Stereochemical studies of the photocycloaddition of a chiral alpha,beta-enone and isobutylene lead to a working hypothesis for the geometry of the 3(pi-pi*) excited state of the enone. [reaction: see text]
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ACS Chem Neurosci
December 2024
Department of Chemistry, Center for Research and Advanced Studies (Cinvestav), Mexico City 07360, Mexico.
Alzheimer's disease (AD) is the most common form of dementia worldwide. AD brains are characterized by the accumulation of amyloid-β peptides (Aβ) that bind Cu and have been associated with several neurotoxic mechanisms. Although the use of copper chelators to prevent the formation of Cu-Aβ complexes has been proposed as a therapeutic strategy, recent studies show that copper is an important neuromodulator that is essential for a neuroprotective mechanism mediated by Cu binding to the cellular prion protein (PrP).
View Article and Find Full Text PDFRSC Adv
December 2024
Departamento de Química Orgánica, Laboratorio de Química Farmacéutica, Facultad de Quimica, Universidad de la República Gral Flores 2124 Montevideo 11800 Uruguay
A new series of chiral δ-thiolactone derivatives have been prepared. These compounds exemplify the acetalic N-C-S reversibility of fused thiazolidines toward the thermodynamic product. The stereochemistry of the synthesized compounds was elucidated using X-ray crystallography, NOESY spectroscopy, and DFT calculations.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
(-)-Exiguolide is a marine macrolide natural product with potent anticancer activity. In this study, the total synthesis of exiguolide stereoisomers, (9)-exiguolide, (9,13)-exiguolide, and (9,13,19)-exiguolide, was achieved by capitalizing on our macrocyclization/transannular pyran cyclization strategy. The impact of the stereochemical permutation on the reactivity of advanced intermediates, the conformation of the macrocyclic skeleton, and the antiproliferative activity against human cancer cells were investigated in detail.
View Article and Find Full Text PDFNat Prod Rep
December 2024
Chinese Pharmacopoeia Commission, Beijing 100061, China.
Covering: 2009 up to the end of 2023Stilbenes, an emblematic group of polyphenols, have attracted the attention of numerous researchers owing to their intriguing polycyclic architectures and diverse bioactivities. In this updated review, natural stilbenes were analysed, especially oligomeric stilbenes, which are an emblematic group of polyphenols that harbor intriguing polycyclic architectures and diverse bioactivities compared with those previously anticipated. Oligomeric stilbenes with unique skeletons comprise a large majority of natural stilbenes owing to their structural changes and different substitutions on the phenyl rings.
View Article and Find Full Text PDFEur J Med Chem
December 2024
Shaanxi Key Laboratory of Natural Products & Chemical Biology, Shaanxi Engineering Center of Bioresource Chemistry & Sustainable Utilization, College of Chemistry & Pharmacy, Northwest A&F University, Yangling, 712100, PR China. Electronic address:
Eleven new chromane meroterpenoids (1-11), along with 24 known ones (12-35) were isolated from Rhododendron capitatum, a Tibetan medicine. Their structures were determined via extensive spectroscopic methods. The absolute configurations of 1 and 2 were determined by comparison of the experimental and theoretically calculated ECD data.
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