Studies on fungal products. Part 10. Isolation and structures of novel bicoumarins, desertorins A, B, and C, from Emericella desertorum

Abstract

Together with silvaticol (11), nidulol (12), ergosterol, paxilline (10), and mannitol, three new bicoumarins designated as desertorin A (1)(C₂₂H₁₈O₈), B (2)(C₂₃H₂₀O₈), and C (3)(C₂₆H₂₂O₈) have been isolated from Emericella desertorum, strain CBS 653.73. The structures of desertorins A (1), B (2), and C (3) were determined on the basis of the spectroscopic and chemical investigations of these compounds and their derivatives i.e., as 7,7′-dihydroxy-4,4′-dimethoxy-5,5′-dimethyl-6,8′-bicoumarin, 5,5′-dimethyl-6,8′-bicoumarin, 5,5′-dimethyl-7-hydroxy-4,4′,7′-trimethoxy-6,8′-bicoumarin and 5,5′-dimethyl-4,4′,7,7′-tetramethoxy-6,8′-bicoumarin, respectively. It is interesting to note that silvaticol (11) and nidulol (12), both of the known metabolites of Aspergillus silvaticus, were isolated from the same extracts.