Dioxatricyclic and oxabicyclic polyketides from Trichocladium opacum
Shenxi Chen1, Fengxia Ren, Shubin Niu
1State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.
Abstract:
Five new polyketides, trichocladinols D-H (1-5) with dioxatricyclic (1-3) and oxabicyclic (4 and 5) skeletons, and the known massarilactone C (6) were isolated from the solid-substrate fermentation cultures of the ascomycete fungus Trichocladium opacum. The structures of 1-5 were determined mainly by NMR experiments, and 1, 3, and 4 were confirmed by X-ray crystallography. The absolute configurations of 1 and 3 were assigned by X-ray crystallography using Cu Kα radiation, whereas that of C-5 in 2 and 4 was deduced via the circular dichroism (CD) data. Compounds 2-4 showed weak cytotoxicity against the human tumor cell lines A549, HCT116, and SW480.
More Related Videos
Related Concept Videos
Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
Thermal and Photochemical Electrocyclic Reactions: Overview
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Antifungal Agents
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Aryldiazonium Salts to Azo Dyes: Diazo Coupling

![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
