Orsellides A–E: An Example for 6‐Deoxyhexose Derivatives Produced by Fungi

The antibacterial orsellides A–E ( 1 – 5 ), novel esters consisting of orsellinic acid ( 6 ) and a 6‐deoxyhexose, were isolated from Chaetomium sp . (strain Gö 100/9) together with the known metabolites globosumones A ( 7 ) and B ( 8 ). The structures of the new compounds were elucidated by detailed spectroscopic analysis. The biosynthesis of these metabolites was studied by feeding 13 C‐labelled precursors to growing cultures of strain Gö 100/9. The sugar moieties of the orsellides A–E ( 1 – 5 ) as well as the side chains of globosumones A ( 7 ) and B ( 8 ) originate from carbohydrate intermediates. Thus, the orsellides are rare examples for fungal metabolites containing deoxyhexose building blocks that are normally characteristic for bacterial secondary metabolites. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)