Identification of 4-Phenoxyquinoline Based Inhibitors for L1196M Mutant of Anaplastic Lymphoma Kinase by Structure-Based Design

From (Tool)Bench to Bedside: The Potential of Necroptosis Inhibitors

Necroptosis is a regulated caspase-independent form of necrotic cell death that results in an inflammatory phenotype. This process contributes profoundly to the pathophysiology of numerous neurodegenerative, cardiovascular, infectious, malignant, and inflammatory diseases. Receptor-interacting protein kinase 1 (RIPK1), RIPK3, and the mixed lineage kinase domain-like protein (MLKL) pseudokinase have been identified as the key components of necroptosis signaling and are the most promising targets for therapeutic intervention. Here, we review recent developments in the field of small-molecule inhibitors of necroptosis signaling, provide guidelines for their use as chemical probes to study necroptosis, and assess the therapeutic challenges and opportunities of such inhibitors in the treatment of a range of clinical indications.

Synthesis of Palladium-Catalysed C-C Bond Forming 5-Chloro Quinolines via Suzuki-Miyaura Coupling; Anti-Pancreatic Cancer Screening on PANC-1 Cell Lines

Pancreatic cancer is the most severe among other cancers due to its late detection and less chance of survivability. Heterocycles are proven ring systems in the treatment of various cancers and this is due to the presence of two biodynamic molecules combined, which have a greater synergistic efficacy in many anticancer drugs. Quinoline and pyridine ring systems are brought together to obtain greater potency and this is achieved by coupling both using Pd-catalyst, and in the present investigation, Suzuki-Miyaura coupling (SMC) reactions are adopted to generate potent molecular entities. Pancreatic cancer is difficult to treat due to overexpression of the VEGFR2 protein. VEGFR2 is targeted to design the molecules of quinoline-coupled pyridine moieties and is docked to evaluate the protein-ligand interaction at the binding site. The binding affinity of conjugates revealed the potency and capability of ligands to inhibit the VEGFR2 pathway. The in-silico ADMET properties determined their inherent pharmacokinetic feasibility. The synthesized conjugates have been evaluated by MTT assay against the human pancreatic cancer cell lines (PANC-1). Among the series, compounds 5d, 5e, and 5h exhibited a greater inhibitory activity against the cell lines with an IC₅₀ value of 82.32±1.38, 54.74±1.18 and 80.35±1.68 μM. In the present exploration, 5e exhibited greater inhibitory activity and it could be a promising lead for the development of new chemotherapeutics against pancreatic cancer.

Fragment-based discovery of novel phenyltriazolyl derivatives as allosteric type-I1/2 ALK inhibitors with promising antitumor effects

Based on the high-throughput screening hit BY-1, a series of phenyltriazolyl derivatives were developed. Satisfyingly, most compounds were detected moderate to excellent antitumor effects against Karpas299 and H2228 cells. Among them, 12k bearing 4‑hydroxypiperidinyl group exhibited the optimal activities against tested cells with IC₅₀ values of 51 nM and 175 nM, as well as promising inhibitory effects on ALK^WT (3.7 nM) and ALK^L1196M (6.8 nM). Unlike the conventional type-I ALK inhibitors, molecular models identified 12k as an allosteric type-I^1/2 inhibitor by forming key interactions in both the ATP binding region and the hydrophobic back pocket of ALK. Intriguingly, 12k could dose-dependently induce apoptosis on H2228 cell and inhibit colony formation and tumor cell migration. Taken together, the rationalization of 12k may shed new light on the identification of novel allosteric type-I^1/2 ALK inhibitors.

Novel 7-Chloro-(4-thioalkylquinoline) Derivatives: Synthesis and Antiproliferative Activity through Inducing Apoptosis and DNA/RNA Damage

A series of 78 synthetic 7-chloro-(4-thioalkylquinoline) derivatives were investigated for cytotoxic activity against eight human cancer as well as 4 non-tumor cell lines. The results showed, with some exceptions, that sulfanyl 5-40 and sulfinyl 41-62 derivatives exhibited lower cytotoxicity for cancer cell lines than those of well-described sulfonyl N-oxide derivatives 63-82. As for compound 81, the most pronounced selectivity (compared against BJ and MRC-5 cells) was observed for human cancer cells from HCT116 (human colorectal cancer with wild-type p53) and HCT116p53-/- (human colorectal cancer with deleted p53), as well as leukemia cell lines (CCRF-CEM, CEM-DNR, K562, and K562-TAX), lung (A549), and osteosarcoma cells (U2OS). A good selectivity was also detected for compounds 73 and 74 for leukemic and colorectal (with and without p53 deletion) cancer cells (compared to MRC-5). At higher concentrations (5 × IC₅₀) against the CCRF-CEM cancer cell line, we observe the accumulation of the cells in the G0/G1 cell phase, inhibition of DNA and RNA synthesis, and induction of apoptosis. In addition, X-ray data for compound 15 is being reported. These results provide useful scientific data for the development of 4-thioalkylquinoline derivatives as a new class of anticancer candidates.

Quinoline-based Compounds with Potential Activity against Drugresistant Cancers

Drug resistance is the major cause of the failure of cancer chemotherapy, so one of the most important features in developing effective cancer therapeutic strategies is to overcome drug resistance. Quinoline moiety has become one of the most privileged structural motifs in anticancer agent discovery since its derivatives possess potent activity against various cancers including drug-resistant cancers. Several quinoline-based compounds which are represented by Anlotinib, Bosutinib, Lenvatinib, and Neratinib have already been applied in clinical practice to fight against cancers, so quinoline-based compounds are potential anticancer agents. The present short review article provides an overview of the recent advances of quinoline-based compounds with potential activity against drug-resistant cancers. The structure-activity relationship and mechanisms of action are also discussed.

C-H Bond Arylation of Pyrazoles at the β-Position: General Conditions and Computational Elucidation for a High Regioselectivity

Direct arylation of most five-membered ring heterocycles are generally easily accessible and strongly favored at the α-position using classical palladium-catalysis. Conversely, regioselective functionalization of such heterocycles at the concurrent β-position remains currently very challenging. Herein, we report general conditions for regioselective direct arylation at the β-position of pyrazoles, while C-H α-position is free. By using aryl bromides as the aryl source and a judicious choice of solvent, the arylation reaction of variously N-substituted pyrazoles simply proceeds via β-C-H bond functionalization. The β-regioselectivity is promoted by a ligand-free palladium catalyst and a simple base without oxidant or further additive, and tolerates a variety of substituents on the bromoarene. DFT calculations revealed that a protic solvent such as 2-ethoxyethan-1-ol significantly enhances the acidity of the proton at β-position of the pyrazoles and thus favors this direct β-C-H bond arylation. This selective pyrazoles β-C-H bond arylation was successfully applied for the straightforward building of π-extended poly(hetero)aromatic structures via further Pd-catalyzed combined α-C-H intermolecular and intramolecular C-H bond arylation in an overall highly atom-economical process.

Synthesis and antimalarial and anticancer evaluation of 7-chlorquinoline-4-thiazoleacetic derivatives containing aryl hydrazide moieties

Twelve 7-chloroquinoline derivatives were designed and synthesized using the principle of molecular hybridization through the coupling of 2-[2-(7-chloroquinolin-4-ylthio)-4-methylthiazol-5-yl]acetic acid 1 with various benzoyl hydrazines 2a-l. The synthetic compounds were tested as antimalarials. Some of them showed an efficient in vitro activity as inhibitors of β-hematin formation and an in vivo activity in a murine model, resulting in compounds 8 and 9 as the most active ones with IC₅₀ values of 0.65 ± 0.09 and 0.64 ± 0.16 µM, respectively. The effects of the compounds on the cell viability, cell cycle, and apoptosis induction of A549 and MCF-7 cancer cell lines were also examined. Our data showed that compounds 6 and 12 were the most active agents, decreasing the cell viability of MCF-7 cells with IC₅₀ values of 15.41 and 12.99 µM, respectively. None of the compounds analyzed significantly affected the viability of peripheral blood mononuclear cells. Also, significant induction of apoptosis was observed when both cancer cell lines were incubated with compounds 6 and 12. In MCF-7 cells, treatment with these compounds led to cell cycle arrest in the G0/G1 phase. The results obtained suggest that these structures may be useful in developing new therapies for malaria and cancer treatment.

Regioselective C-H Functionalization of Heteroarene N-Oxides Enabled by a Traceless Nucleophile

Although N-alkenoxyheteroarenium salts have been widely used as umpoled synthons with nucleophilic (hetero)arenes, the use of electron-poor heteroarenes has remained unexplored. To overcome the inherent electron deficiency of quinolinium salts, a traceless nucleophile-triggered strategy was designed, wherein the quinolinium segment is converted into a dearomatized intermediate, thereby allowing simultaneous C8-functionalization of quinolines at room temperature. Experimental and computational studies support the traceless operation of a nucleophile, which enables the previously inaccessible transformation of N-alkenoxyheteroarenium salts. Remarkably, the generality of this strategy has been further demonstrated by broad applications in the regioselective C-H functionalization of other electron-deficient heteroarenes such as phenanthridine, isoquinoline, and pyridine N-oxides, offering a practical tool for the late-stage functionalization of complex biorelevant molecules.

Synthesis and biological activity of 2-[2-(7-chloroquinolin-4-ylthio)-4-methylthiazol-5-yl]-N-phenylacetamide derivatives as antimalarial and cytotoxic agents

A novel series of 2-[2-(7-chloroquinolin-4-ylthio)-4-methylthiazol-5-yl]- N-phenylacetamide derivatives is synthesized via substitution with 2-mercapto-4-methyl-5-thiazoleacetic acid at position 4 of 4,7-dichloroquinoline to obtain an intermediate acetic acid derivative. The chemical behavior of these reactants was investigated using different reaction conditions to optimize the nucleophilic substitution at position 4. The final compounds are prepared using a modified version of the Steglich esterification reaction between the acetic acid intermediate 3 and different anilines. The structures are confirmed by infrared, 1H, 13C, distortionless enhancement by polarization transfer 135°, Correlated Spectroscopy, heteronuclear correlation spectroscopy and (Long range HETCOR using three BIRD pulses) FLOCK-NMR spectral studies, and by elemental analysis. The synthesized compounds are tested in vitro and in vivo for their potential antimalarial and anticancer activities, with derivative 11 being the most promising candidate.

Discovery of fluorescent 3-heteroarylcoumarin derivatives as novel inhibitors of anaplastic lymphoma kinase

Coumarin-based ALK inhibitors were identified as a new template for the development of novel fluorescent ALK inhibitors, which can be tracked using microscopy techniques.

Fragment-to-Lead Medicinal Chemistry Publications in 2017

This Miniperspective is the third in a series reviewing fragment-to-lead publications from a given year. Following our reviews for 2015 and 2016, this Miniperspective provides tabulated summaries of relevant articles published in 2017 along with some general observations. In addition, we discuss insights obtained from analysis of the combined data set of 85 examples from all three years of publications.