Design, synthesis, molecular docking and anticonvulsant evaluation of novel 6-iodo-2-phenyl-3-substituted-quinazolin-4(3H)-ones

Synthesis, structural characterization, DFT calculations, molecular docking, and molecular dynamics simulations of a novel ferrocene derivative to unravel its potential antitumor activity

In this article, we describe a set of subsequent five-steps chemical reactions to synthesize a ferrocene derivative named 1-(5-(diphenylphosphaneyl)cyclopenta-1,3-dien-1-yl)ethyl)imino)-1,3-dihydroisobenzofuran-5-yl)methanol (compound 10). Structural characterization of 10 and its intermediate products was also performed and reported to attest to their formation. A molecular docking study was performed to propose the novel synthesized ferrocene derivative (10) as a potential antitumor candidate targeting the mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1. The computed docking score of (10) at -9.50 kcal/mol compared to the native anticancer staurosporine at -8.72 kcal/mol postulated a promising anticancer activity. Also, molecular dynamics (MD) simulations were carried out for 500 ns followed by MM-GBSA-binding free energy calculations for both the docked complexes of ferrocene and staurosporine to give more deep insights into their dynamic behavior in physiological conditions. Furthermore, DFT calculations were performed to unravel some of the physiochemical characteristics of the ferrocene derivative (10). The quantum mechanics calculations shed the light on some of the structural and electrochemical configurations of (10) which would open the horizon for further investigation. HighlightsThe synthesis of a ferrocene derivative named 1-(5-(diphenylphosphaneyl)cyclopenta-1,3-dien-1-yl)ethyl)imino)-1,3-dihydroisobenzofuran-5-yl)methanol (compound 10) was described.Structural characterizations of ferrocene derivative (10) and its intermediate products were also performed.DFT calculations, molecular docking, molecular dynamics, and MM-GBSA calculations were carried out.Computational studies revealed the antitumor potential of ferrocene derivative (10) through targeting and inhibiting mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1.Communicated by Ramaswamy H. Sarma.

Design, synthesis, and SAR studies of novel 4-methoxyphenyl pyrazole and pyrimidine derivatives as potential dual tyrosine kinase inhibitors targeting both EGFR and VEGFR-2

Guided by the pharmacophoric features of both EGFR and VEGFR-2 antagonists, two novel series of 4-methoxyphenyl pyrazole and pyrimidine derivatives [(4a-c) and (5a-c, 6, 7a-c, 8, 9, 10, 11a,c, 12, 13a-c, 14a-c, and 15a,b)], respectively, were designed and synthesized as dual EGFR/VEGFR-2 inhibitors. Interestingly, compound 12 showed very strong antiproliferative effects towards all the five studied cell lines (HepG-2, MCF-7, MDA-231, HCT-116, and Caco-2) with IC₅₀ values of 3.74, 7.81, 4.85, 2.96, and 9.27 µM, respectively. Also, it achieved the highest inhibitory activities against both EGFR and VEGFR-2 as well (IC₅₀ = 0.071 and 0.098 µM) compared to the two reference drugs, erlotinib (IC₅₀ = 0.063 µM) and sorafenib (IC₅₀ = 0.041 µM), respectively. Moreover, four compounds (4a, 7a, 7c, and 12) were selected for further evaluation through cell cycle analysis and Annexin V-based flow cytometry assay in the HepG-2 cell line. In addition, deep computational studies including molecular docking, physicochemical properties, profiling pharmacokinetics, ADMET studies, and toxicity predictions were performed for the designed compounds to evaluate the prospective drug candidates. Finally, analyzing the structure-activity relationship (SAR) of the new derivatives gives us a lot of interesting promising results which could help medicinal chemists to design more potent drug candidates soon as well.

Mahmoud S, Shehata M, Shama NMA, GabAllah M, Mostafa-Hedeab G, Marzouk MM. Naturally Available Flavonoid Aglycones as Potential Antiviral Drug Candidates against SARS-CoV-2

Flavonoids are important secondary plant metabolites that have been studied for a long time for their therapeutic potential in inflammatory diseases because of their cytokine-modulatory effects. Five flavonoid aglycones were isolated and identified from the hydrolyzed aqueous methanol extracts of Anastatica hierochuntica L., Citrus reticulata Blanco, and Kickxia aegyptiaca (L.) Nabelek. They were identified as taxifolin (1), pectolinarigenin (2), tangeretin (3), gardenin B (4), and hispidulin (5). These structures were elucidated based on chromatographic and spectral analysis. In this study, molecular docking studies were carried out for the isolated and identified compounds against SARS-CoV-2 main protease (Mpro) compared to the co-crystallized inhibitor of SARS-CoV-2 Mpro (α-ketoamide inhibitor (KI), IC50 = 66.72 µg/mL) as a reference standard. Moreover, in vitro screening against SARS-CoV-2 was evaluated. Compounds 2 and 3 showed the highest virus inhibition with IC50 12.4 and 2.5 µg/mL, respectively. Our findings recommend further advanced in vitro and in vivo studies of the examined isolated flavonoids, especially pectolinarigenin (2), tangeretin (3), and gardenin B (4), either alone or in combination with each other to identify a promising lead to target SARS-CoV-2 effectively. This is the first report of the activity of these compounds against SARS-CoV-2.

Design and Synthesis of New Quinoxaline Derivatives as Potential Histone Deacetylase Inhibitors Targeting Hepatocellular Carcinoma: In Silico, In Vitro, and SAR Studies

Guided by the structural optimization principle and the promising anticancer effect of the quinoxaline nucleus, a new series of novel HDAC inhibitors were designed and synthesized. The synthesized compounds were designed to bear the reported pharmacophoric features of the HDAC inhibitors in addition to an extra moiety to occupy the non-used vacant deep pocket of the HDAC receptor. The newly prepared compounds were evaluated for their in vitro anti-proliferative activities against HepG-2 and HuH-7 liver cancer cell lines. The tested compounds showed promising anti-proliferative activities against both cell lines. The most active ten candidates (6 c , 6 d , 6 f , 6 g , 6 k , 6 l , 7 b , 8, 10 h , and 12) were further evaluated for their effect on the gene expression levels of Bax as an apoptotic marker and Bcl-2 as an anti-apoptotic one. Moreover, they were evaluated for their ability to inhibit histone deacetylase (HDAC1, HDAC4, and HDAC6) activities. Compound 6 c achieved the best cytotoxic activities on both HepG-2 and HuH-7 cell lines with IC50 values of 1.53 and 3.06 µM, respectively, and also it showed the most inhibitory activities on HDAC1, HDAC4, and HDAC6 with IC50 values of 1.76, 1.39, and 3.46 µM, respectively, compared to suberoylanilide hydroxamic acid (SAHA) as a reference drug (IC50 = 0.86, 0.97, and 0.93 µM, respectively). Furthermore, it achieved a more characteristic arrest in the growth of cell population of HepG-2 at both G0/G1 and S phases with 1.23-, and 1.18-fold, respectively, compared to that of the control, as determined by cell cycle analysis. Also, compound 6 c showed a marked elevation in the AnxV-FITC apoptotic HepG-2 cells percentage in both early and late phases increasing the total apoptosis percentage by 9.98-, and 10.81-fold, respectively, compared to the control. Furthermore, docking studies were carried out to identify the proposed binding mode of the synthesized compounds towards the prospective target (HDAC4). In silico ADMET and toxicity studies revealed that most of the synthesized compounds have accepted profiles of drug-likeness with low toxicity. Finally, an interesting SAR analysis was concluded to help the future design of more potent HDACIs in the future by medicinal chemists.

Phthalazine-based VEGFR-2 inhibitors: Rationale, design, synthesis, in silico, ADMET profile, docking, and anticancer evaluations

In the designed compounds, a new linker was inserted in the form of fragments with verified VEGFR-2 inhibitory potential, including an α,β-unsaturated ketonic fragment, pyrazole, and pyrimidine. Also, new distal hydrophobic moieties were attached to these linkers that are expected to increase the hydrophobic interaction with VEGFR-2 and, consequently, the affinity. These structural optimizations have led us to identify the novel dihydropyrazole derivative 6_e as a promising hit molecule. All the new derivatives were evaluated to assess their anticancer activity against three human cancer cell lines, including HepG2, HCT-116, and MCF-7. The results of the in vitro anticancer evaluation study revealed the moderate to excellent cytotoxicity of 6_c , 6_e , 6_g , and 7_b , with IC₅₀ values in the low micromolar range. The inhibitory activity of VEGFR-2 was investigated for 16 of the designed compounds. The enzyme assay results of the new compounds were compared with those of sorafenib as a reference VEGFR-2 inhibitor. The obtained results demonstrated that our derivatives are potent VEGFR-2 inhibitors. The most potent derivatives 6_c , 6_e , 6_g , and 7_b showed IC₅₀ values in the range of 0.11-0.22 µM. Molecular docking and pharmacokinetic studies were also conducted to rationalize the VEGFR-2 inhibitory activity and to evaluate the ability of the most potent derivatives to be developed as good drug candidates.

Recent advancement in the discovery and development of anti-epileptic biomolecules: An insight into structure activity relationship and Docking

Although there have been many advancements in scientific research and development, the cause of epilepsy still remains an open challenge. In spite of high throughput research in the field of anti-epileptic drugs, efficacy void is still prevalent before the researchers. Researchers have persistently been exploring all the possibilities to curb undesirable side effects of the anti-epileptic drugs or looking for a more substantial approach to diminish or cure epilepsy. The drug development has shown a hope to medicinal chemists and researchers to carry further research by going through a substantial literature survey. This review article attempts to describe the recent developments in the anti-epileptic agents, pertaining to different molecular scaffolds considering their structure-activity relationship, docking studies and their mechanism of actions.

Novel 3-Substituted-2, 3-Dihydro-2-Thioxoquinazolin-4-(1H)-one derivative as Anticonvulsants: Synthesis, Molecular Docking and Pharmacological Screening

Background:

According to the World Health Organization, 50 million people worldwide are suffering from epilepsy, making it one of the most common neurological diseases globally. 2,3 disubstituted quinazolinone-4-one derivatives endowed with various pharmacological activity, particularly having anticonvulsant action.

Objectives:

The aim of this study was to synthesize 3-Substituted-2,3-Dihydro-2-thioxoquinazolin- 4-(1H)-one derivative and evaluate for anticonvulsant activity and neurotoxicity in order to find an efficient, compound with lesser side effects.

Methods:

A novel series of 3-[4-(2-amino-5, 6-dihydro-4(substituted phenyl)-4H-1, 3-oxazin /thiazin-6yl) phenyl]-2, 3-dihyro-2-thioxoquinazolin-4(1H)-one derivatives (4a-4p) were synthesized. The structures of the synthesized compounds were assigned on the basis of spectral data (UV, IR, 1HNMR, 13CNMR and MS) and performed anticonvulsant activity against maximal electroshock test and Subcutaneous Pentylenetetrazole model. Neurotoxicity was assessed using a rotarod apparatus test. The molecular docking study was performed to assess their binding affinities towards Gamma-Aminobutyric Acid type A receptor. A quantitative estimate of drug-likeness was also performed, which calculates the molecular properties and screen the molecules based on drug-likeness rules.

Results:

Compounds 4b, 4e, 4j and 4m have shown the highest anticonvulsant activity against tonic seizure with decreased mean duration of tonic hind leg extension of 8.31, 7.35, 8.61 and 8.99 s, respectively in maximal electroshock model and increased onset time clonic convulsion duration of 94.45, 96.65, 93.51 and 91.86 s in Subcutaneous Pentylenetetrazole model. Molecular docking study revealed a better binding affinity with Gamma-Aminobutyric Acid type A receptor.

Conclusion:

The compound 4b and 4e emerged out as the pilot molecule with a better anticonvulsant activity without any neurotoxicity. The obtained results showed that compounds 4b and 4e could be useful as a template for future design, optimization, and investigation to produce more active analogs.

Synthesis, in vivo and in silico anticonvulsant activity studies of new derivatives of 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)acetamide

In order to expand the arsenal of biologically active substances of anticonvulsive action by the interaction of 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)acetic acid with the corresponding amines in the presence of N,N'-carbonyldiimidazole in the dioxane medium, a systematic series of 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)-N-R-acetamides was obtained. A novel approach to synthesis of the key intermediate - 2-(2,4-dioxo-1,4-dihydro-quinazolin-3(2H)-yl)acetic acid was developed. The structure and purity of the resulting substances was confirmed by elemental analysis, ¹H NMR, ¹³C NMR spectroscopy and LC/MS. Based on the results of docking studies using SCIGRESS software, selected compounds with the best affinity for anticonvulsant protein biomes (PDB codes: 4COF, 3F8E and 1 EOU) are promising for experimental studies of anticonvulsant activity. A comparative analysis of the results of molecular docking and in vivo results suggests that there is a positive correlation between scoring protein inhibition and experimental data. Pharmacological studies have revealed the leader compound 2-(2,4-dioxo-1,4-dihydroquinazolin-3(2H)-yl)-N-[(2,4-dichlorophenyl)methyl]acet-amide, which improved all the experimental convulsive syndrome rates in mice without motor coordination impairment and may be recommended for further research. The lowest values of the scoring function of the ligand-peptide interaction are obtained for the synthesized compound and сarbonic anhydrase II (gene name CA2) (PDB code 1 EOU), so its inhibition is proposed by us as the most probable mechanism of the anticonvulsive effect of the leader compound.

Evaluation of Anticonvulsant Activity and Toxicity Screening of Semicarbazones Derived from Quinazolinone Scaffold

Background:

Epilepsy is one of the most prevalent noncommunicable neurological conditions. More than 10 million people in India are afflicted with epilepsy. Treatment available has many detrimental side effects. Up to one-third of epilepsy patients remain resistance to optimum drug treatment. These facts triggered the further scope and search for newer more effective and less toxic anticonvulsants.

Methods:

Quinazolinone semicarbazone derivatives showing protection in chemoconvulsant induced seizure models (as reported in our previous study) were further screened in MES and scPTZ induced seizure models. Neurotoxicity was determined; quantification of anticonvulsant activity and toxicity was also done. Finally compounds were screened by liver functional test to ascertain the possible hepatotoxicity in the active compounds.

Results:

Compounds N-1- (menthone) -N- [3-(4-(substituted)-phenyl) -4-oxo- 3,4-dihydroquinazolin- 2-yl] methyl semicarbazone (3A-d-4, 3B-d-4 and 3C-d-4) showed significant protection in both MES and scPTZ induced seizure model with no neurotoxicity at the given dose. In MES test, compounds showed an ED50 close to that of phenytoin and carbamazepine. They also showed Protective Index (PI) higher as compared to phenytoin and carbamazepine. A high safety profile (HD50/ED50 values) was noted and hypnosis, analgesia, and anesthesia were only observed at higher doses.

Conclusion:

Compounds showed no significant increase or decrease in the concentration of alkaline phosphatase, Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), albumin and bilirubin.

Synthesis, Anticonvulsant Activity, and SAR Study of Novel 4-Quinazolinone Derivatives

Series of N-(4-substitutedphenyl)-4-(1-methyl (or 1,2-dimethyl)-4-oxo-1,2-dihydroquinazolin-3(4H)-yl)-alkanamides (5a-j) and 4-chloro-N'-((1-methyl (or 1,2-dimethyl)-4-oxo-1,2-dihydroquinazolin-3(4H)-yl)-alkaloyl)benzohydrazides (6a-f) were designed based on the previously reported essential structural features for anticonvulsant activity. Several amino acids were incorporated within the synthesized quinazolin-4(3H)-ones to improve their bioavailability and the anticonvulsant activity. Synthesis of the target compounds was accomplished in four steps starting from the reaction between N-methyl isatoic anhydride and the appropriate amino acid. Then, the carboxylic acid group was utilized to synthesize the required final structures. The new quinazolinone derivatives were evaluated for their anticonvulsant activity according to the Anticonvulsant Drug Development (ADD) Program protocol. All the 16 new quinazolinones exhibited good anticonvulsant activity; especially 5f, 5b, and 5c showed superior anticonvulsant activities in comparison to the reference drug, with ED₅₀ values of 28.90, 47.38, and 56.40 mg/kg, respectively.

Synthesis, Modelling, and Anticonvulsant Studies of New Quinazolines Showing Three Highly Active Compounds with Low Toxicity and High Affinity to the GABA-A Receptor

Some novel fluorinated quinazolines (5a–j) were designed and synthesized to be evaluated for their anticonvulsant activity and their neurotoxicity. Structures of all newly synthesized compounds were confirmed by their infrared (IR), mass spectrometry (MS) spectra, ¹H nuclear magnetic resonance (NMR), ¹³C-NMR, and elemental analysis (CHN). The anticonvulsant activity was evaluated by a subcutaneous pentylenetetrazole (scPTZ) test and maximal electroshock (MES)-induced seizure test, while neurotoxicity was evaluated by a rotorod test. The molecular docking was performed for all newly-synthesized compounds to assess their binding affinities to the GABA-A receptor in order to rationalize their anticonvulsant activities in a qualitative way. The data obtained from the molecular modeling was correlated with that obtained from the biological screening. These data showed considerable anticonvulsant activity for all newly-synthesized compounds. Compounds 5b, 5c, and 5d showed the highest binding affinities toward the GABA-A receptor, along with the highest anticonvulsant activities in experimental mice. These compounds also showed low neurotoxicity and low toxicity in the median lethal dose test compared to the reference drugs. A GABA enzymatic assay was performed for these highly active compounds to confirm the obtained results and explain the possible mechanism for anticonvulsant action. The most active compounds might be used as leads for future modification and optimization.

Synthesis and Pharmacological Evaluation of New 3,4-Dihydroisoquinolin Derivatives Containing Heterocycle as Potential Anticonvulsant Agents

Two novel series of 3,4-dihydroisoquinolin with heterocycle derivatives (4a–t and 9a–e) were synthesized and evaluated for their anticonvulsant activity using maximal electroshock (MES) test and pentylenetetrazole (PTZ)-induced seizure test. All compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, and mass spectral data. Among them, 9-(exyloxy)-5,6-dihydro-[1,2,4]triazolo[3,4-a]isoquinolin-3(2H)-one (9a) showed significant anticonvulsant activity in MES tests with an ED₅₀ value of 63.31 mg/kg and it showed wide margins of safety with protective index (PI > 7.9). It showed much higher anticonvulsant activity than that of valproate. It also demonstrated potent activity against PTZ-induced seizures. A docking study of compound 9a in the benzodiazepine (BZD)-binding site of γ-aminobutyric acid_A (GABA_A) receptor confirmed possible binding of compound 9a with the BZD receptors.

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.