Secondary mould metabolites. Part 47. Isolation and structure elucidation of clavilactones A–C, new metabolites from the fungus Clitocybe clavipes

Abstract

Clavilactones A–C (1, 4 and 5) have been isolated from cultures of the Basidiomycetous fungus Clitocybe clavipes. Their structures and relative configurations have been deduced from ¹H and ¹³C NMR studies, chemical reactions and single-crystal X-ray analysis of the dimethyl ether derivative 3. ¹H–¹H coupling constants, NOE data and molecular modelling calculations all suggest that the molecules have little conformational mobility and the conformation adopted in solution by clavilactone A 1 and dimethyl ether derivative 3 is essentially identical with that of 3 in the solid state. Clavilactones A–C exhibit antifungal and antibacterial activity and inhibit the growth germination of Lepidium sativum. A possible biogenetic origin of clavilactone A 1 is discussed.