Talaromynoids A-E: Five New Fusicoccane Diterpenoids from the Endophytic Fungus Talaromyces sp. DC-26

摘要

Talaromynoids A-E(1-5),five new fusicoccanediterpenoids, were obtained from the endophytic fungusTalaromycessp. DC-26, which was isolated from a wild leech.Talaromynoid A (1) represents thefirst fusicoccane diterpenoidbearing an unexpected 5-7-5 tricyclic ring system, which ispossibly derived from normal 5-8-5 ones by ring contraction.Talaromynoid E (5) is characterized by an unusual oxygen bridgebetween C-1 and C-8 that establishes the eight-membered ring Bto be a 9-oxo-bicyclo[3.3.1]nonane. Structures of1-5withabsolute configurations were determined by extensive NMRspectral analyses, electronic circular dichroism (ECD) calculations, X-ray diffraction analyses, and acid hydrolysis.

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