Design and synthesis of new tetrazolyl- and carboxy-biphenylylmethyl-quinazolin-4-one derivatives as angiotensin II AT1 receptor antagonists

Recent Advances in Metal-Catalyzed Approaches for the Synthesis of Quinazoline Derivatives

Quinazolines are an important class of heterocyclic compounds that have proven their significance, especially in the field of organic synthesis and medicinal chemistry because of their wide range of biological and pharmacological properties. Thus, numerous synthetic methods have been developed for the synthesis of quinazolines and their derivatives. This review article briefly outlines the new synthetic methods for compounds containing the quinazoline scaffold employing transition metal-catalyzed reactions.

Virtual screening approach for the discovery of selective 5α-reductase type II inhibitors for benign prostatic hyperplasia treatment

Background: 5α-Reductase type II (5αR2) inhibition is a promising strategy for benign prostatic hyperplasia treatment. A computational approach including virtual screening, ligand-based 3D pharmacophore modeling, 2D quantitative structure-activity relationship and molecular docking simulations were adopted to develop novel inhibitors. Results: Hits were first filtered via the validated pharmacophore and 2D quantitative structure-activity relationship models. Docking on the recently determined cocrystallized structure of 5αR2 showed three promising hits. Visual inspection results were compared with finasteride ligand and dihydrotestosterone as reference, to explain the role of binding to Glu57 and Tyr91 for 5αR2 selective inhibition. Conclusion: Alignment between Hit 2 and finasteride in the binding pocket showed similar binding modes. The biological activity prediction showed antitumor and androgen targeting activity of the new hits.

Ligand-based drug design of quinazolin-4(3H)-ones as breast cancer inhibitors using QSAR modeling, molecular docking, and pharmacological profiling

BACKGROUND

Breast cancer is the most common tumor among females globally. Its prevalence is growing around the world, and it is alleged to be the leading cause of cancer death. Approved anti-breast cancer drugs display several side effects and resistance during the early treatment stage. Hence, there is a need for the development of more effective and safer drugs. This research was aimed at designing more potent quinazolin-4(3H)-one molecules as breast cancer inhibitors using a ligand-based design approach, studying their modes of interaction with the target enzyme using molecular docking simulation, and predicting their pharmacological properties.

METHODS

The QSAR model was developed using a series of quinazoline-4(3H)-one derivatives by utilizing Material Studio v8.0 software and validated both internally and externally. Applicability domain virtual screening was utilized in selecting the template molecule, which was structurally modified to design more potent molecules. The inhibitive capacities of the design molecules were predicted using the developed model. Furthermore, molecular docking was performed with the EGFR target active site residues, which were obtained from the protein data bank online server (PDB ID: 2ITO) using Molegro Virtual Docker (MVD) software. SwissADME and pkCSM online sites were utilized in predicting the pharmacological properties of the designed molecules.

RESULTS

Four QSAR models were generated, and the first model was selected due to its excellent internal and external statistical parameters as follows: R2 = 0.919, R2adj = 0.898, Q2cv = 0.819, and R2pred = 0.7907. The robustness of the model was also confirmed by the result of the Y-scrambling test performed with cR2p = 0.7049. The selected model was employed to design seven molecules, with compound 4 (pIC50 = 5.18) adopted as the template. All the designed compounds exhibit better activities ranging from pIC50 = 5.43 to 5.91 compared to the template and Doruxybucin (pIC50 = 5.35). The results of molecular docking revealed better binding with the EGFR target compared with the template and Doruxybucin. The designed compounds exhibit encouraging therapeutic applicability, as evidenced by the findings of pharmacological property prediction.

CONCLUSIONS

The designed derivatives could be utilized as novel anti-breast cancer agents.

Visible light-induced cascade N-alkylation/amidation reaction of quinazolin-4(3H)-ones and related N-heterocycles

An efficient and visible light-promoted cascade N-alkylation/amidation of quinazolin-4(3H)-ones with benzyl halides and allyl halides has been described for the first time to provide a convenient access to quinazoline-2,4(1H,3H)-diones. This cascade N-alkylation/amidation reaction shows good functional group tolerance and could also be applied to N-heterocycles such as benzo[d]thiazoles, benzo[d]imidazoles, and quinazolines. Control experiments show that K₂CO₃ plays an important role in this transformation.

Design and synthesis of a new series of hybrids of functionalised N1-[(1H-1,2,3-triazol-4-yl)methyl]quinazoline-2,4-dione with antiviral activity against Respiratory Syncytial Virus

In this study, a series of 48 hybrids of the functionalised 1-[(1H-1,2,3-triazole-4-yl)methyl]quinazoline-2,4-dione 17-22 were synthesised and evaluated for potential antiviral activity. The new hybrids were designed to contain a diethoxyphosphoryl group connected to the triazole moiety via ethylene or propylene linker, and in which the benzyl or benzoyl function is substituted at N3 in the quinazoline-2,4-dione moiety. The Cu(I)-catalyzed Hüisgen dipolar cycloaddition of azidophosphonates 23 and 24 with the respective N¹-propargylquinazoline-2,4-diones 26aa-26ag, 26ba-26bg, 27aa-27ad and 27ba-27bd was applied for the syntheses of the designed compounds. All final hybrids 17-22 and N3-functionalised N¹-propargylquinazoline-2,4-diones 26 and 27 were subsequently evaluated for their antiviral activity toward a broad range of DNA and RNA viruses. Importantly, hybrids 19be-19bg and 20be-20bg showed profound antiviral activities against Respiratory Syncytial Virus (RSV) with EC₅₀ values in the lower micromolar range, with activity against viral strains of both subtypes (RSV A and B). In addition, several compounds also exerted some weak antiviral activity against varicella zoster virus. Finally, 19 ag was the only compound that showed antiviral potency against human cytomegalovirus, although with rather weak inhibitory activity. Notably, none of the tested compounds was cytotoxic toward uninfected cell lines used for the antiviral assays at a concentration up to 100 μM, returning interesting therapeutic indices for respiratory syncytial virus.

Discovery of Novel Quinazoline Derivatives as Potent Antitumor Agents

In this work, we designed and synthesized a novel series of quinazoline derivatives 6–19 and then evaluated their broad-spectrum antitumor activity against MGC-803, MCF-7, PC-9, A549, and H1975, respectively. Most of them demonstrated low micromolar cytotoxicity towards five tested cell lines. In particular, compound 18 exhibited nanomolar level inhibitory activity against MGC-803 cells with an IC₅₀ value of 0.85 μM, indicating approximately a 32-fold selectivity against GES-1 (IC₅₀ = 26.75 μM). Further preclinical evaluation showed that compound 18 remarkably inhibited the migration of MGC-803 cells, induced cell cycle arrest at G2/M, and induced MGC-803 apoptosis, resulting in decreasing the expression of both Bcl-2 and Mcl-1, and up-regulating the expression of both Bax and cleaved PARP. No death or obvious pathological damage was observed in mice by acute toxicity assay. The in vivo antitumor evaluation suggested that compound 18 significantly decreased the average tumor volume and tumor weight without any effect on body weight, which is better than 5-Fu. Therefore, compound 18 can be used as a lead compound for the further development of antitumor drugs in the future.

Copper(I) Catalyzed Decarboxylative Synthesis of Diareno[a,e]cyclooctatetraenes

Diareno[a,e]cyclooctatetraenes find widespread applications as building blocks, ligands, and responsive cores in topologically switchable materials. However, current synthetic methods to these structures suffer from low yields or operational disadvantages. Here, we describe a practical three-step approach to diareno[a,e]cyclooctatetraenes using an efficient copper(I) catalyzed double decarboxylation as the key step. The sequence relies on cheap and abundant reagents, is readily performed on scale, and is amenable also to unsymmetrical derivatives that expand the utility of this intriguing class of structures.

A Concise Synthesis towards Antimalarial Quinazolinedione TCMDC-125133 and Its Anti-Proliferative Activity against MCF-7

Quinazolinedione is one of the most notable pharmacophores in drug discovery due to its broad spectrum of biological activities including antimalarial, anticancer, anti-inflammatory, and others. TCMDC-125133, whose structure features a quinazolinedione core, exhibits promising antimalarial activity and low toxicity as described in the GlaxoSmithKline (GSK) report. Herein, a concise four-step synthesis towards quinazolinedione TCMDC-125133 is described using low cost goods and greener alternatives where possible. All synthesized compounds were characterized using polarimetry, IR, NMR, and mass spectrometry. The in-house synthesized TCMDC-125133 was evaluated for its antimalarial activity against P. falciparum 3D7 and antiproliferative activity against MCF-7 cell line.

A Benzannulation Strategy for Rapid Access to Quinazoline-2,4-diones via Oxidative N-Heterocyclic Carbene Catalysis

N-Heterocyclic carbene-catalyzed formal [4+2] benzannulation of enals with suitably substituted pyrimidine-2,4-diones allowing the mild and facile synthesis of functionalized quinazoline-2,4-diones is presented. This oxidative transformation proceeds via the simultaneous generation of dienolates and α,β-unsaturated acylazoliums and follows a vinylogous Michael/aldol/β-lactonization/decarboxylation/oxidation sequence to afford quinazoline-2,4-diones, including axially chiral ones with suitable substitutions, in an operationally simple procedure. In addition, substituted coumarins as dienolate precursors afforded benzochromen-6-one derivatives.

A Concise and Efficient CuI-catalyzed Synthesis of Diimino Dihydroquinazoline Derivatives from Isocyanides and Guanidines Derivatives Through Intramolecular C-H Activation

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A novel series of diimino dihydroquinazoline derivatives were synthesized from isocyanides and guanidine analogs in quantitative yields by applying an efficient, inexpensive, one-pot copper-catalyzed intramolecular C-H activation reaction under mild conditions. The structures were confirmed on the basis of IR, 1HNMR, 13C NMR, mass spectral and elemental analysis data. The protocol offers advantages like short reaction time, simple workup process, high yields, and an environmentally benign methodology. Interestingly, better results (yield = 82%) were observed in terms of the yield obtained by using a mixture of CuI, Cs2CO3 and acetonitrile as the catalyst, base and solvent, respectively. The data also suggested that compound 5i is produced with the highest yield (87%) from the corresponding diisopropyl carbon diimide, 4-nitroaniline and phenyl isocyanide. Finally, a mechanistic explanation for the reaction promoted by cuprous iodide (CuI) was proposed on the basis of previous investigations and our experimental observations.

Role of the central renin‑angiotensin system in hypertension (Review)

Present in more than one billion adults, hypertension is the most significant modifiable risk factor for mortality resulting from cardiovascular disease. Although its pathogenesis is not yet fully understood, the disruption of the renin-angiotensin system (RAS), consisting of the systemic and brain RAS, has been recognized as one of the primary reasons for several types of hypertension. Therefore, acquiring sound knowledge of the basic science of RAS and the under- lying mechanisms of the signaling pathways associated with RAS may facilitate the discovery of novel therapeutic targets with which to promote the management of patients with cardiovascular and kidney disease. In total, 4 types of angiotensin II receptors have been identified (AT1R-AT4R), of which AT1R plays the most important role in vasoconstriction and has been most extensively studied. It has been found in several regions of the brain, and its distribution is highly associated with that of angiotensin-like immunoreactivity in nerve terminals. The effect of AT1R involves the activation of multiple media and signaling pathways, among which the most important signaling pathways are considered to be AT1R/JAK/STAT and Ras/Raf/MAPK pathways. In addition, the regulation of the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and cyclic AMP response element-binding (CREB) pathways is also closely related to the effect of ATR1. Their mechanisms of action are related to pro-inflammatory and sympathetic excitatory effects. Central AT1R is involved in almost all types of hypertension, including spontaneous hypertension, salt-sensitive hypertension, obesity-induced hypertension, renovascular hypertension, diabetic hypertension, L-NAME-induced hypertension, stress-induced hypertension, angiotensin II-induced hyper- tension and aldosterone-induced hypertension. There are 2 types of central AT1R blockade, acute blockade and chronic blockade. The latter can be achieved by chemical blockade or genetic engineering. The present review article aimed to high- light the prevalence, functions, interactions and modulation means of central AT-1R in an effort to assist in the treatment of several pathological conditions. The identification of angiotensin-derived peptides and the development of AT-2R agonists may provide a wider perspective on RAS, as well as novel therapeutic strategies.

DMAP-Catalyzed One-Pot Synthesis of Quinazoline-2,4-diones from 2-Aminobenzamides and Di-tert-butyl Dicarbonate

The one-pot synthesis of quinazoline-2,4-diones was developed in the presence of 4-dimethylaminopyridine (DMAP) by metal-free catalysis. The commercially available (Boc)₂O acted as a key precursor in the construction of the 2-position carbonyl of quinazolinediones. The p-methoxybenzyl (PMB)-activated heterocyclization could smoothly proceed at room temperature instead of the microwave condition. This strategy is compatible with a variety of substrates with different functional groups. Furthermore, this protocol was utilized to smoothly prepare Zenarestat with a total yield of 70%.

Varlitinib Mediates Its Activity Through Down Regulating MAPK/EGFR Pathway in Oral Cancer

Background:

Oral Squamous Cell Carcinoma (OSCC) is a major sub-type of oral cancer that shares 90% proportion of oral cavity cancers. It is declared as the sixth most frequent cancer among all cancer types throughout the world. Higher morbidity in Asian countries is reported due to frequent use of Smokeless Tobacco (SLT) products besides exposure to other risk factors. Hyperactivation of epidermal growth factor receptors is a molecular event in many solid tumors including oral cancer making them potential therapeutic targets.

Objective:

Current study was designed to explore the effect of varlitinib, a pan-HER inhibitor, on oral cancer cell line. We investigated key regulatory genes in downstream pathway in response to drug treatment. Furthermore, we also examined expression profile of these genes in malignant and healthy oral tissue.

Method:

Gene expression pattern in drug treated and untreated cancer cell line along with OSCC tumor samples (n=45) and adjacent normal tissues was studied using real time PCR.

Results:

In response to varlitinib treatment, significant suppression of oncogenes (IGF1R, MAPK1, SFN and CDK2) was observed. Interestingly, mRNA expression level of CDKN1A and Akt1 was found to be the opposite of what was expected. In case of malignant tissue, over expression of oncogenes (IGF1R, Akt1, MAPK1, SFN and CDK2) with simultaneous down expression of tumor suppressor genes (Tp53 and CDKN1A) was noted. STRING analysis indicated a strong association among differentially expressed genes suggesting their combined role in carcinogenesis.

Conclusion:

In summary, our results indicate that varlitinib can be considered as a potential therapeutic agent in oral cancer due to its antitumor potential.

Recent advances in the pharmacological diversification of quinazoline/quinazolinone hybrids

Due to the pharmacological activities of quinazoline and quinazolinone scaffolds, it has aroused great interest in medicinal chemists for the development of new drugs or drug candidates. The pharmacological activities of quinazoline and its related scaffolds include anti-cancer, anti-microbial, anti-convulsant, and antihyperlipidaemia. Recently, molecular hybridization technology is used for the development of hybrid analogues with improved potency by combining two or more pharmacophores of bioactive scaffolds. The molecular hybridization of various biologically active pharmacophores with quinazoline derivatives resulted in lead compounds with multi-faceted biological activity wherein specific as well as multiple targets were involved. The present review summarizes the advances in lead compounds of quinazoline hybrids and their related heterocycles in medicinal chemistry. Moreover, the review also helps to intensify the drug development process by providing an understanding of the potential role of these hybridized pharmacophoric features in exhibiting various pharmacological activities.

Recent advances in quinazoline/quinazolinone hybrid heterocycles in medicinal chemistry and their pharmacological diversification.

Synthesis of Piperidine Conjugated Dihydroquinazolin-4(1H)-ones and their Antiproliferative Activity, Molecular Docking Studies and DFT Calculations

Background:

Xanthatin, fluoropyrimidine and thienopyrimidine, pyrazolopyrimidine, pyrimidine carboxamides, and SKLB1002 are reported as VEGFR2 tyrosine kinase inhibitors. Recently, many studies related to different heterocycles conjugated with dihydroquinazolinones are known to have very good biological activities. In this study, we are intended to explore the cytotoxic studies of piperidine conjugated dihydroquinazolinones against colorectal/colon cancer cell lines and along with molecular docking studies and DFT calculations.

Methods:

The colorectal/colon cell lines HCT116 and A549 cell lines were treated with these compounds and cytotoxic activities were evaluated by MTT dye uptake method. We performed molecular modelling for compound 3d using the Auto Dock software. The binding of compound 3d with target proteins was studied with the collection of experimentally determined PDB database. Optimized geometry by DFT calculations was performed with B3LYP/6-31G (d) basis set.

Results:

Piperidine-conjugated dihydroquinazolinone analogues displayed anticancer activity. Particularly, the compound 3d with electron-withdrawing substituents on a phenyl ring showed significant cytotoxicity against HCT116 and A549 cell lines. Molecular docking studies proved that the compound 3d has good fitting by forming hydrogen bonds with amino acid residues at the active sites of VEGFR2. The HOMO, LUMO, their energies and UV visible spectrum were predicted using DFT calculations.

Conclusion:

Four piperidine-conjugated dihydroquinazolinones were synthesized and evaluated against colorectal and colon cancer cell lines. Compound 3d significantly inhibited the growth of HCT116 and A549. Molecular docking studies displayed good fitting of compound 3d by forming different H-bonds with the amino acid at the active sites of the VEGFR2 target. Using a theoretical approach, we optimized HOMO and LUMO plots for the compound 3d.

Current Advances in the Synthesis and Biological Evaluation of Pharmacologically Relevant 1,2,4,5-Tetrasubstituted-1H-Imidazole Derivatives

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In recent years, the synthesis and evaluation of the biological properties of 1,2,4,5-tetrasubstituted-1H-imidazole derivatives have been the subject of a large number of studies by academia and industry. In these studies it has been shown that this large and highly differentiated class of heteroarene derivatives includes high valuable compounds having important biological and pharmacological properties such as antibacterial, antifungal, anthelmintic, anti-inflammatory, anticancer, antiviral, antihypertensive, cholesterol-lowering, antifibrotic, antiuricemic, antidiabetic, antileishmanial and antiulcer activities.

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The present review with 411 references, in which we focused on the literature data published mainly from 2011 to 2017, aims to update the readers on the recent developments on the synthesis and biological evaluation of pharmacologically relevant 1,2,4,5-tetrasubstituted-1H-imidazole derivatives with an emphasis on their different molecular targets and their potential use as drugs to treat various types of diseases. Reference was also made to substantial literature data acquired before 2011 in this burgeoning research area.

Selenium-Catalyzed Carbonylative Synthesis of 3,4-Dihydroquinazolin-2(1H)-one Derivatives with TFBen as the CO Source

An efficient and general carbonylative procedure for the synthesis of 3,4-dihydroquinazolin-2(1H)-one from 1-(halomethyl)-2-nitrobenzenes and aryl/alkyl amines have been explored. In this approach, to avoid of using toxic CO gas, a solid and stable CO precursor, TFBen (benzene-1,3,5-triyl triformate), was utilized. With elemental selenium as the catalyst, a variety of aryl/alkyl amines has been tolerated well to afford the corresponding 3,4-dihydroquinazolin-2(1H)-one products in moderate to excellent yields under mild reaction condition.

A one-pot synthetic approach for the construction of a thiazolo[3,2-a]benzimidazole-linked quinazoline scaffoldviapalladium-catalyzed reactions

4-(2-Substituted-[1,3]thiazolo[3,2-a]benzimidazol-3-yl)quinazolin-2-amines were prepared by the reaction of 2,4-dichloroquinazoline, terminal alkynes, secondary amines, and 1H-benzo[d]imidazole-2(3H)-thione in the presence of palladium catalyst.

Integration of multi-scale molecular modeling approaches with experiments for the in silico guided design and discovery of novel hERG-Neutral antihypertensive oxazalone and imidazolone derivatives and analysis of their potential restrictive effects on cell proliferation

AT1 antagonists is the most recent drug class of molecules against hypertension and they mediate their actions through blocking detrimental effects of angiotensin II (A-II) when acts on type I (AT1) A-II receptor. The effects of AT1 antagonists are not limited to cardiovascular diseases. AT1 receptor blockers may be used as potential anti-cancer agents - due to the inhibition of cell proliferation stimulated by A-II. Therefore, AT1 receptors and the A-II biosynthesis mechanisms are targets for the development of new synthetic drugs and therapeutic treatment of various cardiovascular and other diseases. In this work, multi-scale molecular modeling approaches were performed and it is found that oxazolone and imidazolone derivatives reveal similar/better interaction energy profiles compared to the FDA approved sartan molecules at the binding site of the AT1 receptor. In silico-guided designed hit molecules were then synthesized and tested for their binding affinities to human AT1 receptor in radioligand binding studies, using [¹²⁵I-Sar¹-Ile⁸] AngII. Among the compounds tested, 19d and 9j molecules bound to receptor in a dose response manner and with relatively high affinities. Next, cytotoxicity and wound healing assays were performed for these hit molecules. Since hit molecule 19d led to deceleration of cell motility in all three cell lines (NIH3T3, A549, and H358) tested in this study, this molecule is investigated in further tests. In two cell lines (HUVEC and MCF-7) tested, 19d induced G2/M cell cycle arrest in a concentration dependent manner. Adherent cells detached from the plates and underwent cell death possibly due to apoptosis at 19d concentrations that induced cell cycle arrest.

Structure-based design of hERG-neutral antihypertensive oxazalone and imidazolone derivatives

Angiotensin II receptor type 1 (AT1) antagonists are the most recent drug class against hypertension. Recently first crystal structure of AT1 receptor is deposited to the protein data bank (PDB ID: 4YAY). In this work, several molecular screening methods such as molecular docking and de novo design studies were performed and it is found that oxazolone and imidazolone derivatives reveal similar/better interaction energy profiles compared to the FDA approved sartan molecules at the binding site of the AT1 receptor. A database consisting of 3500-fragments were used to enumerate de novo designed imidazolone and oxazolone derivatives and hereby more than 50000 novel small molecules were generated. These derivatives were then used in high throughput virtual screening simulations (Glide/HTVS) to find potent hit molecules. In addition, virtual screening of around 18 million small drug-like compounds from ZINC database were screened at the binding pocket of the AT1 receptor via Glide/HTVS method. Filtered structures were then used in more sophisticated molecular docking simulations protocols (i.e., Glide/SP; Glide/XP; Glide/IFD; Glide/QPLD, and GOLD). However, the K⁺ ion channel/drug interactions should also be considered in studies implemented in molecular level against their cardiovascular risks. Thus, selected compounds with high docking scores via all diverse docking algorithms are also screened at the pore domain regions of human ether-a-go-go-related gene (hERG1) K⁺ channel to remove the high affinity hERG1 blocking compounds. High docking scored compounds at the AT1 with low hERG1 affinity is considered for long molecular dynamics (MD) simulations. Post-processing analysis of MD simulations assisted for better understanding of molecular mechanism of studied compounds at the binding cavity of AT1 receptor. Results of this study can be useful for designing of novel and safe AT1 inhibitors.

5H-benzo[h]thiazolo[2,3-b]quinazolines ameliorate NDEA-induced hepatocellular carcinogenesis in rats through IL-6 downregulation along with oxidative and metabolic stress reduction

5H-benzo[h]thiazolo[2,3-b]quinazoline scaffold is known to have an antitumor effect on certain types of malignancies; however, its effect on hepatocellular carcinoma (HCC) remains unclear. Previously, we reported p-toluenesulfonic acid-promoted syntheses, molecular modeling and in vitro antitumor activity of 5H-benzo[h]thiazolo[2,3-b]quinazoline against human hepatoma (Hep-G2) cells where compounds 4A and 6A were found to be potent inhibitors among the series. In continuation to our previous effort to develop novel therapeutic strategies for HCC treatment, here we investigated the in vivo antitumor activity and the mechanism underlying the effects of 4A and 6A in N-nitrosodiethylamine (NDEA)-induced HCC using male Wistar rats. NDEA was administered weekly intraperitoneally at a dose of 100 mg/kg for 6 weeks. Various physiological and morphological changes, oxidative parameters, liver marker enzymes and cytokines were assessed to evaluate the antitumor effect of 4A and 6A. In addition, proton nuclear magnetic resonance-based serum metabolomics were performed to analyze the effects of 4A and 6A against HCC-induced metabolic alterations. Significant tumor incidences with an imbalance in carcinogen metabolizing enzymes and cellular redox status were observed in carcinogenic rats. Tumor inhibitory effects of 4A and 6A were noted by histopathology and biochemical profiles in NDEA-induced hepatic cancer. Compounds 4A and 6A had a potential role in normalizing the elevated levels of inflammatory mediators such as interleukin-1β (IL-1β), IL-2, IL-6 and IL-10. At molecular level, the real-time quantitative reverse-transcribed polymerase chain reaction analysis revealed that 4A and 6A attenuated the IL-6 gene overexpression in hepatic cancer. Further, orthogonal partial least squares discriminant analysis scores plot demonstrated a significant separation of 4A and 6A-treated groups from carcinogen control group. Both the compounds have potential to restore the imbalanced metabolites due to HCC, signifying promising hepatoprotective activities. All these findings suggested that 4A and 6A could be potential drug candidates to treat HCC.

p-TSA-promoted syntheses of 5H-benzo[h] thiazolo[2,3-b]quinazoline and indeno[1,2-d] thiazolo[3,2-a]pyrimidine analogs: molecular modeling and in vitro antitumor activity against hepatocellular carcinoma

In our efforts to address the rising incidence of hepatocellular carcinoma (HCC), we have made a commitment to the synthesis of novel molecules to combat Hep-G2 cells. A facile and highly efficient one-pot, multicomponent reaction has been successfully devised utilizing a p-toluenesulfonic acid (p-TSA)-catalyzed domino Knoevenagel/Michael/intramolecular cyclization approach for the synthesis of novel 5H-benzo[h]thiazolo[2,3-b]quinazoline and indeno[1,2-d] thiazolo[3,2-a]pyrimidine analogs bearing a bridgehead nitrogen atom. This domino protocol constructed one new ring by the concomitant formation of multiple bonds (C-C, C-N, and C=N) involving multiple steps without the use of any metal catalysts in one-pot, with all reactants effi-ciently exploited. All the newly synthesized compounds were authenticated by means of Fourier transform infrared spectroscopy, liquid chromatography-mass spectrometry, proton nuclear magnetic resonance spectroscopy, and carbon-13 nuclear magnetic resonance spectroscopy, together with elemental analysis, and their antitumor activity was evaluated in vitro on a Hep-G2 human cancer cell line by sulforhodamine B assay. Computational molecular modeling studies were carried out on cancer-related targets, including interleukin-2, interleukin-6, Caspase-3, and Caspase-8. Two compounds (4A and 6A) showed growth inhibitory activity comparable to the positive control Adriamycin, with growth inhibition of 50% <10 μg/mL. The results of the comprehensive structure-activity relationship study confirmed the assumption that two or more electronegative groups on the phenyl ring attached to the thiazolo[2,3-b]quinazoline system showed the optimum effect. The in silico simulations suggested crucial hydrogen bond and π-π stacking interactions, with a good ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile and molecular dynamics, in order to explore the molecular targets of HCC which were in complete agreement with the in vitro findings. Considering their significant anticancer activity, 4A and 6A are potential drug candidates for the management of HCC.

An insight into the therapeutic potential of quinazoline derivatives as anticancer agents

Cancer is one of the major causes of worldwide human mortality. A wide range of cytotoxic drugs are available on the market, and several compounds are in different phases of clinical trials. Many studies suggest that these cytotoxic molecules are also associated with different types of adverse side effects; therefore researchers around the globe are involved in the development of more efficient and safer anticancer drugs. In recent years, quinazoline and its derivatives have been considered as a novel class of cancer chemotherapeutic agents that show promising activity against different tumors. The aim of this article is to comprehensively review and highlight the recent developments concerning the anticancer activity of quinazoline derivatives as well as offer perspectives on the development of novel quinazoline derivatives as anticancer agents in the near future.

Quinazolines and quinazolinones as ubiquitous structural fragments in medicinal chemistry: An update on the development of synthetic methods and pharmacological diversification

Nitrogen-rich heterocycles, particularly quinazolines and quinazolinones, represent a unique class of diversified frameworks displaying a broad spectrum of biological functions. Over the past several years, intensive medicinal chemistry efforts have generated numerous structurally functionalized quinazoline and quinazolinone derivatives. Interest in expanding the biological effects, demonstrated by these motifs, is growing exponentially, as indicated by the large number of publications reporting the easy accessibility of these skeletons in addition to the diverse nature of synthetic as well as biological applications. Therefore, the main focus of the present review is to provide an ample but condensed overview on various synthetic approaches providing access to quinazoline and quinazolinone compounds with multifaceted biological activities. Furthermore, mechanistic insights, synthetic utilization, structure-activity relationships and molecular modeling inputs for the potent derivatives have also been discussed.