Design, synthesis, biological evaluation, and in silico studies of novel pyridopyridine derivatives as anticancer candidates targeting FMS kinase.

Design and synthesis of novel 4-carboxamidopyrido[3,2-b]pyridine derivatives as novel rigid analogues of sorafenib are reported herein. The target compounds showed potent antiproliferative activities against a panel of NCI-60 cancer cell lines as well as hepatocellular carcinoma cell line. Compounds 8g and 9f were among the most promising derivatives in terms of effectiveness and safety. Therefore, they were further examined to demonstrate their ability to induce apoptosis and alter cell cycle progression in hepatocellular carcinoma cells. The most potent compounds were tested against a panel of kinases that indicated their selectivity against FMS kinase. Compounds 8g and 8h showed the most potent activities against FMS kinase with IC50 values of 21.5 and 73.9 nM, respectively. The two compounds were also tested in NanoBRET assay to investigate their ability to inhibit FMS kinase in cells (IC50 = 563 nM (8g) and 1347 nM (8h) vs. IC50 = 1654 nM for sorafenib). Furthermore, compounds 8g and 8h possess potent inhibitory activities against macrophages when investigated in bone marrow-derived macrophages (BMDM) assay (IC50 = 56 nM and 167 nM, respectively, 164 nM for sorafenib). The safety and selectivity of these compounds were confirmed when tested against normal cell lines. Their safety profile was further confirmed using hERG assay. In silico studies were carried out to investigate their binding modes in the active site of FMS kinase, and to develop a QSAR model for these new motifs.

Design, synthesis, and biological evaluation of a new series of pyrazole derivatives: Discovery of potent and selective JNK3 kinase inhibitors.

The design, synthesis, and biological activities of a new series of pyrazole derivatives are reported. The target compounds 1a-1w were initially investigated against NCI-60 cancer cell lines. Compounds 1f, 1h, 1k, and 1v exerted the highest anti-proliferative activity over the studied panel of cancer cell lines. Compound 1f showed the most potent activity, and it is more potent than sorafenib in 29 cancer cell lines of different types and more potent than SP600125 against almost all the tested cancer cell lines. It also exerted sub-micromolar IC50 values (0.54-0.98 µM) against nine cell lines. Moreover, the 23 target compounds were tested against Hep3B and HepG2 hepatocellular carcinoma cell lines, of which compounds 1b, 1c, and 1h showed the strongest anti-proliferative activity. The most potent anticancer compounds (1b, 1c, 1f, and 1h) demonstrated a high selectivity towards cancer cells vis-à-vis normal cells. Compounds1f and 1h induced apoptosis and mild necrosis upon testing against RPMI-8226 leukemia cells. Kinase profiling of this series led to the discovery of two potent and selective JNK3 inhibitors, compounds 1c and 1f with an IC50 values of 99.0 and 97.4 nM, respectively. Both compounds showed a good inhibitory effect against JNK3 kinase in the whole-cell NanoBRET assay. This finding was further supported through molecular modeling studies with the JNK3 binding site. Moreover, compounds 1c and 1f demonstrated a very weak activity against CYP 2D6, CYP 3A4, and hERG ion channels.

Visible Light-Mediated [2 + 2] Cycloaddition Reactions of 1,4-Quinones and Terminal Alkynes.

A single-step synthesis of 4-hydroxy-functionalized bi-aryl and aryl/alkyl ketones via oxidative coupling of terminal alkynes with benzoquinones is reported. Furthermore, with naphthoquinones, owing to the cross-resonance of carbonyl with the aromatic ring, alkene-alkyne cycloaddition is more favored to give four-membered carbocyclic adducts, thereby precluding the requirement of preactivated alkynes.

Carbon-Carbon and Carbon-Heteroatom Bond Formation Reactions Using Unsaturated Carbon Compounds.

The carbon-carbon and carbon-heteroatom bond formation reactions are considered as a fundamental tool in synthetic organic chemistry. They have been effectively utilized in the synthesis of medicinally significant molecules, agrochemicals and valuable compounds in material sciences. This has been primarily enabled by highly efficient protocols arising from divergent mechanistic pathways. In this personal account, we aim to discuss some recent advances in carbon-carbon or carbon-heteroatom bond formation reactions to which our group has actively contributed. More specifically, this record focuses on the use of unsaturated carbon compounds for the construction of C-C and C-X bonds.

Acyl Radicals from Terminal Alkynes: Photoredox-Catalyzed Acylation of Heteroarenes.

A photoredox-mediated acylation reaction of electron deficient heteroarenes with terminal alkynes is reported. The method relies on oxidative cleavage of phenylacetylenes for generation of acyl radicals as a key enabling feature. The reaction is regioselective with broad substrate scope. Quantum yield investigations support a radical chain mechanism.

Radical-radical cross coupling reactions of photo-excited fluorenones.

Radical-radical cross coupling reactions of photoexcited 9-fluorenones have been accomplished for the first time, leading to the synthesis of 9-alkyl, pyrollidinyl and spiro-THF derivatives of 9-fluorenones. The method also reveals, for the first time, the behaviour of ketyl radicals in decarboxyaltive alkylation and ring expansion reactions.