Glyclauxins A-E: Dimeric Oxaphenalenone Aminoglycosides from an Australian Wasp Nest-Derived Fungus Talaromyces sp. CMB-MW102.

ABSTRACT

Chemical analysis of cultures of a Queensland mud dauber wasp nest-derived fungus, Talaromyces sp. CMB-MW102, yielded the known dimeric oxaphenalenone duclauxin (1) along with a family of new 1-deoxy-d-glucosamine adducts, glyclauxins A-E (2-6). Despite 1D NMR spectra of 2-6 being compromised by broadening of selected resonances, structures inclusive of absolute configuration were assigned on the basis of detailed spectroscopic analysis and biogenetic considerations, as well as biomimetic semisynthesis and chemical interconversion. For example, exposure of duclauxin (1) to synthetic 1-deoxy-d-glucosamine yielded glyclauxin B (3), while on handling and storage, glyclauxins C (4) and D (5) (bearing a 7-OMe moiety) proved chemically labile and underwent quantitative transformation to glyclauxins B (3) and A (2), respectively. These latter observations on chemical reactivity and stability informed a proposed biogenetic relationship linking all known members of the extended duclauxin family. Notwithstanding their potential status as artifacts, the detection of glyclauxins B (3) and A (2) in a fresh CMB-MW102 culture extract confirmed their natural product status.