A concise synthesis of 8-azabicyclo[3.2.1]octanes via sequential oxidative Mannich reactions is described. This approach involves an intermolecular oxidative Mannich coupling reaction between N-aryl pyrrolidines with TMS enol ether and a subsequent intramolecular oxidative Mannich cyclization of the corresponding silyl enol ether. DDQ is used as a key oxidant for both reactions.
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http://dx.doi.org/10.1021/acs.orglett.8b00098 | DOI Listing |
Acc Chem Res
January 2025
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China.
ConspectusThe Mannich reaction, involving the nucleophilic addition of an enol(ate) intermediate to an imine or iminium ion, is one of the most widely used synthetic methods for the synthesis of β-amino carbonyl compounds. Nevertheless, the homo-Mannich reaction, which utilizes a homoenolate intermediate as the nucleophilic partner and provides straightforward access to the valuable γ-amino carbonyl compounds, remains underexplored. This can be largely attributed to the difficulties in generation and manipulation of the homoenolate species, despite various homoenolate equivalents that have been developed.
View Article and Find Full Text PDFNat Commun
December 2024
Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
The functionalized polycycle with densely contiguous tertiary stereocenters is a formidable challenge in synthesizing the parvistemoline family of Stemona alkaloids. We herein report their catalytic, asymmetric total syntheses in 13-14 steps from commercially available 2-(methoxycarbonyl)-pyrrole, featuring the development and deployment of an Ir/Pd-synergistically-catalyzed allylation of α-non-substituted keto esters with secondary aryl-substituted alcohols, stereodivergently accessible to four stereoisomers. Using chiral Pd-enolate and Ir π-allyl complex under neutral conditions, no epimerization occurs.
View Article and Find Full Text PDFJ Nanobiotechnology
December 2024
School of Life and Environmental Sciences, Shaoxing University, Shaoxing, 312000, Zhejiang, China.
Anthracycline doxorubicin (DOX) remains the first-line chemotherapeutic drug for the efficient treatment of breast cancer, but its severe cardiotoxicity limits its long-term application in clinical tumor chemotherapy. Until now, the pathogenesis mechanism of DOX-induced cardiotoxicity (DIC) is still not fully understood. According to current studies, the oxidative stress caused by the imbalance of reactive oxygen species (ROS) and reactive nitrogen species (RNS) production and mitochondrial dysfunction in myocardial cells are closely related to DIC.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Food and Light Industry, Nanjing Tech University, Nanjing 211816, China.
In this study, four different arginine-modified lignin composites (Lig-Arg-x) were synthesized via the Mannich reaction, followed by the preparation of Lig-Arg-x/FeO magnetic nanoparticles (NPs) using hydrothermal reduction. The magnetic particles were characterized, and their emulsification properties were investigated. The highest grafting degree was achieved at a 1:1 M ratio of arginine to lignin.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Materials Science and Engineering, University of Jinan, Jinan 250022, PR China; School of Pharmaceutical Sciences & Institute of Materia Medica, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, PR China. Electronic address:
Green and high-performance biomass-based adsorbents have a good application prospect for the removal of heavy metals. At present, the preparation of chitosan/lignin biomass adsorbents mainly adopts dissolution-drying method, and the obtained adsorbents show relatively poor adsorption performance for heavy metals. To overcome this problem, a novel chitosan/lignin hydrogel (CSL) is prepared by a simple one-pot method through the Mannich reaction.
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