Pd-Catalyzed Direct Modification of an Anti-Alzheimer's Disease Drug: Synthesis and Biological Evaluation of α-Aryl Donepezil Analogues

Light-promoted stereoselective late-stage difunctionalization and anti-tumor activity of oridonin

The late-stage difunctionalization of diterpene oridonin by light-promoted direct oxyamination with various O-benzoylhydroxylamines was carried out to afford C16α-N-C17-OBz-oridonin derivatives (1-25) for the first time. Though as a radical reaction, it features high stereoselectivity to only produce C16α-N-C17-OBz-oridonins. The in vitro antiproliferative activity of these C16α-N-C17-OBz-oridonins against the human breast cancer cell lines (MCF-7) was evaluated by MTT assay, showing that most of the synthesized compounds possessed moderate anticancer activity against MCF-7 cell lines superior or similar to the parent compound oridonin. The derivative 25 with a N-methyl-N-(naphthalen-1-ylmethyl) substitution showed better cytotoxicity against MCF-7 cells (IC50 value of 11.75 μM) than oridonin (IC50 value of 17.95 μM).

Design, synthesis and biological evaluation of 1-aryldonepezil analogues as anti-Alzheimer's disease agents

Aim: To design and synthesize a novel series of 1-aryldonepezil analogues. Materials & methods: The 1-aryldonepezil analogues were synthesized through palladium/PCy3-catalyzed Suzuki reaction and were evaluated for cholinesterase inhibitory activities and neuroprotective effects. In silico docking of the most effective compound was conducted. Results: The 4-tert-butylphenyl analogue exhibited good inhibitory potency against acetylcholinesterase and butyrylcholinesterase and had a favorable neuroprotective effect on H2O2-induced SH-SY5Y cell injury. Conclusion: The 4-tert-butylphenyl derivative is a promising lead compound for anti-Alzheimer's disease drug development.

Palladium-catalyzed synthesis and anti-AD biological activity evaluation of N-aryl-debenzeyldonepezil analogues

A series of novel N-aryl-debenzeyldonepezil derivatives (1-26) were designed and synthesized as cholinesterase inhibitors by the modification of anti-Alzheimer's disease drug donepezil, using Palladium catalyzed Buchwald-Hartwig cross-coupling reaction as a key chemical synthesis strategy. In vitro cholinesterase inhibition studies demonstrated that the majority of synthesized compounds exhibited high selective inhibition of AChE. Among them, analogue 13 possessing a quinoline functional group showed the most potent AChE inhibition effect and significant neuroprotective effect against H2O2-induced injury in SH-SY5Y cells. Furthermore, Compound 13 did not show significant cytotoxicity on SH-SY5Y. These results suggest that 13 is a potential multifunctional active molecule for treating Alzheimer's disease.

Palladium-catalyzed synthesis and acetylcholinesterase inhibitory activity evaluation of 1-arylhuperzine A derivatives

A series of arylated huperzine A (HPA) derivatives (1-24) were efficiently synthesized in good yields (45-88% yields) through the late-stage modification of structurally complex natural anti-Alzheimer's disease (AD) drug huperzine A (HPA), using the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. The acetylcholinesterase (AChE) inhibitory activity of all synthesized compounds was evaluated to screen the potential anti-AD bioactive molecules. The results showed that introducing the aryl groups to C-1 position of HPA resulted in the unsatisfactory AChE inhibitory activity. The present study demonstrably verifies pyridone carbonyl group could be the necessary and unchangeable pharmacophore for maintaining HPA's anti-AChE potency, and provides the helpful information on the further research for developing anti-AD HPA analogues.

Design, Synthesis, and Biological Activity of Donepezil: Aromatic Amine Hybrids as Anti-Alzheimerss Drugs

In this study, benzylpiperidine, the active group of donepezil (DNP), was connected with the neurotransmitter phenylethylamine by square amide, in which the fat chain of phenylethylamine was reduced and the benzene rings were substituted. A series of multifunctional hybrid compounds, including DNP-aniline hybrids (1-8), DNP-benzylamine hybrids (9-14), and DNP-phenylethylamine hybrids (15-21) were obtained and their cholinesterase inhibitory activity and neuroprotection of the SH-SY5Y cell line were determined. Results showed that compound 3 exhibited excellent acetylcholinesterase inhibitory activity with an IC₅₀ value of 4.4 μM, higher than that of positive control DNP and significant neuroprotective effects against H₂O₂-induced oxidative damage in SH-SY5Y cells with 80.11% viability rate at 12.5 μM, much higher than that of the model group (viability rate = 53.1%). The mechanism of action of compound 3 was elucidated by molecular docking, reactive oxygen species (ROS), and immunofluorescence analysis. The results suggest that compound 3 could be further explored as a lead compound for the treatment of Alzheimer's disease. In addition, molecular docking research indicated that the square amide group formed strong interactions with the target protein. Based on the above analysis, we believe that square amide could be an interesting construction unit in anti-AD agents.

Palladium-Catalyzed Synthesis, Acetylcholinesterase Inhibition, and Neuroprotective Activities of N-Aryl Galantamine Analogues

A series of new N-aryl galantamine analogues (5a-5x) were designed and synthesized by modification of galantamine, using Pd-catalyzed Buchwald-Hartwig cross-coupling reaction in good to excellent yields. The cholinesterase inhibitory and neuroprotective activities of N-aryl derivatives of galantamine were evaluated. Among the synthesized compounds, the 4-methoxylpyridine-galantamine derivative (5q) (IC₅₀ = 0.19 μM) exhibited excellent acetylcholinesterase inhibition activity, as well as significant neuroprotective effect against H₂O₂-induced injury in SH-SY5Y cells. Molecular docking, staining, and Western blotting analyses were performed to demonstrate the mechanism of action of 5q. Derivative 5q would be a promising multifunctional lead compound for the treatment of Alzheimer's disease.

Palladium-Catalyzed Direct Synthesis and Insecticidal Activity of Arylmatrine Derivatives

Pd(OAc)₂/NiXantphos efficiently catalyzed the direct arylation at the C-14 position of matrine, leading to 38 arylmatrine derivatives (1a-19a and 1b-19b) in good yields. Most of these matrine analogues showed enhanced insecticidal effects superior to the parent compound matrine. Among them, the 3,5-diphenylbenzene analogue (8b) exhibited the most potent in vivo antifeedant activity (EC₅₀ = 0.19 mg/mL) against Spodoptera exigua (Hübner), with approximately 25-fold more activity than matrine, for which the preliminary mechanism of action was verified through enzyme inhibition activities and molecular docking. Compound 8b as well displayed in vitro antiproliferation activity on Sf9 insect cells (IC₅₀ = 8.1 μM), and its apoptotic induction effect was illustrated by morphological observation and DNA fragment analysis. Overall, the above results provide further information on the potential of arylmatrine-type lead compounds for the prevention and control of insect pests.