Rhodium–Catalyzed Direct Arylation of Furopyridine: Synthesis and the Cardiac Effects of Dictamnine Derivatives

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.

Furoquinoline Alkaloids: Insights into Chemistry, Occurrence, and Biological Properties

Furoquinoline alkaloids exhibit a diverse range of effects, making them potential candidates for medicinal applications. Several compounds within this group have demonstrated antimicrobial and antiprotozoal properties. Of great interest is their potential as acetylcholinesterase inhibitors and anti-inflammatory agents in neurodegenerative diseases. The promising biological properties of furoquinoline alkaloids have motivated extensive research in this field. As a result, new compounds have been isolated from this group of secondary metabolites, and numerous pharmacological studies have been conducted to investigate their activity. It is crucial to understand the mechanisms of action of furoquinoline alkaloids due to their potential toxicity. Further research is required to elucidate their mechanisms of action and metabolism. Additionally, the exploration of derivative compounds holds significant potential in enhancing their pharmacological benefits. In vitro plant cultures offer an alternative approach to obtaining alkaloids from plant material, presenting a promising avenue for future investigations.

Metabolite Profiling of Talatisamine in Heart Tissue After Oral Administration and Analysis of Cardiac Bioactivities

The lateral roots of the Aconitum carmichaelii ("Fuzi") have been used for centuries as a cardiotonic in China. The diterpenoid alkaloid talatisamine (TA) is a major bioactive component of Fuzi, but the identity and bioactivities of the TA metabolites have not been examined in detail. In this study, metabolite profiling of TA was performed in rat heart by UPLC-MS following oral administration. Metabolites were identified by comparing protonated molecules, fragmentation patterns, and chromatographic behaviors with those of standard compounds. Metabolites of TA were then prepared and tested for cardiotonic activity on isolated frog hearts. The metabolite cammaconine, a C₁₉ diterpenoid alkaloid with a hydroxyl group at C-18, exhibited substantial cardiotonic activity during frog heart perfusion. To further investigate the structure-cardiac effect relationships, a series of C₁₉-diterpenoid alkaloids with 18-OH were prepared. Eight tested compounds (5: -12: ) demonstrated measurable cardioactivity, of which compound 5: with an N-methyl group and compound 7: with a methoxy at C-16 showed stronger effects on ventricular contraction than the other compounds. Thus, 18-OH is a critical structural feature determining cardiotonic activity, and efficacy is improved by the presence of N-methyl or methoxy at C-16. Preliminary mechanistic studies suggested that the cardiotonic effect of compound 5: is mediated by enhanced cellular calcium influx. Metabolites of TA with these structural features may be useful therapeutics to prevent heart failure.

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.

Pd/Cu catalyzed carbonylation of α-aminoaryl-tethered alkylidenecyclopropanes: synthesis of furoquinoline derivatives

A Pd/Cu catalyzed carbonylation of α-aminoaryl-tethered ACPs for the synthesis of furoquinoline derivatives has been developed. Oxygen was used as the terminal oxidant.