Title
Unusual dimeric tetrahydroxanthone derivatives from Aspergillus lentulus and the determination of their axial chiralities
Author
Tian-Xiao Li, Ming-Hua Yang, Ying Wang, Xiao-Bing Wang, Jun Luo, Jian-Guang Luo, Ling-Yi Kong
Year
2016
Journal
Scientific Reports
Abstract
The research on secondary metabolites of Aspergillus lentulus afforded eight unusual heterodimeric tetrahydroxanthone derivatives, lentulins A−H (2−9), along with the known compound neosartorin (1). Compounds 1−6 exhibited potent antimicrobial activities especially against methicillin-resistant Staphylococci. Their absolute configurations, particularly the axial chiralities, were unambiguously demonstrated by a combination of electronic circular dichroism (ECD), Rh2(OCOCF3)4-induced ECD experiments, modified Mosher methods, and chemical conversions. Interestingly, compounds 1–4 were the first samples of atropisomers within the dimeric tetrahydroxanthone class. Further investigation of the relationships between their axial chiralities and ECD Cotton effects led to the proposal of a specific CD Exciton Chirality rule to determine the axial chiralities in dimeric tetrahydroxanthones and their derivatives.
Full Article
Instrument
J-810
Keywords
Circular dichroism, Absolute configuration, Natural products, Medicinal