Carbon-to-nitrogen single-atom transmutation of azaarenes

When searching for the ideal molecule to fill a particular functional role (for example, a medicine), the difference between success and failure can often come down to a single atom1. Replacing an aromatic carbon atom with a nitrogen atom would be enabling in the discovery of potential medicines2, but only indirect means exist to make such C-to-N transmutations, typically by parallel synthesis3. Here, we report a transformation that enables the direct conversion of a heteroaromatic carbon atom into a nitrogen atom, turning quinolines into quinazolines. Oxidative restructuring of the parent azaarene gives a ring-opened intermediate bearing electrophilic sites primed for ring reclosure and expulsion of a carbon-based leaving group. Such a 'sticky end' approach subverts existing atom insertion-deletion approaches and as a result avoids skeleton-rotation and substituent-perturbation pitfalls common in stepwise skeletal editing. We show a broad scope of quinolines and related azaarenes, all of which can be converted into the corresponding quinazolines by replacement of the C3 carbon with a nitrogen atom. Mechanistic experiments support the critical role of the activated intermediate and indicate a more general strategy for the development of C-to-N transmutation reactions.

Development of Selective Phosphatidylinositol 5-Phosphate 4-Kinase γ Inhibitors with a Non-ATP-competitive, Allosteric Binding Mode

Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are emerging as attractive therapeutic targets in diseases, such as cancer, immunological disorders, and neurodegeneration, owing to their central role in regulating cell signaling pathways that are either dysfunctional or can be modulated to promote cell survival. Different modes of binding may enhance inhibitor selectivity and reduce off-target effects in cells. Here, we describe efforts to improve the physicochemical properties of the selective PI5P4Kγ inhibitor, NIH-12848 (1). These improvements enabled the demonstration that this chemotype engages PI5P4Kγ in intact cells and that compounds from this series do not inhibit PI5P4Kα or PI5P4Kβ. Furthermore, the first X-ray structure of PI5P4Kγ bound to an inhibitor has been determined with this chemotype, confirming an allosteric binding mode. An exemplar from this chemical series adopted two distinct modes of inhibition, including through binding to a putative lipid interaction site which is 18 Å from the ATP pocket.

Novel 2,4-disubstituted quinazoline analogs as antibacterial agents with improved cytotoxicity profile: Modification of the benzenoid part

Bacterial resistance to currently used antibiotics demands the development of novel antibacterial agents with good safety margins and sufficient efficacy against multi-drug resistant isolates. We have previously described the synthesis of N-butyl-2-(butylthio)quinazolin-4-amine (I) as an optimized hit with broad-spectrum antibacterial activity and low cytotoxicity. In addition, we have identified a potential growing vector for this series of compounds. Herein, we describe further hit optimization which includes systematic diversifications of both the benzenoid part and the substituents at position 6 and 7 of compound I. Growing of the molecule beside the core modifications yielded several compounds with remarkable anti(myco)bacterial activity against a panel of pathogenic bacteria, including drug-resistant strains. Compound 12 showed a 2-4 fold improvement in activity than I against S. aureus Newman, S. pneumoniae DSM-20566 and E. faecalis DSM-20478. The compounds also showed a good safety profile towards human HepG2 cells.

Potentiating the intracellular killing of Staphylococcus aureus by dihydroquinazoline analogues as NorA efflux pump inhibitor

Staphylococcus aureus is an emerging human pathogen that has become difficult to treat due to its high resistance against wide range of drugs. Emergence of drug resistant isolates has further convoluted the treatment process. Among different resistance mechanisms, efflux pump proteins play a central role and has made itself a direct approach for therapeutic exploration. To demarcate the role of dihydroquinazoline analogues as NorA efflux pump inhibitor in S. aureus1199B (NorA over producing) strain total seventeen analogues were synthesized and tested for their modulatory effects on norfloxacin and Etbr resistance. Further accumulation assays, bacterial time kill kinetics, cytotoxicity assay were also carried out. The intracellular killing ability of analogues, as EPI was determined using THP-1 monocytes. The binding interaction of analogues with NorA was also predicted. Dihydroquinazoline analogues notably reduced the MIC of norfloxacin and Etbr in S. aureus1199B. In addition to their very low toxicity, they showed high Etbr and norfloxacin accumulation respectively. Further effective over time log reduction in bacterial kill kinetics in presence of these analogues confirmed their role as NorA efflux pump inhibitor. FESEM analysis clearly depicted their effect on the cell surface morphology owing to its lyses. The most significant finding of this study was the ability of analogues to significantly reduce the intracellular S. aureus1199B in human THP-1 monocytes in presence of norfloxacin. Our study has shown for the first time the possibility of developing the dihydroquinazoline analogues as NorA efflux pump inhibitors for S. aureus and control its infection.

Discovery of quinazoline derivatives as a novel class of potent and in vivo efficacious LSD1 inhibitors by drug repurposing

Histone lysine-specific demethylase 1 (LSD1) is an important epigenetic modulator, and is implicated in malignant transformation and tumor pathogenesis in different ways. Therefore, the inhibition of LSD1 provides an attractive therapeutic target for cancer therapy. Based on drug repurposing strategy, we screened our in-house chemical library toward LSD1, and found that the EGFR inhibitor erlotinib, an FDA-approved drug for lung cancer, possessed low potency against LSD1 (IC₅₀ = 35.80 μM). Herein, we report our further medicinal chemistry effort to obtain a highly water-soluble erlotinib analog 5k (>100 mg/mL) with significantly enhanced inhibitory activity against LSD1 (IC₅₀ = 0.69 μM) as well as higher specificity. In MGC-803 cells, 5k suppressed the demethylation of LSD1, indicating its cellular activity against the enzyme. In addition, 5k had a remarkable capacity to inhibit colony formation, suppress migration and induce apoptosis of MGC803 cells. Furthermore, in MGC-803 xenograft mouse model, 5k treatment resulted in significant reduction in tumor size by 81.6% and 96.1% at dosages of 40 and 80 mg/kg/d, respectively. Our findings indicate that erlotinib-based analogs provide a novel structural set of LSD1 inhibitors with potential for further investigation, and may serve as novel candidates for the treatment of LSD1-overexpressing cancers.

Discovery of N-aryl sulphonamide-quinazoline derivatives as anti-gastric cancer agents in vitro and in vivo via activating the Hippo signalling pathway

Hippo signalling pathway plays a crucial role in tumorigenesis and cancer progression. In this work, we identified an N-aryl sulphonamide-quinazoline derivative, compound 9i as an anti-gastric cancer agent, which exhibited potent antiproliferative ability with IC50 values of 0.36 μM (MGC-803 cells), 0.70 μM (HCT-116 cells), 1.04 μM (PC-3 cells), and 0.81 μM (MCF-7 cells), respectively and inhibited YAP activity by the activation of p-LATS. Compound 9i was effective in suppressing MGC-803 xenograft tumour growth in nude mice without obvious toxicity and significantly down-regulated the expression of YAP in vivo. Compound 9i arrested cells in the G2/M phase, induced intrinsic apoptosis, and inhibited cell colony formation in MGC-803 and SGC-7901 cells. Therefore, compound 9i is to be reported as an anti-gastric cancer agent via activating the Hippo signalling pathway and might help foster a new strategy for the cancer treatment by activating the Hippo signalling pathway regulatory function to inhibit the activity of YAP.

Identification of Spiro-Fused Pyrrolo[3,4-a]pyrrolizines and Tryptanthrines as Potential Antitumor Agents: Synthesis and In Vitro Evaluation

A series of heterocyclic compounds containing a spiro-fused pyrrolo[3,4-a]pyrrolizine and tryptanthrin framework have been synthesized and studied as potential antitumor agents. Cytotoxicity of products was screened against human erythroleukemia (K562) and human cervical carcinoma (HeLa) cell lines. Among the screened compounds. 4a, 4b and 5a were active against human erythroleukemia (K562) cell line, while 4a and 5a were active against cervical carcinoma (HeLa) cell line. In agreement with the DNA cytometry studies, the tested compounds have achieved significant cell-cycle perturbation with higher accumulation of cells in G2/M phase and induced apoptosis. Using confocal microscopy, we found that with 4a and 5a treatment of HeLa cells, actin filaments disappeared, and granular actin was distributed diffusely in the cytoplasm in 76–91% of cells. We discovered that HeLa cells after treatment with compounds 4a and 5a significantly reduced the number of cells with filopodium-like membrane protrusions (from 63 % in control cells to 29% after treatment) and a decrease in cell motility.

From Quinoline to Quinazoline-Based S. aureus NorA Efflux Pump Inhibitors by Coupling a Focused Scaffold Hopping Approach and a Pharmacophore Search

Antibiotic resistance breakers, such as efflux pump inhibitors (EPIs), represent a powerful alternative to the development of new antimicrobials. Recently, by using previously described EPIs, we developed pharmacophore models able to identify inhibitors of NorA, the most studied efflux pump of Staphylococcus aureus. Herein we report the pharmacophore-based virtual screening of a library of new potential NorA EPIs generated by an in-silico scaffold hopping approach of the quinoline core. After chemical synthesis and biological evaluation of the best virtual hits, we found the quinazoline core as the best performing scaffold. Accordingly, we designed and synthesized a series of functionalized 2-arylquinazolines, which were further evaluated as NorA EPIs. Four of them exhibited a strong synergism with ciprofloxacin and a good inhibition of ethidium bromide efflux on resistant S. aureus strains coupled with low cytotoxicity against human cell lines, thus highlighting a promising safety profile.

Determination of the Absolute Configuration of Bioactive Indole-Containing Pyrazino[2,1-b]quinazoline-3,6-diones and Study of Their In Vitro Metabolic Profile

In recent decades, fungi-derived naturally occurring quinazolines have emerged as potential drug candidates. Nevertheless, most studies are conducted for bioactivity assays, and little is known about their absorption, distribution, metabolism, and elimination (ADME) properties. To perform metabolic studies, the synthesis of the naturally occurring quinazolinone, fiscalin B (1), and its chloro derivative, 4-((1H-indol-3-yl)methyl)-8,10-dichloro-1-isobutyl-1,2-dihydro-6H-pyrazino[2,1-b]quinazoline-3,6(4H)-dione (2), disclosed as an antibacterial agent, was performed in a gram scale using a microwave-assisted polycondensation reaction with 22% and 17% yields, respectively. The structure of the non-natural (+)-fiscalin B was established, for the first time, by X-ray crystallography as (1R,4S)-1, and the absolute configuration of the naturally occurring fiscalin B (-)-1 was confirmed by comparison of its calculated and experimental electronic circular dichroism (ECD) spectra as (1S,4R)-1. in vitro metabolic studies were monitored for this class of natural products for the first time by ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS). The metabolic characteristics of 1 and 2 in human liver microsomes indicated hydration and hydroxylation mass changes introduced to the parent drugs.

Synthesis, Anticancer Screening of Some Novel Trimethoxy Quinazolines and VEGFR2, EGFR Tyrosine Kinase Inhibitors Assay; Molecular Docking Studies

A new series of 8-methoxy-2-trimethoxyphenyl-3-substituted quinazoline-4(3)-one compounds were designed, synthesized, and screened for antitumor activity against three cell lines, namely, Hela, A549, and MDA compared to docetaxel as reference drug. The molecular docking was performed using Autodock Vina program and 20 ns molecular dynamics (MD) simulation was performed using GROMACS 2018.1 software. Compound 6 was the most potent antitumor of the new synthesized compounds and was evaluated as a VEGFR2 and EGFR inhibitor with (IC50, 98.1 and 106 nM respectively) compared to docetaxel (IC50, 89.3 and 56.1 nM respectively). Compounds 2, 6, 10, and 8 showed strong cytotoxic activities against the Hela cell line with IC50 of, 2.13, 2.8, 3.98, and 4.94 µM, respectively, relative to docetaxel (IC50, 9.65 µM). Compound 11 showed strong cytotoxic activity against A549 cell line (IC50, 4.03 µM) relative to docetaxel (IC50, 10.8 µM). Whereas compounds 6 and 9 showed strong cytotoxic activity against MDA cell line (IC50, 0.79, 3.42 µM, respectively) as compared to docetaxel (IC50, 3.98 µM).

Potential of substituted quinazolines to interact with multiple targets in the treatment of cancer

The efficacy of quinazoline-based antiglioma agents has been attributed to their effects on microtubule dynamics.1,2 The design, synthesis and biological evaluation of quinazolines as potent inhibitors of multiple intracellular targets, including microtubules and multiple RTKs, is described. In addition to the known ability of quinazolines 1 and 2 to cause microtubule depolymerization, they were found to be low nanomolar inhibitors of EGFR, VEGFR-2 and PDGFR-β. Low nanomolar inhibition of EGFR was observed for 1-3 and 9-10. Compounds 1 and 4 inhibited VEGFR-2 kinase with activity better than or equal to that of sunitinib. In addition, compounds 1 and 2 had similar potency to sunitinib in the CAM angiogenesis assay. Multitarget activities of compounds in the present study demonstrates that the quinazolines can affect multiple pathways and could lead to these agents having antitumor potential caused by their activity against multiple targets.

Synthesis, Antibacterial, and Antioxidant Evaluation of Novel Series of Condensed Thiazoloquinazoline with Pyrido, Pyrano, and Benzol Moieties as Five- and Six-Membered Heterocycle Derivatives

A novel synthesis of thiazolo[2,3-b]quinazolines 4(a–e), pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines {5(a–e), 6(a–e), and 7(a–e)}, pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines 8(a–e), and benzo[4,5]thiazolo[2,3-b]quinazoloine9(a–e) derivatives starting from 2-(Bis-methylsulfanyl-methylene)-5,5-dimethyl-cyclohexane-1,3-dione 2 as efficient α,α dioxoketen dithioacetal is reported and the synthetic approaches of these types of compounds will provide an innovative molecular framework to the designing of new active heterocyclic compounds. In our study, we also present optimization of the synthetic method along with a biological evaluation of these newly synthesized compounds as antioxidants and antibacterial agents against the bacterial strains, like S. aureus, E. coli, and P. aeruginosa. Among all the evaluated compounds, it was found that some showed significant antioxidant activity at 10 μg/mL while the others exhibited better antibacterial activity at 100 μg/mL. The results of this study showed that compound 6(c) possessed remarkable antibacterial activity, whereas compound 9(c) exhibited the highest efficacy as an antioxidant. The structures of the new synthetic compounds were elucidated by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR.

Design, synthesis and molecular modeling studies of 2-styrylquinazoline derivatives as EGFR inhibitors and apoptosis inducers

Herein, we report the synthesis of novel 2-substituted styrylquinazolines conjugated with aniline or sulfonamide moieties, anticipated to act as potent anticancer therapeutic agents through preferential EGFR inhibition. In doing so, all the synthesized compounds were screened for their in vitro anticancer activities (nine subpanels) at the National Cancer Institute (NCI), USA. The resulting two most active anticancer compounds (7b and 8c) were then chemically manipulated to investigate feasible derivatives (12a-e and 15a-d). MTT cytotoxicity, in vitro cell free EGFR and anti-proliferative activity against EGFR/ A549 cell line evaluation for the most active broadly spectrum candidates (7a/b, 8c/e, 12b and 15d) was conducted. Promising results were obtained for the styrylquinazoline-benzenesulfonamide derivative 8c (IC50 = 8.62 µM, 0.190 µM and = 79.25%), if compared to lapatanib (IC50 = 11.98 µM, 0.190 µM, and 79.25%), respectively. Moreover, its apoptotic induction potential was studied through cell cycle analysis, Annexin-V and caspase-3 activation assays. Results showed a clear cell arrest at G2/M phase, a late apoptotic increase (76 folds) and a fruitful caspase-3 expression change (8 folds), compared to the control. Finally, molecular docking studies of compounds 7a/b, 8c/e, 12b and 15d revealed proper fitting into the active site of EGFR with a low binding energy score for compound 8c (-13.19 Kcal/mole), compared to lapatanib (-14.54 Kcal/mole).

Design, synthesis and biological evaluation of new bivalent quinazoline analogues as IAP antagonists

We recently reported the biological evaluations of monovalent IAP antagonist 7 with good potency (MDA-MB-231, IC₅₀ = 19 nM). In an effort to increase cellular activity and improve favorable drug-like properties, we newly designed and synthesized bivalent analogues based on quinazoline structure of 7. Optimization of cellular potency and CYP inhibition led to the identification of 27, which showed dramatic increase of over 100-fold (IC₅₀ = 0.14 nM) and caused substantial tumor regressions in MDA-MB-231 xenograft model. These results strongly support 27 as a promising bivalent antagonist for the development of an effective anti-tumor approaches.

Antitumor activity, multitarget mechanisms, and molecular docking studies of quinazoline derivatives based on a benzenesulfonamide scaffold: Cell cycle analysis

The in vitro cytotoxicity of some substituted quinazolinones, 1-15, was evaluated using NCI (10 µM) in a full NCI 59-cell line panel assay. Relative to the reference drug, imatinib (PCE = 20/59), compounds 3, 4, 7, 9, and 10 exhibited remarkable antitumor activity against the tested cell lines, with positive cytotoxic effects (PCE) of 29/59, 18/59, 17/59, 44/59, and 24/59 respectively. Enzymatic inhibitory assay conducted on 3, 4, 9, and 10 as the most potent antitumor agents against EGFR, HER2 and CDK9 kinases, and COX-2 enzyme. Compound 3 possessed good COX-2 inhibitory activity (IC50 = 0.775 μM) compared to the reference drug, celecoxib (IC50 = 0.153 μM). Compounds 4 and 9 were closely potent to the reference compounds against EGFR and (HER2) tyrosine kinases, with IC50 values of 90.17 (and 131.39 for HER2) for 4 and 145.35 (and 129.07 for HER2) nM for 9; the reference drugs in this case, namely, gefitinib and erlotinib, exhibited IC50 values of 55.58 (90) and 110 (79.28) nM against the EGFR and (HER2) tyrosine kinases, respectively. Compound 4 was approximately similar potent against CDK9 kinase (IC50 = 67.04 nM) like the reference compound, dinaciclib (IC50 = 53.12 nM). Compound 9 induced cytotoxicity in the MCF-7 cell line (GI % at 10.0 μM = 47%) through pre-G1 apoptosis, thereby inhibiting cell growth at the G2/M phase. Molecular docking models of 3 and 4 with COX-2, EGFR, and CDK9 were conducted to determine their binding mode within the putative binding pockets.

Identification of 4-anilino-6-aminoquinazoline derivatives as potential MERS-CoV inhibitors

New therapies for treating coronaviruses are urgently needed. A series of 4-anilino-6-aminoquinazoline derivatives were synthesized and evaluated to show high anti-MERS-CoV activities. N4-(3-Chloro-4-fluorophenyl)-N6-(3-methoxybenzyl)quinazoline-4,6-diamine (1) has been identified in a random screen as a hit compound for inhibiting MERS-CoV infection. Throughout optimization process, compound 20 was found to exhibit high inhibitory effect (IC50 = 0.157 μM, SI = 25) with no cytotoxicity and moderate in vivo PK properties.

Recent Advances in the Synthesis of Perimidines and their Applications

Perimidines are versatile scaffolds and a fascinating class of N-heterocycles that have evolved significantly in recent years due to their immense applications in life sciences, medical sciences, and industrial chemistry. Their ability of molecular interaction with different proteins, complex formation with metals, and distinct behavior in various ranges of light makes them more appealing and challenging for future scientists. Various novel technologies have been developed for the selective synthesis of perimidines and their conjugated derivatives. These methods extend to the preparation of different bioactive and industrially applicable molecules. This review aims to present the most recent advancements in perimidine synthesis under varied conditions like MW radiation, ultrasound, and grinding using different catalysts such as ionic liquids, acid, metal, and nanocatalyst and also under green environments like catalyst and solvent-free synthesis. The applications of perimidine derivatives in drug discovery, polymer chemistry, photo sensors, dye industries, and catalytic activity in organic synthesis are discussed in this survey. This article is expected to be a systematic, authoritative, and critical review on the chemistry of perimidines that compiles most of the state-of-art innovation in this area.

Larvicidal Activities of 2-Aryl-2,3-Dihydroquinazolin -4-ones against Malaria Vector Anopheles arabiensis, In Silico ADMET Prediction and Molecular Target Investigation

Malaria, affecting all continents, remains one of the life-threatening diseases introduced by parasites that are transmitted to humans through the bites of infected Anopheles mosquitoes. Although insecticides are currently used to reduce malaria transmission, their safety concern for living systems, as well as the environment, is a growing problem. Therefore, the discovery of novel, less toxic, and environmentally safe molecules to effectively combat the control of these vectors is in high demand. In order to identify new potential larvicidal agents, a series of 2-aryl-1,2-dihydroquinazolin-4-one derivatives were synthesized and evaluated for their larvicidal activity against Anopheles arabiensis. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the compounds were also investigated and most of the derivatives possessed a favorable ADMET profile. Computational modeling studies of the title compounds demonstrated a favorable binding interaction against the acetylcholinesterase enzyme molecular target. Thus, 2-aryl-1,2-dihydroquinazolin-4-ones were identified as a novel class of Anopheles arabiensis insecticides which can be used as lead molecules for the further development of more potent and safer larvicidal agents for treating malaria.

In Vitro Inhibition of Hsp90 Protein by Benzothiazoloquinazolinequinones Is Enhanced in The Presence of Ascorbate. A Preliminary In Vivo Antiproliferative Study

A series of benzo[g]benzothiazolo[2,3-b]quinazoline-7,12-quinones were prepared from 2-acylnaphthohydroquinones and 2-aminobenzothiazoles and were evaluated for their in vitro antiproliferative activity. After screening using the MTT reduction assay, their IC50 values were calculated on a panel of cancer cells (T24, DU-145, MCF-7). Current standard anticancer drugs were included as control, and their calculated IC50 values were 7.8 and 23.5 µM for 5-fluorouracil and tamoxifen, respectively. Non-cancer cells (AG1523) were included to assess cancer cell sensitivity and drug selectivity. Four members of the series, with IC50 values from 0.11 to 2.98 µM, were chosen for further assays. The selected quinones were evaluated regarding their effects on cancer cell proliferation (clonogenic assay) and on Hsp90 and poly(ADPribose)polymerase (PARP) protein integrity. The most active compound (i.e., 15) substantially inhibited colony forming unit (CFU) formation at 0.25 µM. In the presence of ascorbate, it induced an oxidative cleavage of Hsp90 but had no effect on PARP protein integrity. In an in vivo animal model, it discreetly increased the mean survival time (m.s.t.) of tumor-bearing mice. In light of these results, compound 15 represents a potential lead-molecule to be further developed.

Synthesis, cytotoxic evaluation, and molecular docking studies of novel quinazoline derivatives with benzenesulfonamide and anilide tails: Dual inhibitors of EGFR/HER2

We synthesized a new series of 2-[(3-(4-sulfamoylphenethyl)-4(3H)-quinazolinon-2-yl)thio]anilide derivatives (2-16) and evaluated their cytotoxic activity against breast adenocarcinoma (MCF-7), colorectal adenocarcinoma (HT-29), and acute myeloid leukemia (HL-60 and K562) cells. To reveal their selectivity toward cancer cells, the compounds were also tested against the human fibroblast cell line, MRC-5. Compounds 1-5 exhibited potent cytotoxic activity against the tested cell lines with IC50 values of 0.65-3.86, 0.68-4.60, 0.41-1.45, 0.42-4.07, and 3.77-25.55 μM, respectively compared to sorafenib, the standard drug (IC50 2.50, 2.50, and 3.14 μM against MCF-7, HT-29, and HL60 cells, respectively). Interestingly, compounds 1-5 displayed selectivity toward the cancer cell lines over MRC-5 (IC50 3.77-25.55 μM). These compounds also displayed potent inhibitory activity against EGFR and HER2 kinases (IC50 0.09-0.43 and 0.15-0.33 μM, respectively) compared to the standard drug, sorafenib (IC50 0.11 and 0.13 μM, respectively). Likewise, compounds 1, 4, and 5 showed strong inhibitory activity against VEGFR2 (IC50 0.34, 0.28 and 0.39 μM, respectively) compared to sorafenib (IC50 0.17 μM). We also employed molecular docking to identify the structural features required for the EGFR/HER2 inhibitory activity of the new series. Ultimately, compounds 1, 4, and 5 were demonstrated to be candidates for further preclinical investigations.

High-selective HDAC6 inhibitor promotes HDAC6 degradation following autophagy modulation and enhanced antitumor immunity in glioblastoma

Glioblastoma is the most fatal type of primary brain cancer, and current treatments for glioblastoma are insufficient. HDAC6 is overexpressed in glioblastoma, and siRNA-mediated knockdown of HDAC6 inhibits glioma cell proliferation. Herein, we report a high-selective HDAC6 inhibitor, J22352, which has PROTAC (proteolysis-targeting chimeras)-like property resulted in both p62 accumulation and proteasomal degradation, leading to proteolysis of aberrantly overexpressed HDAC6 in glioblastoma. The consequences of decreased HDAC6 expression in response to J22352 decreased cell migration, increased autophagic cancer cell death and significant tumor growth inhibition. Notably, J22352 reduced the immunosuppressive activity of PD-L1, leading to the restoration of host anti-tumor activity. These results demonstrate that J22352 promotes HDAC6 degradation and induces anticancer effects by inhibiting autophagy and eliciting the antitumor immune response in glioblastoma. Therefore, this highly selective HDAC6 inhibitor can be considered a potential therapeutic for the treatment of glioblastoma and other cancers.

New pyrido[3,4-g]quinazoline derivatives as CLK1 and DYRK1A inhibitors: synthesis, biological evaluation and binding mode analysis

Cdc2-like kinase 1 (CLK1) and dual specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) are involved in the regulation of alternative pre-mRNA splicing. Dysregulation of this process has been linked to cancer progression and neurodegenerative diseases, making CLK1 and DYRK1A important therapeutic targets. Here we describe the synthesis of new pyrido[3,4-g]quinazoline derivatives and the evaluation of the inhibitory potencies of these compounds toward CDK5, CK1, GSK3, CLK1 and DYRK1A. Introduction of aminoalkylamino groups at the 2-position resulted in several compounds with low nanomolar affinity and selective inhibition of CLK1 and/or DYRK1A. Their evaluation on several immortalized or cancerous cell lines showed varying degree of cell viability reduction. Co-crystal structures of CLK1 with two of the most potent compounds revealed two alternative binding modes of the pyrido[3,4-g]quinazoline scaffold that can be exploited for future inhibitor design.

Introduction of pyrrolidineoxy or piperidineamino group at the 4-position of quinazoline leading to novel quinazoline-based phosphoinositide 3-kinase delta (PI3Kδ) inhibitors

Phosphoinositide 3-kinase Delta (PI3Kδ) plays a key role in B-cell signal transduction and inhibition of PI3Kδ was confirmed to have clinical benefit in certain types of activation of B-cell malignancies. Herein, we reported a novel series of 4-pyrrolidineoxy or 4-piperidineamino substituted quinazolines, showing potent PI3Kδ inhibitory activities. Among these compounds, 12d, 14b and 14c demonstrated higher potency against PI3Kδ with the half maximal inhibitory concentration (IC50) values of 4.5, 3.0, and 3.9 nM, respectively, which were comparable to idelalisib (IC50 = 2.7 nM). The further PI3K isoforms selectivity evaluation showed that compounds 12d, 14b and 14c have excellent PI3Kδ selectivity over PI3Kα, PI3Kβ, and PI3Kγ. Moreover, compounds 12d, 14b and 14c also displayed different anti-proliferative profiles against a panel of four human B cell lines including Ramos, Raji, RPMI-8226, and SU-DHL-6. The molecular docking simulation indicated several key hydrogen bonding interactions were formed. This study suggests the introduction of pyrrolidineoxy or piperidineamino groups into the 4-position of quinazoline leads to new potent and selective PI3Kδ inhibitors.

Multidirectional desymmetrization of pluripotent building block en route to diastereoselective synthesis of complex nature-inspired scaffolds

Octahydroindolo[2,3-a]quinolizine ring system forms the basic framework comprised of more than 2000 distinct family members of natural products. Despite the potential applications of this privileged substructure in drug discovery, efficient, atom-economic and modular strategies for its assembly, is underdeveloped. Here we show a one-step build/couple/pair strategy that uniquely allows access to diverse octahydroindolo[2,3-a]quinolizine scaffolds with more than three contiguous chiral centers and broad distribution of molecular shapes via desymmetrization of the oxidative-dearomatization products of phenols. The cascade demonstrates excellent diastereoselectivity, and the enantioselectivity exceeded 99% when amino acids are used as chiral reagents. Furthermore, two diastereoselective reactions for the synthesis of oxocanes and piperazinones, is reported. Phenotypic screening of the octahydroindolo[2,3-a]quinolizine library identifies small molecule probes that selectively suppress mitochondrial membrane potential, ATP contents and elevate the ROS contents in hepatoma cells (Hepa1-6) without altering the immunological activation or reprogramming of T- and B-cells, a promising approach to cancer therapy.

Syntheses, antiviral activities and induced resistance mechanisms of novel quinazoline derivatives containing a dithioacetal moiety

A series of novel quinazoline derivatives containing a dithioacetal moiety were designed and synthesized, and their structures were characterized by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, and high-resolution mass spectrometry. Bioassay results indicated that compound 4b exhibited remarkable protective activity against cucumber mosaic virus (CMV, EC50 = 248.6 μg/mL) and curative activity against potato virus Y (EC50 = 350.5 μg/mL), which were better than those of ningnanmycin (357.7 μg/mL and 493.7 μg/mL, respectively). Moreover, compound 4b could increase the chlorophyll content in plants, improve photosynthesis, and effectively induce tobacco anti-CMV activity.

Development of Kinase Inhibitors via Metal-Catalyzed C⁻H Arylation of 8-Alkyl-thiazolo[5,4-f]-quinazolin-9-ones Designed by Fragment-Growing Studies

Efficient metal catalyzed C⁻H arylation of 8-alkyl-thiazolo[5,4-f]-quinazolin-9-ones was explored for SAR studies. Application of this powerful chemical tool at the last stage of the synthesis of kinase inhibitors allowed the synthesis of arrays of molecules inspired by fragment-growing studies generated by molecular modeling calculations. Among the potentially active compounds designed through this strategy, FC162 (4c) exhibits nanomolar IC50 values against some kinases, and is the best candidate for the development as a DYRK kinase inhibitor.

Synthesis and antitumor activity of novel 6,7,8-trimethoxy N-aryl-substituted-4-aminoquinazoline derivatives

A series of 6,7,8-trimethoxy N-aryl-substituted-4-aminoquinazoline derivatives were synthesized as epidermal growth factor receptor (EGFR) inhibitors, and their antitumor activities were assessed in the gastric cancer cell line SGC7901 using MTT assay. All compounds of Tg1-14 were found to inhibit SGC7901 cell proliferation, and compound Tg11 (IC₅₀ = 0.434 μM) was found to be slightly more effective against SGC7901 cells than epirubicin (IC₅₀ = 5.16 μM). This suggests that compound Tg11 can be used as a new substitution structure to develop more efficacious antitumor agents. Western blot analysis showed that treatment with Tg11 (40 μM for 30 min) resulted in near complete inhibition of EGF-induced ERK1/2 phosphorylation, indicating that its anti-proliferative effect is largely associated with inhibition of ERK1/2 activation. These data imply that Tg11 is a potential anticancer agent capable of inhibiting cell proliferation.

SYNTHESIS OF THE NEW 2-(3,4-DIHYDRO-3-OXO-2H-[1,2,4]TRIAZINO[4,3-C]QUINAZOLIN-4-YL) ACETIC ACID DERIVATIVES AND ANALYSIS OF THEIR ANTIOXIDANT ACTIVITY IN NITROSATIVE STRESS MODELS

Today we know that NO· and ONOO- are clue pathophysiological factors for progression some ischemic diseases of the central nervous system. So investigation of the antioxidants which will be able to decrease NO· and ONOO- toxicity seems to be very of current interest. The six esters and three amides of 2-(3,4-dihydro-3-oxo-2H-[1,2,4]triazino[4,3-c]quinazolin-4-yl)acetic acid were synthesized for this study, and we showed evidence of antioxidant activity of these new original derivatives. We studied the effect of 2-(3,4-dihydro-3-oxo-2H-[1,2,4]triazino[4,3-c]quinazolin-4-yl)acetic acid derivatives on superoxide dismutase activity under the condition of excessive NO· and ONOO- production. NO· induction was performed by the action of light on sodium nitroprusside Na2[Fe(NO)(CN)5]×2H2O in vitro. Also, the investigation of the substances was carried out in the brain supernatant obtained from the white Wistar rats in vivo. For nitrosative stress modeling dinitrozolic complex of Fe2+ and cysteine were utilized. Our data showed that 2-(3,4-dihydro-3-oxo-2H-[1,2,4]triazino[4,3-c]quinazolin-4-yl)acetic acid is not active compound while its esters and amides have antioxidant activity. Compound benzyl ester of this acid revealed the most effective antioxidant activity.

Novel series of 6-(2-substitutedacetamido)-4-anilinoquinazolines as EGFR-ERK signal transduction inhibitors in MCF-7 breast cancer cells

Epidermal growth factor receptor (EGFR) signaling pathway has been previously investigated for its significant role in the progression of different types of malignant tumors, where development of small molecules targeting EGFR is well known strategy for design of antitumor agents. Herein, we report the design and synthesis of two series of 6-(2-substitutedacetamido)-4-anilinoquinazolines (6a-x and 13a-d) as EGFR inhibitors. All the newly synthesized quinazoline derivatives were in vitro evaluated for their anti-proliferative activity towards MCF-7 (Breast Cancer) and HepG2 (Hepatocellular carcinoma) cell lines. In particular, compound 6n showed significant inhibitory activity against MCF-7 and HepG2 cell lines (IC₅₀ = 3 and 16 μM, respectively), compared to that of Erlotinib (IC₅₀ = 20 and 25 μM, respectively). Western blotting of 6n at MCF-7 cell line revealed the dual inhibitory activity of 6n towards diminishing the phosphorylated levels for EGFR and ERK. Also, ELISA assay confirmed the anti-EGFR activity of compound 6n (IC₅₀ = 0.037 μM). Finally, a molecular docking study showed the potential binding mode of 6n within the ATP catalytic binding site of EGFR, exhibiting similar binding mode to EGFR inhibitor Erlotinib.

Design, Synthesis and Antitumor Evaluation of Novel Pyrazolopyrimidines and Pyrazoloquinazolines

A series of N-aryl-7-aryl-pyrazolo[1,5-a]pyrimidines 18a⁻u and N-aryl-pyrazolo[1,5-a]quinazolines 25a⁻c were designed and synthesized via the reaction of 5-aminopyrazoles 11a⁻c with enaminones 12a⁻g or 19, respectively. The new compounds were screened for their in vitro antitumor activity toward liver (HepG-2) and breast (MCF-7) human cancer cells using 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide MTT assay. From the results, it was found that all compounds showed dose-dependent cytotoxic activities against both HepG-2 and MCF-7 cells. Two compounds 18o and 18a were selected for further investigations. Cell cycle analysis of liver (HepG-2) cells treated with 18o and breast (MCF-7) cells treated with 18a showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.

6,7-Dimorpholinoalkoxy quinazoline derivatives as potent EGFR inhibitors with enhanced antiproliferative activities against tumor cells

A series of novel 6,7-dimorpholinoalkoxy quinazoline derivatives was designed, synthesized and evaluated as potent EGFR inhibitors. Most of synthesized derivatives exhibited moderate to excellent antiproliferative activities against five human tumor cell lines. Compound 8d displayed the most remarkable inhibitory activities against tumor cells expressing wild type (A431, A549 and SW480 cells) or mutant (HCC827 and NCI-H1975 cells) epidermal growth factor receptor (EGFR) (with IC₅₀ values in the range of 0.37-4.87 μM), as well as more potent inhibitory effects against recombinant EGFR tyrosine kinase (EGFR-TK, wt or T790M) (with the IC₅₀ values of 7.0 and 9.3 nM, respectively). Molecular docking showed that 8d can form four hydrogen bonds with EGFR, and two of them were located in the Asp855-Phe856-Gly857 (DFG) motif of EGFR. Meanwhile, 8d can significantly block EGF-induced EGFR activation and the phosphorylation of its downstream proteins such as Akt and Erk1/2 in human NSCLC cells. Also, 8d mediated cell apoptosis and the prolongation of cell cycle progression in G0/G1-phase in A549 cells. The work would have remarkable implications for further design and development of more potent EGFR tyrosine kinase inhibitors (TKIs).

Design, Synthesis and Anti-inflammatory Activity of Derivatives 10-R-3-Aryl-6,7-dihydro-2H-[1,2,4] triazino[2,3-c]quinazolin-2-ones of Spiro-fused Cyclic Frameworks

Present work is devoted to the purposeful search of novel promising anti-inflammatory agents among the insufficiently known 3'-R-10'-R1-spiro[hetaryl-3(4),6'-[1,2,4]triazino[2,3-c]quinazolin]-2'(7'H)-ones. The virtual combinatorial library of previously unknown spiro-condensed derivatives of [1,2,4]triazino[2,3-c]quinazolines was formed and promising COX-2 inhibitors were identified by molecular docking method. Potential anti-inflammatory agents were synthesized by [5+1]-cyclocondensation of substituted 3-(2-aminophenyl)-6-R-1,2,4-triazin-5(2H)-ones with heterocyclic ketones. The structures of synthsized compounds were verified by complex of physicochemical methods and spectral characteristics features were discussed. Obtained compounds were studied for anti-inflammatory activity using formalin induced paw edema model and highly active compounds were identified. Conducted SAR-analysis showed that combination of triazino[2,3-c] quinazoline moiety with spiro-condensed fragments is a reasonable approach for creating novel anti-inflammatory agents.

Discovery of Benzo[g]quinazolin benzenesulfonamide derivatives as dual EGFR/HER2 inhibitors

An array of some new N-(substituted)-2-((4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydrobenzo[g]quinazolin-2-yl)thio)acetamide 5-19 were synthesized from the starting compound 4-(2-mercapto-4-oxobenzo[g]quinazolin-3(4H)-yl)benzenesulfonamide 4, to be assessed for their cytotoxic activity against A549 lung cancer cell line and to determine their inhibitory effect on EGFR tyrosine kinase enzyme. Compounds 5-19 showed high activity towards A549 cell line with IC50 values of 0.12-8.70 μM. Compounds 6, 12 and 18 were the most potent in this series. These compounds were further screened as dual inhibitors for EGFR/HER2 enzymes in comparison with erlotinib and were found to possess very potent activity. Compound 12 showed the highest activity with IC50 values of 0.06 μM and 0.30 μM towards EGFR and HER2, respectively. Accordingly, the apoptotic effect of the most potent compounds 6, 12 and 18 was investigated and showed a marked increase in the level of caspases-3 by 6, 9 and 8 folds, respectively, compared to the control cells. Moreover, Molecular modeling was performed inside the active site of EGFR, keeping in mind their binding possibilities, bond lengths, angles and energy scores. It was found that the most active compounds demonstrated the best binding scores in the active site of EGFR, which may clarify their high inhibition profile.

Design, synthesis, antiviral bioactivity and three-dimensional quantitative structure-activity relationship study of novel ferulic acid ester derivatives containing quinazoline moiety

BACKGROUND

Ferulic acid and quinazoline derivatives possess good antiviral activities. In order to develop novel compounds with high antiviral activities, a series of ferulic acid ester derivatives containing quinazoline were synthesized and evaluated for their antiviral activities.

RESULTS

Bioassays indicated that some of the compounds exhibited good antiviral activities in vivo against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). One of the compounds demonstrated significant curative and protective activities against TMV and CMV, with EC₅₀ values of 162.14, 114.61 and 255.49, 138.81 mg L^-1 , respectively, better than those of ningnanmycin (324.51, 168.84 and 373.88, 272.70 mg L^-1 ). The values of q² and r² for comparative molecular field analysis and comparative molecular similarity index analysis in the TMV (0.508, 0.663 and 0.992, 0.930) and CMV (0.530, 0.626 and 0.997, 0.981) models presented good predictive abilities.

CONCLUSION

Some of the title compounds demonstrated good antiviral activities. Three-dimensional quantitative structure-activity relationship models revealed that the antiviral activities depend on steric and electrostatic properties. These results could provide significant structural insights for the design of highly active ferulic acid derivatives. © 2017 Society of Chemical Industry.

Design, Synthesis, and Antitumor Activity of Novel Quinazoline Derivatives

In an attempt to explore a new class of epidermal growth factor receptor (EGFR) inhibitors, novel 4-stilbenylamino quinazoline derivatives were synthesized through a Dimorth rearrangement reaction and characterized via IR, ¹H-NMR, ¹³C-NMR, and HRMS. Methoxyl, methyl, halogen, and trifluoromethyl groups on stilbeneamino were detected. These synthesized compounds were evaluated for antitumor activity in vitro against eight human tumor cell lines with an MTS assay. Most synthesized compounds exhibited more potent activity (IC₅₀ = ~2.0 μM) than gefitinib (IC₅₀ > 10.0 μM) against the A431, A549, and BGC-823 cell lines. Docking methodology of compound 6c and 6i binding into the ATP site of EGFR was carried out. The results showed that fluorine and trifluoromethyl played an important role in efficient cell activity.

Structure-based design, synthesis and crystallization of 2-arylquinazolines as lipid pocket ligands of p38α MAPK

In protein kinase research, identifying and addressing small molecule binding sites other than the highly conserved ATP-pocket are of intense interest because this line of investigation extends our understanding of kinase function beyond the catalytic phosphotransfer. Such alternative binding sites may be involved in altering the activation state through subtle conformational changes, control cellular enzyme localization, or in mediating and disrupting protein-protein interactions. Small organic molecules that target these less conserved regions might serve as tools for chemical biology research and to probe alternative strategies in targeting protein kinases in disease settings. Here, we present the structure-based design and synthesis of a focused library of 2-arylquinazoline derivatives to target the lipophilic C-terminal binding pocket in p38α MAPK, for which a clear biological function has yet to be identified. The interactions of the ligands with p38α MAPK was analyzed by SPR measurements and validated by protein X-ray crystallography.

Development of a series of novel 4-anlinoquinazoline derivatives possessing quinazoline skeleton: Design, synthesis, EGFR kinase inhibitory efficacy, and evaluation of anticancer activities in vitro

4-anilinoquinazoline-based derivatives represent an attractive scaffold for small molecular EGFR-TKIs in the field of medicinal chemistry. A series of novel heterocyclic substituted derivatives have been designed, synthesized and evaluated their antitumor bioactivities as potential EGFR-TKIs. Most of the new compounds exhibited certain efficient inhibition potency for proliferation of a panel of five human cancer cells with IC₅₀ values at the low micromolar level, and some of them possessed good broad-spectrum inhibition activities, compared to Gefitinib. Especially, the IC₅₀ values of compound 21 against HepG2, A549, MCF-7, DU145 and SH-SY5Y cells were 4.61, 9.50, 9.80, 6.79 and 7.77 μM, respectively, which were much lower than those of Gefitinb. Furthermore, the highlighting compound 21 demonstrated excellent inhibition activity against EGFR-TK with the IC₅₀ value of 3.62 nM, similar to that of Gefitinib(2.21 nM). The results of LDH release assay proved that compound 21 was anti-proliferative rather than cytotoxicity on HepG2 cells. Compound 21 were able to cause HepG2 cells to block in S phase and induce cell death mainly by apoptosis through a mitochondrial dependent pathway. Moreover, the assessment of MMP, the determination of intracellular free Ca²⁺ concentration, the production of ROS, and the effects on the activity of caspase-3 in a dose-dependent manner demonstrated that compound 21 induced cell apoptosis in HepG2 cells through the Ca²⁺/ROS-mediated mitochondria/caspase-dependent apoptosis pathway largely. These preliminary results evidenced that compound 21 could be a potential antitumor agent deserving further study.

Synthetic Fluororutaecarpine Inhibits Inflammatory Stimuli and Activates Endothelial Transient Receptor Potential Vanilloid-Type 1

The natural product, rutaecarpine (RUT), is the main effective component of Evodia rutaecarpa which is a widely used traditional Chinese medicine. It has vasodilation, anticoagulation, and anti-inflammatory activities. However, further therapeutic applications are limited by its cytotoxicity. Thus, a derivative of RUT, 10-fluoro-2-methoxyrutaecarpine (F-RUT), was designed and synthesized that showed no cytotoxicity toward RAW264.7 macrophages at 20 μM. In an anti-inflammation experiment, it inhibited the production of nitric oxide (NO) and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages; cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) induced by LPS were also downregulated. After 24 h of treatment, F-RUT significantly inhibited cell migration and invasion of ovarian A2780 cells. Furthermore, F-RUT promoted expressions of transient receptor potential vanilloid type 1 (TRPV1) and endothelial (e)NOS in human aortic endothelial cells, and predominantly reduced the inflammation in ovalbumin/alum-challenged mice. These results suggest that the novel synthetic F-RUT exerts activities against inflammation and vasodilation, while displaying less toxicity than its lead compound.

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.

Effective killing of cancer cells and regression of tumor growth by K27 targeting sulfiredoxin

Cancer cells have been suggested to be more susceptible to oxidative damages and highly dependent on antioxidant capacity in comparison with normal cells, and thus targeting antioxidant enzymes has been a strategy for effective cancer treatment. Sulfiredoxin (Srx) is an enzyme that catalyzes the reduction of sulfinylated peroxiredoxins and thereby reactivates them. In this study we developed a Srx inhibitor, K27 (N-[7-chloro-2-(4-fluorophenyl)-4-quinazolinyl]-N-(2-phenylethyl)-β-alanine), and showed that it induces the accumulation of sulfinylated peroxiredoxins and oxidative stress, which leads to mitochondrial damage and apoptotic death of cancer cells. The effects of K27 were significantly reversed by ectopic expression of Srx or antioxidant N-acetyl cysteine. In addition, K27 led to preferential death of tumorigenic cells over non-tumorigenic cells, and suppressed the growth of xenograft tumor without acute toxicity. Our results suggest that targeting Srx might be an effective therapeutic strategy for cancer treatment through redox-mediated cell death.

Synthesis, molecular modeling and NAD(P)H:quinone oxidoreductase 1 inducer activity of novel 2-phenylquinazolin-4-amine derivatives

Reactive oxygen species (ROS) play an integral role in the pathogenesis of most diseases. This work presents the design and synthesis of novel 2-phenylquinazolin-4-amine derivatives (2-12) and evaluation of their

NAD(P)H

quinone oxidoreductase 1 (NQO1) inducer activity in murine cells. Also, molecular docking of all the new compounds was performed to assess their ability to inhibit Keap1-Nrf2 protein-protein interaction through occupying the Keap1-Nrf2-binding domain which biologically leads to a consequent Nrf2 accumulation and enhanced gene expression of NQO1. Docking results showed that all compounds have the ability to interact with Keap1; however compound 7, the most active compound in this study, showed more interactions with key amino acids.

Antimicrobial and Cytotoxic Evaluation of New Quinazoline Derivatives

The synthesis of nine new quinazoline derivatives (2a-2i) and evaluation of their antimicrobial and cytotoxic activities were aims of the present work. For the synthesis of the compounds, 2-chloro-6,7-dimethoxyquinazolin-4-amine was used as the initial starting material. The intermediate product, 2-hydrazinyl-6,7- dimethoxyquinazolin-4-amine, was reacted with appropriate aromatic aldehydes to obtain 2-(2-benzylidenehydrazinyl)-6,7-dimethoxyquinazolin-4-amine derivatives as final compounds. The structures of the compounds were elucidated by (1)H- and (13)C-NMR, IR, and-MS analyses. The new pure compounds were evaluated for their potential antimicrobial and cytotoxic activities using in vitro microdilution and cell culture techniques, respectively. The compounds 2e and 2f may be promising candidates for the treatment of fungal infections with their activity and cytotoxicity.

Exploiting 1,2,3-Triazolium Ionic Liquids for Synthesis of Tryptanthrin and Chemoselective Extraction of Copper(II) Ions and Histidine-Containing Peptides

Based on a common structural core of 4,5,6,7-tetrahydro[1,2,3]triazolo[1,5-a]pyridine, a number of bicyclic triazolium ionic liquids 1–3 were designed and successfully prepared. In our hands, this optimized synthesis of ionic liquids 1 and 2 requires no chromatographic separation. Also in this work, ionic liquids 1, 2 were shown to be efficient ionic solvents for fast synthesis of tryptanthrin natural product. Furthermore, a new affinity ionic liquid 3 was tailor-synthesized and displayed its effectiveness in chemoselective extraction of both Cu(II) ions and, for the first time, histidine-containing peptides.

NAD(P)H:quinone oxidoreductase 1 inducer activity of some novel anilinoquinazoline derivatives

The Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements pathway enables cells to survive oxidative stress conditions through regulating the expression of cytoprotective enzymes such as

NAD(P)H

quinone oxidoreductase 1 (NQO1). This work presents the design and synthesis of novel anilinoquinazoline derivatives (2-16a) and evaluation of their NQO1 inducer activity in murine cells. Molecular docking of the new compounds was performed to assess their ability to inhibit Keap1-Nrf2 protein-protein interaction through occupying the Keap1-Nrf2-binding domain, which leads to Nrf2 accumulation and enhanced gene expression of NQO1. Docking results showed that all compounds can potentially interact with Keap1; however, 1,5-dimethyl-2-phenyl-4-(2-phenylquinazolin-4-ylamino)-1,2-dihydropyrazol-3-one (9), the most potent inducer, showed the largest number of interactions with key amino acids in the binding pocket (Arg483, Tyr525, and Phe478) compared to the native ligand or any other compound in this series.

Pharmacokinetics and In Vitro Blood-Brain Barrier Screening of the Plant-Derived Alkaloid Tryptanthrin

The indolo[2,1-b]quinazoline alkaloid tryptanthrin was previously identified as a potent anti-inflammatory compound with a unique pharmacological profile. It is a potent inhibitor of cyclooxygenase-2, 5-lipooxygenase-catalyzed leukotriene synthesis, and nitric oxide production catalyzed by the inducible nitric oxide synthase. To characterize the pharmacokinetic properties of tryptanthrin, we performed a pilot in vivo study in male Sprague-Dawley rats (2 mg/kg bw i. v.). Moreover, the ability of tryptanthrin to cross the blood-brain barrier was evaluated in three in vitro human and animal blood-brain barrier models. Bioanalytical UPLC-MS/MS methods used were validated according to current international guidelines. A half-life of 40.63 ± 6.66 min and a clearance of 1.00 ± 0.36 L/h/kg were found in the in vivo pharmacokinetic study. In vitro data obtained with the two primary animal blood-brain barrier models showed a good correlation with an immortalized human monoculture blood-brain barrier model (hBMEC cell line), and were indicative of a high blood-brain barrier permeation potential of tryptanthrin. These findings were corroborated by the in silico prediction of blood-brain barrier penetration. P-glycoprotein interaction of tryptanthrin was assessed by calculation of the efflux ratio in bidirectional permeability assays. An efflux ratio below 2 indicated that tryptanthrin is not subjected to active efflux.

Design, synthesis and biological evaluation of 4-anilinoquinazoline derivatives as new c-myc G-quadruplex ligands

A series of 4-anilinoquinazoline derivatives were designed and synthesized as novel c-myc promoter G-quadruplex binding ligands. Subsequent biophysical and biochemical evaluation demonstrated that the introduction of aniline group at 4-position of quinazoline ring and two side chains with terminal amino group improved their binding affinity and stabilizing ability to G-quadruplex DNA. RT-PCR assay and Western blot showed that compound 7a could down-regulate transcription and expression of c-myc gene in Hela cells, which was consistent with the behavior of an effective G-quadruplex ligand targeting c-myc oncogene. More importantly, RTCA and colony formation assays indicated that 7a obviously inhibited Hela cells proliferation, without influence on normal primary cultured mouse mesangial cells. Flow cytometric assays suggested that 7a induced Hela cells to arrest in G0/G1 phase both in a time-dependent and dose-dependent manner.

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.

Anilinoquinazoline inhibitors of the RET kinase domain-Elaboration of the 7-position

We have previously reported a series of anilinoquinazoline derivatives as potent and selective biochemical inhibitors of the RET kinase domain. However, these derivatives displayed diminished cellular potency. Herein we describe further optimisation of the series through modification of their physicochemical properties, delivering improvements in cell potency. However, whilst cellular selectivity against key targets could be maintained, combining cell potency and acceptable pharmacokinetics proved challenging.

Discovery and optimization of 1,7-disubstituted-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-ones as potent and selective PKCθ inhibitors

A high-throughput screening campaign helped us to identify an initial lead compound (1) as a protein kinase C-θ (PKCθ) inhibitor. Using the docking model of compound 1 bound to PKCθ as a model, structure-based drug design was employed and two regions were identified that could be explored for further optimization, i.e., (a) a hydrophilic region around Thr442, unique to PKC family, in the inner part of the hinge region, and (b) a lipophilic region at the forefront of the ethyl moiety. Optimization of the hinge binder led us to find 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one as a potent and selective hinge binder, which resulted in the discovery of compound 5. Filling the lipophilic region with a suitable lipophilic substituent boosted PKCθ inhibitory activity and led to the identification of compound 10. The co-crystal structure of compound 10 bound to PKCθ confirmed that both the hydrophilic and lipophilic regions were fully utilized. Further optimization of compound 10 led us to compound 14, which demonstrated an improved pharmacokinetic profile and inhibition of IL-2 production in a mouse.