 3.9 nM, which is very close to that of sorafenib (IC₅₀ = 3.13 nM). Moreover, compounds 22b, 23b, and 23e exhibited strong cytotoxic activity with IC₅₀ values ranging from 11.7 to 15.3 μM. Also, these compounds showed promising VEGFR-2 inhibition with IC₅₀ values of 4.2, 5.7, and 4.7 nM, respectively. In silico docking, ADMET, and toxicity studies were carried out for the synthesized compounds. The results revealed that some compounds have a good binding mode against VEGFR-2 and a high level of drug-likeness.

Discovery of pyridine- sulfonamide hybrids as a new scaffold for the development of potential VEGFR-2 inhibitors and apoptosis inducers

New sulfonamide derivatives have been synthesized and tested as antitumor agents. All newly synthesized compounds were tested in vitro against 60 lines of human cancer cells. Compound VIIb shows broad-spectrum activity with a mean inhibition value of 91.67% against all cell lines. It exhibited potent anticancer activity with GI50 values of 1.06-8.92 μM relative to most of the tested cancer cell lines. Compound VIIb has been tested for enzyme inhibition activity toward vascular endothelial growth factor receptor 2, where VEGFR-2 was potently inhibited at a lower IC50 value of 3.6 μM, compared with sorafenib (IC50 = 4.8 μM). Hybrid VIIb was also able to induce cell cycle disturbance and apoptosis in Renal UO-31 cells, as shown by DNA flow cytometry and Annexin V-FITC/PI assays. It has also revealed lower Bcl-2 protein expression anti-apoptotic levels and higher BAX, p53, and caspases 3 expression levels.

New quinoxaline derivatives as VEGFR-2 inhibitors with anticancer and apoptotic activity: Design, molecular modeling, and synthesis

New series of [1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one and [1,2,4]triazolo[4,3-a]quinoxaline derivatives have been designed, synthesized, and biologically assessed for their anti-proliferative activities against two selected tumor cell lines MCF-7 and HepG2. Comparing to sorafenib (IC₅₀ = 2.17 ± 0.13 and 3.51 ± 0.21 µM against MCF-7 and HepG2, respectively), compound 25d, 25e, 25i, and 27e exhibited the highest activities against the examined cell lines with IC₅₀ values extending from 4.1 ± 0.4 to 11.7 ± 1.1 µM. Furthermore, VEGFR-2 inhibitory activities were assessed for all the synthesized compounds as potential mechanisms for their anti-proliferative activities. Compounds 25d, 25e, 25i, and 27e displayed prominent inhibitory efficiency versus VEGFR-2 kinase with IC₅₀ value ranging from 3.4 ± 0.3 to 6.8 ± 0.5 nM. Fascinatingly, the results of VEGFR-2 inhibitory assays were matched with that of the cytotoxicity data, where the most potent anti-proliferative derivatives exhibited promising VEGFR-2 inhibitory activities. Further studies displayed the ability of compound 25d to induce apoptosis in HepG2 cells and can arrest the growth of such cells at the G2/M phase. Also, compound 25d produced a significant increase in the level of BAX/Bcl-2 ratio (3.8-fold), caspase- 3 (1.8-fold), and caspase-9 (1.9-fold) compared to the control cells. Molecular docking studies were carried out to investigate the possible binding interaction inside the active site of the VEGFR-2.

Design, synthesis, molecular docking, in silico ADMET profile and anticancer evaluations of sulfonamide endowed with hydrazone-coupled derivatives as VEGFR-2 inhibitors

A new series of sulfonamide endowed with hydrazone coupled to dimethyl and/or diethyl malonates were prepared. Various sulfa drugs were diazotized and followed by coupling with active methylene of dimethyl and/or diethyl malonate to afford the new intermediates hydrazones 3_a-c and 4_a-c. The reactivity of hydrazone derivatives towards hydrazines was investigated. Thus, a novel series of 3,5-dioxopyrazolidine7_a-cwere obtained by treatment with hydrazine hydrate. When hydrazones were allowed to react with phenyl hydrazine, the alkyl 2-((4-(N-(substituted)sulfamoyl)phenyl)diazenyl)-3-oxo-3-(2-phenylhydrazinyl)propanoateswere obtained 8_a-c and/or 10_a-c. Their anticancer activities were evaluated against HepG2, HCT-116 and MCF-7. HepG2 was the most sensitive one. In particular, compounds 7_c, 7_b and 10_c were found to be the most potent derivatives with IC₅₀ = 6.43 ± 0.5, 9.66 ± 0.8, 10.57 ± 0.9 µM, 8.65 ± 0.7, 7.49 ± 0.6, 14.29 ± 1.3 µM and 8.97 ± 0.7, 10.13 ± 0.9, 13.82 ± 1.1 µM respectively. Sorafenib and doxorubicin were used as reference drugs. The most potent derivatives 7_a, 7_b, 7_c, 8_c and 10_c were tested for their cytotoxicity against normal VERO cell lines. Compounds 7_a, 7_b, 7_c, 8_c and 10_c are respectively, 2.41, 4.85, 4.08, 3.23 and 5.89 fold times more toxic in HCT116 than in VERO normal cells. Moreover, the most active anti-proliferative derivatives 7_a, 7_b, 7_c, 8_c and 10_c were subjected to further biological study to evaluate their inhibitory potentials against VEGFR-2. The tested compounds displayed high to good inhibitory activity with IC₅₀ values ranging from 0.14 ± 0.02 to 0.23 ± 0.03 µM. Among them, compounds 7_c, 7_b and 10_c were found to be the most potent derivative that inhibited VEGFR-2 at IC₅₀ values of 0.14 ± 0.02, 0.15 ± 0.02 and 0.15 ± 0.02 µM respectively. sorafenib was used as reference drug. Furthermore, ADMET profile was evaluated for the four most active compounds in comparison to doxorubicin as a reference drug. The data obtained from docking studies were highly correlated with that obtained from the biological screening.

A visible-light photoredox-catalyzed four-component reaction for the construction of sulfone-containing quinoxalin-2(1H)-ones

A visible-light photoredox-catalyzed four component reaction of quinoxalin-2(1H)-ones, alkenes, aryldiazonium, and sodium metabisulfite leading to sulfone-containing quinoxalin-2(1H)-ones has been developed.

Design, synthesis and biological evaluation of novel 4-phenoxypyridine based 3-oxo-3,4-dihydroquinoxaline-2-carboxamide derivatives as potential c-Met kinase inhibitors

Blocking c-Met kinase activity by small-molecule inhibitors has been identified as a promising approach for the treatment of cancers. Herein, we described the design, synthesis, and biological evaluation of a series of 4-phenoxypyridine-based 3-oxo-3,4-dihydroquinoxaline derivatives as c-Met kinase inhibitors. Inhibitory activitives against c-Met kinase evaluation indicated that most of compounds showed excellent c-Met kinase activity in vitro, and IC₅₀ values of ten compounds (23a, 23e, 23f, 23l, 23r, 23s, 23v, 23w, 23x and 23y) were less than 10.00 nM. Notably, three of them (23v, 23w and 23y) showed remarkable potency with IC₅₀ values of 2.31 nM, 1.91 nM and 2.44 nM, respectively, and thus they were more potent than positive control drug foretinib (c-Met, IC₅₀ = 2.53 nM). Cytotoxic evaluation indicated the most promising compound 23w showed remarkable cytotoxicity against A549, H460 and HT-29 cell lines with IC₅₀ values of 1.57 μM, 0.94 μM and 0.65 μM, respectively. Furthermore, the acridine orange/ethidium bromide (AO/EB) staining, cell apoptosis assays by flow cytometry, wound-healing assays and transwell migration assays on HT-29 and/or A549 cells of 23w were performed. Especially compound 23w, which displayed potent antitumor, apoptosis induction and antimetastatic activity, could be used as a promising lead for further development. Meanwhile, their preliminary structure-activity relationships (SARs) were also discussed.

Visible-light-promoted acridine red catalyzed aerobic oxidative decarboxylative acylation of α-oxo-carboxylic acids with quinoxalin-2(1H)-ones

Visible-light-mediated procedure has been developed for the synthesis of 3-acyl quinoxalin-2(1H)-ones through acridine red catalyzed decarboxylative acylation of α-oxo-carboxylic acids with quinoxalin-2(1H)-ones.

Electrochemical decarboxylative C3 alkylation of quinoxalin-2(1H)-ones with N-hydroxyphthalimide esters

Electrochemical decarboxylative C3 alkylation of a wide range of quinoxalin-2(1H)-ones under metal- and additive-free conditions was reported.

Evolution in medicinal chemistry of sorafenib derivatives for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Traditional chemotherapy drugs are hard to reach a satisfactory therapeutic effect since advanced HCC is highly chemo-resistant. Sorafenib is an oral multikinase inhibitor that can suppress tumor cell proliferation, angiogenesis and induce cancer cell apoptosis. However, the poor solubility, rapid metabolism and low bioavailability of sorafenib greatly restricted its further clinical application. During the past decade, numerous sorafenib derivatives have been designed and synthesized to overcome its disadvantages and improve its clinical performance. This article focuses on the therapeutic effects and mechanisms of various sorafenib derivatives with modifications on the N-methylpicolinamide group, urea group, central aromatic ring or others. More importantly, this review summarizes the current status of the structure-activity relationship (SAR) of reported sorafenib derivatives, which can provide some detailed information of future directions for further structural modifications of sorafenib to discovery new anti-tumor drugs with improved clinical performance.

Design and Synthesis of New Quinoxaline Derivatives as Anticancer Agents and Apoptotic Inducers

The quinoxaline scaffold is a promising platform for the discovery of active chemotherapeutic agents. Three series of quinoxaline derivatives were synthesized and biologically evaluated against three tumor cell lines (HCT116 human colon carcinoma, HepG2, liver hepatocellular carcinoma and MCF-7, human breast adenocarcinoma cell line), in addition to VEGFR-2 enzyme inhibition activity. Compounds VIId, VIIIa, VIIIc, VIIIe and XVa exhibited promising activity against the tested cell lines and weak activity against VEGFR-2. Compound VIIIc induced a significant disruption in the cell cycle profile and cell cycle arrest at the G2/M phase boundary. In further assays, the cytotoxic effect of the highly active compounds was determined using a normal Caucasian fibroblast-like fetal lung cell line (WI-38). Compound VIIIc could be considered as a lead compound that merits further optimization and development as an anti-cancer and an apoptotic inducing candidate against the HCT116 cell line.

Visible-light-promoted direct C–H/S–H cross-coupling of quinoxalin-2(1H)-ones with thiols leading to 3-sulfenylated quinoxalin-2(1H)-ones in air

A new and efficient visible-light-mediated strategy has been developed for the synthesis of 3-sulfenylated quinoxalin-2(1H)-ones via rhodamine B catalyzed C–H/S–H cross-coupling of quinoxalin-2(1H)-ones with thiols in air at room temperature.

Synthesis, anticancer activity, toxicity evaluation and molecular docking studies of novel phenylaminopyrimidine-(thio)urea hybrids as potential kinase inhibitors

Thirty-two novel urea/thiourea compounds as potential kinase inhibitor were designed, synthesized and evaluated for their cytotoxic activity on breast (MCF7), colon (HCT116) and liver (Huh7) cancer cell lines. Compounds 10, 19 and 30 possessing anticancer activity with IC₅₀ values of 0.9, 0.8 and 1.6μM respectively on Huh7 cells were selected for further studies. These hit compounds were tested against liver carcinoma panel. Real time cell electronic sensing assay was used to evaluate the effects of the compounds 10, 19 and 30 on the growth pattern of liver cancer cells. Apoptotic cell death and cell cycle analysis upon treatment of liver carcinoma cells with hit compounds were determined. A significant apoptotic cell death was detected upon treatment of Huh7 and Mahlavu cells with compound 30 after 48 h of treatment. Additionally, compound 10 caused cell cycle arrest at G0/G1 phase. Mutagenicity of hit compounds was evaluated. Assertively, these compounds were not found to be mutagenic on Salmonella typhimurium strains TA98 and TA100. To understand the binding modes of the synthesized compounds, molecular docking studies were performed using the crystal data of VEGFR and Src-kinase enzymes in correlation with anticancer activities.

Antitumoral activity of quinoxaline derivatives: A systematic review

Cancer is a leading cause of death and a major health problem worldwide. While many effective anticancer agents are available, the majority of drugs currently on the market are not specific, raising issues like the common side effects of chemotherapy. However, recent research hold promise for the development of more efficient and safer anticancer drugs. Quinoxaline and its derivatives are becoming recognized as a novel class of chemotherapeutic agents with activity against different tumors. The present review compiles and discusses studies concerning the therapeutic potential of the anticancer activity of quinoxaline derivatives, covering articles published between July 2013 and July 2018.

Design, synthesis and biological evaluation of some novel quinazolinone derivatives as potent apoptotic inducers

Aim: Novel quinazolinone and triazinoquinazolinone derivatives were designed and synthesized as apoptotic inducers. Methodology/results: Most of the synthesized compounds showed excellent antiproliferative activity against MCF-7 and HCT-116 cell lines, respectively. Compounds 7a, 8a, 8d, 14a and 14d were superior to doxorubicin as activators of caspases 3, 8 and 9 in HCT-116 cell line. The most potent caspase inducers, 8d and 14a showed cell cycle arrest mainly in G1 and S phase, respectively and increased the levels of p53, Bax and the Bax/Bcl-2 ratio compared with doxorubicin in HCT-116 cells with excellent selectivity against CCD-18Co human colon normal cell line. Conclusion: The synthesized compounds can be considered as potent apoptotic inducers interfering with extrinsic and intrinsic apoptotic pathways.

Synthesis and cytotoxic evaluation of some novel quinoxalinedione diarylamide sorafenib analogues

A series of novel sorafenib analogues containing a quinoxalinedione ring and amide linker were synthesized. A total of 9 novel compounds in 6 synthetic steps were synthesized. Briefly, the amino group of p-aminophenol was first protected which then followed by O-arylation with 5-chloro-2-nitroaniline to provide compound d. Reduction of the nitro group of compound d and cyclization of the diamine group of compound e with oxalic acid afforded compound f which on deacetylation yeilded compound g. Then compound g was reacted with different acyl halides to afford the target compounds 1h-1p. Chemical structures of synthesized compounds were confirmed by 1H NMR and FT-IR analysis. All compounds were evaluated at 1, 10, 50 and 100 μM concentrations for their cytotoxicity against HeLa and MCF-7 cancer cell lines. Some of the compounds showed good cytotoxic activity, especially compounds 1i and 1k-1n with the IC50 values of 19, 16, 22, 18, and 16 μM against MCF-7 cell line and 20, 18, 25, 20, and 18 μM against HeLa cell line, respectively.

Quinoxaline-Based Scaffolds Targeting Tyrosine Kinases and Their Potential Anticancer Activity

Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.