The absolute configurations at five chiral centers in amphidinolide Q (1), a cytotoxic 12-membered macrolide isolated from a marine dinoflagellate Amphidinium sp., were elucidated to be 4R, 7R, 9S, 11R, and 13R on the basis of NMR analyses and a modified Mosher's method.
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Toxins (Basel)
December 2024
Department of Chemistry, University of Ghana, Legon-Accra P.O. Box LG56, Ghana.
Mycolactone is a complex macrolide toxin produced by , the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities.
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
February 2025
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.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
Two new acylphloroglucinol-nerolidol meroterpenoids (APNMs) [(±)-1 and (±)-2], with a skeleton of mixed sesquiterpene and dimeric acylphloroglucinol biosynthetic origin, were isolated from the medicinal pteridophyte . Inspired by the proposed biosynthetic pathway, we initially completed the biomimetic syntheses of eight optically active APNMs (1-8) in a one-pot domino reaction. The structures of APNMs 1-8 including their absolute configurations were unambiguously established by a combination of NMR analysis, ECD calculations, and synthetic methods.
View Article and Find Full Text PDFWe report the first asymmetric total synthesis of recently isolated heterodimeric alkaloids, narcipavlines A (1a) and B (1b), and narcikachnines A (2a) and B (2b), thereby confirming their absolute stereochemistry. These alkaloids showcase a unique heterodimeric structure, amalgamating two distinct types of alkaloids: the -hydrodibenzofuran containing tetracyclic galantamine core (6a) and the galanthindole core (7) featuring a biaryl axis. The presence of this biaryl axis, coupled with the substantial galantamine core (6a) at the substituents, imposes constraints on free rotation around the C-C axis, resulting in atropisomerism, an exceedingly rare phenomenon in nature.
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