Synthesis and bioactivity of novel amino-pyrazolopyridines

Biological evaluation, docking studies, and in silico ADME prediction of some pyrimidine and pyridine derivatives as potential EGFRWT and EGFRT790M inhibitors

Herein, a set of pyridine and pyrimidine derivatives were assessed for their impact on the cell cycle and apoptosis. Human breast cancer (MCF7), hepatocellular carcinoma (HEPG2), larynx cancer (HEP2), lung cancer (H460), colon cancers (HCT116 and Caco2), and hypopharyngeal cancer (FADU), and normal Vero cell lines were used. Compounds 8 and 14 displayed outstanding effects on the investigated cell lines and were further tested for their antioxidant activity in MCF7, H460, FADU, HEP2, HEPG2, HCT116, Caco2, and Vero cells by measuring superoxide dismutase (SOD), malondialdehyde content (MDA), reduced glutathione (GSH), and nitric oxide (NO) content. Besides, Annexin V-FITC apoptosis detection and cell cycle DNA index using the HEPG-2 cell line were established on both compounds as well. Furthermore, compounds 8 and 14 were assessed for their EGFR kinase (Wild and T790M) inhibitory activities, revealing eligible potential. Additionally, molecular docking, ADME, and SAR studies were carried out for the investigated candidates.

Design, synthesis, theoretical study, antioxidant, and anticholinesterase activities of new pyrazolo-fused phenanthrolines

Pyrazole-fused phenanthroline compounds were obtained through several synthetic routes. NMR, HRMS, and IR techniques were used to characterize and confirm the chemical structures. Crystal structures were obtained from compounds 3a, 5b, 5j, 5k, and 5n and analyzed using X-ray diffraction. Compounds were evaluated as acetyl (AChE) and butyrylcholinesterase (BChE) inhibitors, and the results showed a moderate activity. Compound 5c presented the best activity against AChE (IC50 = 53.29 μM) and compound 5l against BChE enzyme (IC50 = 119.3 μM). Furthermore, the ability of the synthetic compounds to scavenge cationic radicals DPPH and ABTS was evaluated. Compound 5e (EC50 = 26.71 μg mL-1) presented the best results in the DPPH assay, and compounds 5e, 5f and 5g (EC50 = 11.51, 3.10 and <3 μg mL-1, respectively) showed better ABTS cationic radical scavenging results. Finally, in silico analyses indicated that 71% of the compounds show good oral availability and are within the ranges established by the Lipinski criteria.

Synthesis of Diversified Pyrazolo[3,4-b]pyridine Frameworks from 5-Aminopyrazoles and Alkynyl Aldehydes via Switchable C≡C Bond Activation Approaches

A cascade 6-endo-dig cyclization reaction was developed for the switchable synthesis of halogen and non-halogen-functionalized pyrazolo[3,4-b]pyridines from 5-aminopyrazoles and alkynyl aldehydes via C≡C bond activation with silver, iodine, or NBS. In addition to its wide substrate scope, the reaction showed good functional group tolerance as well as excellent regional selectivity. This new protocol manipulated three natural products, and the arylation, alkynylation, alkenylation, and selenization of iodine-functionalized products. These reactions demonstrated the potential applications of this new method.

Nicotinonitrile-derived apoptotic inducers: Design, synthesis, X-ray crystal structure and Pim kinase inhibition

Although a plethora of targeted anticancer small molecule drugs became available, the low response rate and drug resistance imply the continuous need for expanding the anticancer chemical space. In this study, a novel series of nicotinonitrile derivatives was designed, synthesized and evaluated for cytotoxic activities in HepG2 and MCF-7 cells. All derivatives showed high to moderate cytotoxic activity against both cell lines, with cell-type and chemotype-dependent cytotoxic potential. The normal HEK-293 T cells were ca. 50-fold less susceptible to the cytotoxic effect of the inhibitors. The in vitro enzyme inhibitory activity of selected active cytotoxic derivatives 8c, 8e, 9a, 9e and 12 showed that they have sub- to one digit micromolar 50 % inhibitory concentration (IC₅₀) against the three Pim kinase isoforms, with 8e being the most potent (IC₅₀ ≤ 0.28 μM against three Pim kinases), comparable to the pan kinase inhibitor, Staurosporine. In HepG2, 8e induced cell cycle arrest at the G2/M phase. Apoptotic mechanistic studies with 8c and 8e in HepG2 cells, indicated a significant upregulation in both P53 and caspase-3 relative gene expression, as well as increased Bax/Bcl-2 protein expression level. Further, docking studies combined with molecular dynamic simulation showed a stable complex with high binding affinity of 8e to Pim-1 kinase; exploiting a negative electrostatic potential surface interaction with the added dimethyl amino group in the new compounds. Moreover, in silico ADME profile prediction indicated that all compounds are orally bioavailable and most of them can penetrate the blood-brain barrier. This study presents novel nicotinonitrile derivatives as auspicious hits for further optimization as antiproliferative agents against liver cancer cells and promising pan Pim kinase inhibitors at submicromolar concentrations.

Organocatalyzed Modular Synthesis of Polycyclic Dihydropyridines and Pyridines through Sulfamate Linchpin

The cascade annulation between alkylidene malononitriles and cyclic sulfamidate imines has been controlled by leveraging the sulfamate functionality under organocatalysis, which allows selective access to polycyclic and densely functionalized dihydropyridines and pyridines in high yields. The protocol is scalable and shows broad substrate scope. The products were also engaged in the preparation of tetracyclic pyridopyrimidines, showcasing the synthetic versatility.

1H-Pyrazolo[3,4-b]pyridines: Synthesis and Biomedical Applications

Pyrazolo[3,4-b]pyridines are a group of heterocyclic compounds presenting two possible tautomeric forms: the 1H- and 2H-isomers. More than 300,000 1H-pyrazolo[3,4-b]pyridines have been described which are included in more than 5500 references (2400 patents) up to date. This review will cover the analysis of the diversity of the substituents present at positions N1, C3, C4, C5, and C6, the synthetic methods used for their synthesis, starting from both a preformed pyrazole or pyridine, and the biomedical applications of such compounds.

Recent Advances in the Development of Pyrazolopyridines as Anticancer Agents

Cancer, especially malignant tumor, is a serious threat to people's life and health. It is recognized as an enormous challenge in the 21st century. Continuous efforts are needed to overcome this problem. Pyrazolopyridine nucleus, similar in structure to purine, shows a variety of biological activities, which is mainly attributed to the antagonistic nature towards the natural purines in many biological processes. This has aroused enormous attention for many researchers. At present, a large number of new chemical entities containing pyrazolopyridine nucleus have been found as anticancer agents. In this review we summarize novel pyrazolopyridine-containing derivatives with biological activities. Furthermore, we outline the relationships between the structures of variously modified pyrazolopyridines and their anticancer activity.

Recent Progress on Anticancer Agents Incorporating Pyrazole Scaffold

The search of new anticancer agents is considered as a dynamic field of medicinal chemistry. In recent years, the synthesis of compounds with anticancer potential has increased and a large number of structurally varied compounds displaying potent anticancer activities have been published. Pyrazole is an important biologically active scaffold that possessed nearly all types of biological activities. The aim of this review is to collate literature work reported by researchers to provide an overview on in vivo and in vitro anticancer activities of pyrazole based derivatives among the diverse biological activities displayed by them and also presents recent efforts made on this heterocyclic moiety regarding anticancer activities. This review has been driven from the increasing number of publications, on this issue, which have been reported in the literature since the ending of the 20th century (from 1995-to date).

Antiviral Drug Discovery and Development for Mayaro Fever - What do we have so far?

Tropical infectious diseases cause millions of deaths every year in developing countries, with about half of the world population living at risk. Mayaro virus (MAYV) is an emerging arbovirus that causes Mayaro fever, which is characterized by fever, headache, diarrhea, arthralgia, and rash. These symptoms can be clinically indistinguishable from other arboviruses, such as Dengue, Zika, and Chikungunya, which makes the diagnosis and treatment of the disease more difficult. Though, the Mayaro virus is a potential candidate to cause large-scale epidemics on the scale of ZIKV and CHIKV. Despite this, there is no licensed vaccine or antiviral for the treatment of Mayaro fever and most arboviruses, so the design and development of candidates for antiviral drugs are urgently needed. In this context, this mini-review aims to provide an overview of studies of anti-MAYV derivatives and highlight the importance of the discovery and development of promising drug candidates for Mayaro fever.

Molecular diversity of the cyclization reaction of 3-methyleneoxindoles with 2-(3,4-dihydronaphthalen-1(2H)-ylidene)malononitriles

The cyclization reaction of 3-methyleneoxindoles with 2-(3,4-dihydronaphthalen-1(2H)-ylidene)malononitrile in ethanol in the presence of DBU at room temperature afforded functionalized 3′-iminospiro[indoline-3,2′-phenanthrenes] in good yields.

Base-mediated synthesis of highly functionalized 2-aminonicotinonitriles from α-keto vinyl azides and α,α-dicyanoalkenes

A novel access to highly functionalized 2-aminonicotinonitriles via efficient annulations of α-keto vinyl azides and α,α-dicyanoalkenes is described.

The crystal structure of 1,5-dibenzyl-1H-pyrazolo[3,4-d]pyrimidine-4(5H)-thione

In the title compound, C₁₉H₁₆N₄S, the pyrazolo­[3,4-d]pyrimidine ring is close to being planar, with the greatest deviation from the mean plane being 0.023 (2) Å for the C atom bearing the thione S atom. The two phenyl rings are nearly perpendicular to the fused ring system [dihedral angles = 71.4 (2) and 78.1 (2)°], but are oriented in opposite directions; the dihedral angle between the phenyl rings is 32.22 (16)°. In the crystal, linear supra­molecular chains along [101] are sustained by C—H⋯S inter­actions.