Aspochalamins A-D and aspochalasin Z produced by the endosymbiotic Fungus Aspergillus niveus LU 9575. II. Structure elucidation.

The structures of new cytochalasan fungal metabolites aspochalamins A-D have been elucidated by ESI-FTICR-MS, NMR spectroscopy, and chiral amino acid analysis. Aspochalamins A-D consist of different aspochalasin skeletons connected at position C-19 to the N terminus of the tripeptidic moiety amide anthranoyl-L-alanine-E-didehydrotryptamide. Furthermore, the structure of a new aspochalasin analog, aspochalasin Z, was derived from its molecular mass and NMR data as 10-isopropyl-14-methyl[11]-cytochalasa-6Z,13E,19E-triene-1,21-dione.