Synthesis and biological evaluation of novel tricyclic oxazine and oxazepine fused quinazolines. Part 1: Erlotinib analogs

Two series of novel tricyclic oxazine and oxazepine fused quinazolines have been designed and synthesized. The in vitro antitumor effect of the title compounds was screened on N87, A431, H1975, BT474 and Calu-3 cell lines. Compared to erlotinib and gefitinib, compounds 1a–1h were found to demonstrate more potent antitumor activities. Several derivatives could counteract EGF-induced phosphorylation of EGFR in cells, and their potency was comparable to the reference compounds. Compounds 1a–1h were chosen for further evaluation of EGFR and HER2 in vitro kinase inhibitory activity. Compounds 1b–1f, 1h effectively inhibited the in vitro kinase activity of EGFR and HER2 with similar efficacy as erlotinib and gefitinib.     

Design and synthesis of a novel class EGFR/HER2 dual inhibitors containing tricyclic oxazine fused quinazolines scaffold

Two series of novel tricyclic oxazine and oxazepine fused quinazolines have been designed, synthesized and evaluated for their inhibitory activity against EGFR and HER2. Structure-activity relationship (SAR) of these compounds was discussed. From the SAR studies, we found that intramolecular cyclization which possessed a functional Michael acceptor group can enhance the antitumor activities. Compounds 1e and 1h were identified as lead compounds which displayed almost 3–4 times more potent inhibition of EGFR and HER2 than the approved drug lapatinib. The satisfactory physicochemical properties of these compounds were also supported by ACD labs. The results presented here will promote the development of newer dual inhibitors of EGFR and HER2.     

Synthesis,biological evaluation and molecular docking studies of amide-coupled benzoic nitrogen mustard derivatives as potential antitumor agents

A series of amide-coupled benzoic nitrogen mustard derivatives as potential EGFR and HER-2 kinase inhibitors were synthesized and reported for the first time. Some of them exhibited significant EGFR and HER-2 inhibitory activity. Of all the studied compounds, compounds 5b and 5t exhibited the most potent inhibitory activity, which was comparable to the positive control erlotinib. Docking simulation was performed to position compounds 5b and 5t into the EGFR active site to determine the probable binding model. Antiproliferative assay results indicated that some of the benzoic nitrogen mustard derivatives possessed high antiproliferative activity against MCF-7. In particular, compounds 5b and 5t with potent inhibitory activity in tumor growth inhibition may function as potential antitumor agents.     

Development of hydroxamate-based histone deacetylase inhibitors containing 1,2,4-oxadiazole moiety core with antitumor activities

Histone deacetylases (HDACs) has proved to be promising target for the development of antitumor drugs. In this study, we reported the design and synthesis of a class of novel hydroxamate-based bis-substituted aromatic amide HDAC inhibitors with 1,2,4-oxadiazole core. Most newly synthesized compounds displayed excellent HDAC1 inhibitory effects and significant anti-proliferative activities. Among them, compounds 11a and 11c increased acetylation of histone H3 and H4 in dose-dependent manner. Furthermore, 11a and 11c remarkably induced apoptosis in HepG2 cancer cells. Finally, the high potency of compound 11a was rationalized by molecular docking studies.     

Design,synthesis and biological evaluation of chrysin long-chain derivatives as potential anticancer agents

A series of long-chain derivatives of chrysin (compounds 3–22) were synthesized to evaluate for their antiproliferative activities against the human liver cancer cell line HT-29 and EGFR inhibitory activity. Among the compounds tested, compounds hexadecyl 2-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy)acetate (10) and N-hexadecyl 2-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy)acetamide (20) displayed potent EGFR inhibitory activity with IC₅₀ values of 0.048 μM and 0.035 μM), comparable to the positive control erlotinib. Docking simulation of compounds 10 and 20 was carried out to illustrate the binding mode of the molecular into the EGFR active site, and the result suggested that compound 10 and 20 can bind the EGFR kinase well. Thus, compounds 10 and 20 with potent EGFR inhibitory activity would be potential anticancer agents.     

Discovery and Biological evaluation of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives as potent Bruton’s tyrosine kinase inhibitors

Aberrant activation of B cell receptor (BCR) signal transduction cascade contributes to the propagation and maintenance of B cell malignancies. The discovery of mall molecules with high potency and selectivity against Bruton’s tyrosine kinase (BTK), a key signaling molecule in this cascade, is particularly urgent in modern treatment regimens. Herein, a series of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives were reported as potent BTK inhibitors. Compounds 17 and 18 displayed strong BTK inhibitory activities in the enzymatic inhibition assay, with the IC₅₀ values of 1.2 and 0.8 nM, respectively, which were comparable to that of ibrutinib (IC₅₀ = 0.6 nM). Additionally, compound 17 had a more selective profile over EGFR than ibrutinib. According to the putative binding poses, the molecular basis of this series of compounds with respect to potency against BTK and selectivity over EGFR was elucidated. In further experiments at cellular level, compounds 17 and 18 significantly inhibited the proliferation of Ramos and TMD8 cells. And they arrested 75.4% and 75.2% of TMD8 cells in G1 phase, respectively, at the concentration of 1 µM.     

Discovery of new [1,4]dioxino[2,3-f]quinazoline-based inhibitors of EGFR including the T790M/L858R mutant

A novel series of 2,3-dihydro-[1,4]dioxino[2,3-f]quinazoline derivatives were designed, synthesized and evaluated as reversible and noncovalent epidermal growth factor receptor (EGFR) inhibitors. Most of the compounds exhibited good potency against EGFR^wt and some showed moderate to excellent potency against EGFR^T790M/L858R mutant. The half-maximal inhibitory concentration (IC₅₀) values of twenty-one compounds against EGFR^wt were less than 50 nM, and those of six compounds were less than 10 nM. The IC₅₀ values of eleven compounds against EGFR^T790M/L858R were less than 100 nM. Among these, compound b1 displayed the most potent inhibitory activity against EGFR^wt (IC₅₀ = 2.0 nM) and EGFR^T790M/L858R (IC₅₀ = 6.9 nM). Compounds with excellent inhibitory activities against EGFR^wt and EGFR^T790M/L858R kinase inhibitory activities showed good antiproliferative activities against H358 and A549 cells. Docking study was performed to position compound b1 into the EGFR active pocket to determine the probable binding conformation.     

Molecular dynamics guided development of indole based dual inhibitors of EGFR (T790M) and c-MET

Secondary acquired mutation in EGFR, i.e. EGFR T790M and amplification of c-MET form the two key components of resistant NSCLC. Thus, previously published pharmacophore models of EGFR T790M and c-MET were utilized to screen an in-house database. On the basis of fitness score, indole-pyrimidine scaffold was selected for further evaluation. Derivatives of indole-pyrimidine scaffold with variedly substituted aryl substitutions were sketched and then docked in both the targets. These docked complexes were then subjected to molecular dynamic simulations, to study the stability of the complexes and evaluate orientations of the designed molecules in the catalytic domain of the selected kinases. Afterwards, the complexes were subjected to MM-GBSA calculation, to study the effect of substitutions on binding affinity of double mutant EGFR towards these small molecules. Finally, the designed molecules were synthesized and evaluated for their inhibitory potential against both the kinases using in vitro experiments. Additionally, the compounds were also evaluated against EGFR (L858R) to determine their selectivity towards double mutant, resistant kinase [EGFR (T790M)]. Compound 7a and 7c were found to be possess nanomolar range inhibitory (IC₅₀) potential against EGFR (T790M), 7 h showed good inhibitory potential against c-MET with IC₅₀ value of 0.101 µM. Overall, this work is one of the earliest report of compounds having significant dual inhibitory potential against secondary acquired EGFR and cMET, with IC₅₀ values in nanomolar range.     

Design,synthesis and biological evaluation of novel aryl-acrylic derivatives as novel indoleamine-2,3-dioxygenase 1 (IDO1) inhibitors

Two series of novel aryl-acrylic derivatives were designed, synthesized, and screened in enzymatic and cellular inhibitory activities. All compounds showed moderate to significant potency. The SAR analyses indicated that the semicarbazone linker is better than the 1,2,3-triazole linker. Among semicarbazone compounds that R₁ bearing di-chain amino groups exhibited superior activities to those with morpholino group. Furthermore, compounds with electron-withdrawing groups at the 2-position or 4-position on the terminal phenyl ring were more active. Among these, compounds 7g, 7i, 7m and 7n exhibited the inhibitory potency in the low micromolar range and displayed negligible level of cytotoxicity against normal HeLa cells. In addition, the study suggested that the aryl-acrylic is an interesting novel scaffold for IDO1 inhibition for further development.     

Design,synthesis and anticancer evaluation of thieno[2,3-d]pyrimidine derivatives as dual EGFR/HER2 inhibitors and apoptosis inducers

Deregulation of many kinases is directly linked to cancer development and the tyrosine kinase family is one of the most important targets in current cancer therapy regimens. In this study, we have designed and synthesized a series of thieno[2,3-d]pyrimidine derivatives as an EGFR and HER2 tyrosine kinase inhibitors. All the synthesized compounds were evaluated in vitro for their inhibitory activities against EGFR^WT; and the most active compounds that showed promising IC₅₀ values against EGFR^WT were tested in vitro for their inhibitory activities against mutant EGFR^T790M and HER2 kinases. Moreover, the antitumor activities of these compounds were tested against four cancer cell lines (HepG2, HCT-116, MCF-7 and A431). Compounds 13g, 13h and 13k exhibited the highest activities against the examined cell lines with IC₅₀ values ranging from 7.592 ± 0.32 to 16.006 ± 0.58 µM comparable to that of erlotinib (IC₅₀ ranging from 4.99 ± 0.09 to 13.914 ± 0.36 µM). Furthermore, the most potent antitumor agent (13k) was selected for further studies to determine its effect on the cell cycle progression and apoptosis in MCF-7 cell line. The results indicated that this compound arrests G₂/M phase of the cell cycle and it is a good apoptotic agent. Finally, molecular docking studies showed a good binding pattern of the synthesized compounds with the prospective target, EGFR^WT and EGFR^T790M.     

New thiazol-hydrazono-coumarin hybrids targeting human cervical cancer cells: Synthesis,CDK2 inhibition,QSAR and molecular docking studies

Motivated by the potential anticancer activity of both coumarin and 2-aminothiazole nuclei, a new set of thiazol-2-yl hydrazono-chromen-2-one analogs were efficiently synthesized aiming to obtain novel hybrids with potential cytotoxic activity. MTT assay investigated the significant potency of all the target compounds against the human cervical cancer cell lines (HeLa cells). Cell cycle analysis showed that the representative compound 8a led to cell cycle cessation at G0/G1 phase indicating that CDK2/E1complex could be the plausible biological target for these newly synthesized compounds. Thus, the most active compounds (7c and 8a-c) were tested for their CDK2 inhibitory activity. The biological results revealed their significant CDK2 inhibitory activity with IC₅₀ range of 0.022–1.629 nM. Moreover, RT-PCR gene expression assay showed that compound 8a increased the levels of the nuclear CDK2 regulators P21 and P27 by 2.30 and 5.7 folds, respectively. ELISA tequnique showed also that compound 8a led to remarkable activation of caspases-9 and -3 inducing cell apoptosis. QSAR study showed that the charge distribution and molecular hydrophobicity are the structural features affecting cytotoxic activity in this series. Molecular docking study for the most potent cytotoxic compounds (7c and 8a-c) rationalized their superior CDK2 inhibitory activity through their hydrogen bonding and hydrophobic interactions with the key amino acids in the CDK2 binding site. Pharmacokinetic properties prediction of the most potent compounds showed that the newly synthesized compounds are not only with promising antitumor activity but also possess promising pharmacokinetic properties.     

Design,synthesis and biological evaluation of novel 6-alkenylamides substituted of 4-anilinothieno[2,3-d]pyrimidines as irreversible epidermal growth factor receptor inhibitors

A novel series of 6-alkenylamides of 4-anilinothieno[2,3-d]pyrimidine derivatives was designed, synthesized and evaluated as irreversible inhibitors of the epidermal growth factor receptor (EGFR). Most of the compounds exhibited good potency against EGFR wild type (EGFR wt) and EGFR T790M/L858R. Among these, the half-maximal inhibitory concentration (IC₅₀) values of 17 compounds against EGFR wt were less than 0.020 μM, and those of 12 compounds were less than 0.010 μM. The IC₅₀ values of 10 compounds against EGFR T790M/L858R were less than 0.005 μM. Compounds 8l, 9n, 9o, 9q and 9v almost completely blocked the phosphorylation of EGFR in the A431 cell line at 1 μM. Compounds 8l, 9n, 9o, 9q and 9v blocked the autophosphorylation of EGFR in NCI-H1975 cells at high concentration (1 μM), and compound 8l was confirmed to be an irreversible inhibitor through the dilution method.     

Discovery of novel 2-substituted-4-phenoxypyridine derivatives as potential antitumor agents

A series of 2-substituted-4-phenoxypyridine derivatives were designed, synthesized, and evaluated for their antiproliferative activity against 4 cancer cell lines (A549, HT-29, H460, and U87MG) in vitro. Most compounds showed moderate to excellent potency. Nine tyrosine kinases (c-Met, Flt-3, ALK, VEGFR-2, VEGFR-3, PDGFR-α, PDGFR-β, c-Kit, and EGFR) were used to evaluate the inhibitory activities with the most promising analogue 39, which showed the Flt-3/c-Met IC₅₀ values of 2.18/2.61?nM. Structure-activity relationship studies indicated that n-Pr served as R¹ group showed a higher preference, and stronger mono-EWGs on the phenyl ring (such as R²?=?4-F) was benefited to the potency.     

Discovery of novel 6,7-disubstituted-4-phenoxyquinoline derivatives bearing 5-(aminomethylene)pyrimidine-2,4,6-trione moiety as c-Met kinase inhibitors

A series of novel quinoline derivatives bearing 5-(aminomethylene)pyrimidine-2,4,6-trione moiety were designed, synthesized, and evaluated for their c-Met kinase inhibitory activities and antiproliferative activities against 5 cancer cell lines (HT-29, H460, MKN-45, A549, and U87MG) in vitro. Most compounds showed moderate to excellent potency, with the most promising analogue 45 (c-Met half-maximal inhibitory concentration [IC₅₀] = 1.15 nM) showing high selectivity versus 5 other tyrosine kinases, VEGFR-2, Flt-3, PDGFR-β, c-Kit, and EGFR. Structure–activity relationship studies indicated that electron-donating groups on the phenyl ring at the 3-position of pyrimidine-2,4,6-trione were required to increase the electron density on the 5-(aminomethylene)pyrimidine-2,4,6-trione moiety.     

Design and synthesis of a new generation of substituted purine hydroxamate analogs as histone deacetylase inhibitors

Histone deacetylase inhibitors have been proved to be great potential for the treatment of cancer. Recently, we designed and modified a series of substituted purine hydroxamate analogs as potent HDAC inhibitors based on our previous studies. The target compounds were investigated for their in vitro HDAC inhibitory activities and anti-proliferative activities. Results indicated that these compounds could effectively inhibit HDAC and possess obvious anti-proliferative activity against tumor cells. Promisingly, target compounds 4m and 4n outperformed SAHA in both enzymatic inhibitory activity and cellular anti-proliferative activity assay.     

Quinazoline-1-deoxynojirimycin hybrids as high active dual inhibitors of EGFR and α-glucosidase

A series of novel quinazoline-1-deoxynojirimycin hybrids were designed, synthesized and evaluated for their inhibitory activities against two drug target enzymes, epidermal growth factor receptor (EGFR) tyrosine kinase and α-glucosidase. Some synthesized compounds exhibited significantly inhibitory activities against the tested enzymes. Comparing with reference compounds gefitinib and lapatinib, compounds 7d, 8d, 9b and 9d showed higher inhibitory activities against EGFR (IC₅₀: 1.79–10.71 nM). Meanwhile the inhibitory activities of 7d, 8d and 9c against α-glucosidase (IC₅₀ = 0.14, 0.09 and 0.25 µM, respectively) were obvious higher than that of miglitol (IC₅₀ = 2.43 µM), a clinical using α-glucosidase inhibitor. Interestingly, compound 9d as a dual inhibitor showed high inhibitory activity to EGFR^wt tyrosine kinase (IC₅₀ = 1.79 nM), also to α-glucosidase (IC₅₀ = 0.39 µM). The work could be very useful starting point for developing a new series of enzyme inhibitors targeting EGFR and/or α-glucosidase.     

Synthesis and anticancer activity of novel 4-morpholino-7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidine derivatives bearing chromone moiety

Herein, we designed and synthesized of a novel series of 7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidine derivatives bearing chromone moiety (10a–j, 13a–j). All the compounds were evaluated for the IC₅₀ values against five cancer cell lines (A549, PC-3, MCF-7, Hela and HepG2). Seven of the target compounds exhibited moderate to excellent cytotoxicity. For these compounds, we tested their inhibitory activities against mTOR kinase, and four of them were tested their inhibitory activities against PI3Kα kinase in further. The results indicated that the optimized compound 10j showed excellent inhibitory activity and cytotoxicity against mTOR kinase, PI3Kα kinase and five cancer cell lines with IC₅₀ values of 1.1 μM, 0.92 μM and 8.77–14.3 μM. Structure–activity relationships (SARs) and docking studies indicated that the thiopyrano[4,3-d]pyrimidine scaffolds exerted little effect on antitumor activities of target compounds. Substitutions of chromone moiety at C-6 position with carboxyl were benefit to the antitumor activities.     

Synthesis of potent antitumor and antiviral benzofuran derivatives

A new series of potent antitumor and antiviral benzofuran derivatives was synthesized by the reaction of the furochromone-6-carboxaldehydes 1 and 2 with different heterocyclic amines to yield the benzofuran-5-carbonyl derivatives 4–11. The synthesized compounds 1, 3–11 were tested against twelve different human cancer cell lines and all of the compounds were more potent than the comparative standards. The HIV inhibitory activity of the tested compounds 1, 3–11 showed that they have higher potency than Atevirdine. Moreover, compound 6 was significantly potent with wider therapeutic index. The HIV-1 RT inhibitory activity showed that compounds 10, 11, 3 and 4 were notably potent but with lower therapeutic index than Atevirdine. The HCV NS3-4A protease inhibitor activity of the tested compounds revealed that they have weaker potency and less therapeutic index than VX-950, although compounds 1, 4, 9 and 6, respectively exhibited significant activity.     

Novel quinazoline derivatives bearing various 6-benzamide moieties as highly selective and potent EGFR inhibitors

A series of novel quinazoline derivatives bearing various C-6 benzamide substituents were synthesized and evaluated as EGFR inhibitors, and most showed significant inhibitory potency against EGFR kinase. In particular, compound 6g possessed potent inhibitory activity against EGFR wild-type (IC₅₀?=?5?nM), and strong antiproliferative activity against HCC827 and Ba/F3 (L858R) cell lines. Kinase profiling against a panel of 365 kinases showed that 6g was highly selective for EGFR. Furthermore, 6g showed desirable properties in assays of liver microsome metabolic stability and cytochromes P450 inhibition and preliminary pharmacokinetic study. The overall attractive profile of 6g made it an interesting compound for further development.     

Design,synthesis and anticervical cancer activity of new benzofuran–pyrazol-hydrazono- thiazolidin-4-one hybrids as potential EGFR inhibitors and apoptosis inducing agents

This study represents the synthetic approaches of a new set of 2-(((3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene)hydrazono)-5-(aryl)thiazolidin-4-one derivatives 4–22 aiming to obtain new antiproliferative candidates against human cervix carcinoma cells (Hela) of EGFR PK inhibiting potency. The cancer cells represented promising sensitivity towards the compounds 6, 7, 11, 13, 14, 16, 17 more than or equal to that against the reference drug doxorubicin. In addition, the latter compounds were tested as EGFR protein kinase inhibitors. The results revealed that compound 14 showed more significant EGFR PK inhibitory activity than the reference drug erlotinib (IC50; 0.07, 0.08 µM, respectively). Moreover, cell cycle analysis and apoptosis assay were performed for compound 14 proving its ability to cause G1/S phase arrest and apoptosis in Hela cancer cells, in addition to its activation of the caspases-7 and -3. In addition, derivative 14 increased the expression level of p53 and the ratio of Bax/Bcl-2 which confirmed its mode of action. Molecular docking study of 14 was performed to investigate its binding mode of interaction with EGFR PK in the active site with the aim of rationalizing its promising inhibitory activity. Accordingly, compound 14 might be considered as a promising scaffold anticervical cancer chemotherapeutic and deserves further optimization and in-depth biological studies.