Application of Sequential Palladium Catalysis for the Discovery of Janus Kinase Inhibitors in the Benzo[ c]pyrrolo[2,3- h][1,6]naphthyridin-5-one (BPN) Series

Discovery of a potent anticancer agent against pancreatic ductal adenocarcinoma targeting FAK with DFG-out state and JAK/Aurora kinases

Pancreatic ductal adenocarcinoma (PDAC) is a clinically challenging cancer because of the difficulty in diagnosis and its resistance to chemotherapy. Focal adhesion kinase (FAK) is found overexpressed in PDAC, and targeting FAK has been proved to impede the progress of PDAC. However, most of FAK inhibitors were reported to bind with FAK in a DFG-in conformation, leading to a limited anti-tumor effect in clinical studies. Herein, to develop FAK inhibitors targeting the inactive DFG-out conformation, a series of large aromatic rings were selected to improve the interaction with Phe565 of the DFG motif. Compound 26 was designed to effectively inhibit FAK and the proliferation of PANC-1 cells with IC50 of 50.94 nM and 0.15 μM, respectively. Besides, compound 26 was proved to strongly suppress the proliferation, colony formation, migration, and invasion in FAK-overexpressing PDAC cells. This inhibitor was confirmed to induce the apoptosis and G2/M arrest in PANC-1 cells through the suppression of FAK/PI3K/Akt signal pathway. Meanwhile, compound 26 was found to simultaneously inhibit FAK with DFG-out conformation and JAK3/Aurora B (IC50 of 9.99 nM and 0.49 nM, respectively). In vivo, compound 26 effectively inhibited the tumorigenesis and metastasis of PDAC with desirable biosafety. Overall, these results suggested that compound 26 was a promising candidate for the treatment of PDAC.

Synthetic Routes to 2-aryl-1H-pyrrolo[2,3-b]pyridin-4-amines: Cross-Coupling and Challenges in SEM-Deprotection

7-Azaindoles are compounds of considerable medicinal interest. During development of the structure-activity relationship for inhibitors of the colony stimulated factor 1 receptor tyrosine kinase (CSF1R), a specific 2-aryl-1H-pyrrolo[2,3-b]pyridin-4-amine was needed. Two different synthetic strategies were evaluated, in which the order of the key C-C and C-N cross-coupling steps differed. The best route relied on a chemoselective Suzuki-Miyaura cross-coupling at C-2 on a 2-iodo-4-chloropyrrolopyridine intermediate, and subsequently a Buchwald-Hartwig amination with a secondary amine at C-4. Masking of hydroxyl and pyrroles proved essential to succeed with the latter transformation. The final trimethylsilylethoxymethyl (SEM) deprotection step was challenging, as release of formaldehyde gave rise to different side products, most interestingly a tricyclic eight-membered 7-azaindole. The target 2-aryl-1H-pyrrolo[2,3-b]pyridin-4-amine (compound 3c) proved to be 20-fold less potent than the reference inhibitor, confirming the importance of the N-3 in the pyrrolopyrimidine parent compound for efficient CSF1R inhibition.

Site-Selective Synthesis of Antitumor C5-Aminated Indoles via Neighboring Aldehyde Group Assisted Catellani Reaction

A palladium/norbornene (NBE) cooperative catalytic system was developed to access C5-aminated indoles, starting from readily available C4-idonated indoles. Good yields and exclusive site selectivity were achieved for a broad substrate scope, including drug molecule core architectures. Control experiments found that both aldehyde on the C3 position and sulfonyl protecting group on the N1 position were vital for the transformation. Preliminary bioactivity evaluation identified a promising leading compound 3af with potent antitumor proliferative activity against several cancer cells.

The Hitchhiker's Guide to Deep Learning Driven Generative Chemistry

This microperspective covers the most recent research outcomes of artificial intelligence (AI) generated molecular structures from the point of view of the medicinal chemist. The main focus is on studies that include synthesis and experimental in vitro validation in biochemical assays of the generated molecular structures, where we analyze the reported structures' relevance in modern medicinal chemistry and their novelty. The authors believe that this review would be appreciated by medicinal chemistry and AI-driven drug design (AIDD) communities and can be adopted as a comprehensive approach for qualifying different research outcomes in AIDD.

Synthesis and Anticancer Properties of Functionalized 1,6-Naphthyridines

The burgeoning interest in synthesis and biological applications of 1,6-naphthyridines reflects the importance of 1,6-naphthyridines in the synthetic as well as medicinal chemistry fields. Specially, 1,6-naphthyridines are pharmacologically active, with variety of applications such as anticancer, anti-human immunodeficiency virus (HIV), anti-microbial, analgesic, anti-inflammatory and anti-oxidant activities. Although collective recent synthetic developments have paved a path to a wide range of functionalized 1,6-naphthyridines, a complete correlation of synthesis with biological activity remains elusive. The current review focuses on recent synthetic developments from the last decade and a thorough study of the anticancer activity of 1,6-naphthyridines on different cancer cell lines. Anticancer activity has been correlated to 1,6-naphthyridines using the literature on the structure-activity relationship (SAR) along with molecular modeling studies. Exceptionally, at the end of this review, the utility of 1,6-naphthyridines displaying activities other than anticancer has also been included as a glimmering extension.

Design, synthesis, biological activity evaluation of 3-(4-phenyl-1H-imidazol-2-yl)-1H-pyrazole derivatives as potent JAK 2/3 and aurora A/B kinases multi-targeted inhibitors

In this study, a series of 3-(4-phenyl-1H-imidazol-2-yl)-1H-pyrazole derivatives were designed, synthesized, and evaluated for their biological activities. Upon performing kinase assays, most of the compounds exhibited potent inhibition against JAK2/3 and Aurora A/B with the IC₅₀ values ranging from 0.008 to 2.52 μM. Among these derivatives, compound 10e expressed the most moderate inhibiting activities against all the four kinases with the IC₅₀ values of 0.166 μM (JAK2), 0.057 μM (JAK3), 0.939 μM (Aurora A), and 0.583 μM (Aurora B), respectively. Moreover, most of the derived compounds exhibited potent cytotoxicity against human chronic myeloid leukemia cells K562 and human colon cancer cells HCT116, while compound 10e expressed antiproliferative activities against K562 (IC₅₀₌6.726  μM). According to western blot analysis, compound 10e down-regulated the phosphorylation of STAT3, STAT5, Aurora A, and Aurora B in a dose-dependent manner in K562 and HCT116 cells. Cell cycle analysis revealed that compound 10e inhibited the proliferation of cells by inducing cell cycle arrest in the G2 phase. The molecular modeling suggested that compound 10e could maintain a binding mode similar to the binding mode of AT9832, a common JAK 2/3 and Aurora A/B kinases multi-target kinase inhibitor. Therefore, compound 10e might be a potential agent for cancer therapy deserving further research.

Palladium-catalyzed remote C-H functionalization of 2-aminopyrimidines

A straightforward strategy was developed for the arylation and olefination at the C5-position of the N-(alkyl)pyrimidin-2-amine core with readily available aryl halides and alkenes, respectively. This approach was highly regioselective, and the transformation was achieved based on two different (Pd(ii)/Pd(iv)) and (Pd(0)/Pd(ii)) catalytic cycles.

Janus kinases (JAKs): The efficient therapeutic targets for autoimmune diseases and myeloproliferative disorders

The Janus kinases or JAKs are a family of intracellular tyrosine kinases that play an essential role in the signaling of numerous cytokines that have been implicated in the pathogenesis of autoimmune diseases and myeloproliferative disorders. JAKs are activated upon ligand induced receptor homo- or heterodimerization, which results in the immediate phosphorylation of tyrosine residues and the phosphotyrosines then serve as docking sites for cytoplasmic signal transducer and activator of transcription (STAT) proteins which become phosphorylated by the JAKs upon recruitment to the receptor complex. The phosphorylated STAT proteins dimerize and travel to the cellular nucleus, where they act as transcription factors. Interfering in the JAK-STAT pathway has yielded the only approved small molecule kinase inhibitors for immunological indications. Numerous medicinal chemistry studies are currently aimed at the design of novel and potent inhibitors for JAKs. Additionally, whether the second-generation inhibitors which possessed selectivity for JAKs are more efficient are under research. This Perspective summarizes the progress in the discovery and development of JAKs inhibitors, including the potential binding site and approaches for identifying small-molecule inhibitors, as well as future therapeutic perspectives in autoimmune diseases and myeloproliferative disorders are also put forward in order to provide reference and rational for the drug discovery of novel and potent JAKs inhibitors.