Novel bioactive breviane spiroditerpenoids from Penicillium brevicompactumDierckx

The structures of four new, naturally occurring bioactive spiroditerpenoids , (+)-breviones B, C, D, and E, potential allelopathic agents, have been de termined from extracts of semisolid fermented Penicillium brevicompactum Di erckx. The structures display the novel breviane spiroditerpenoid skeleton. Structure elucidation was-performed by chemical transformations and by hom o- and heteronuclear BD-NMR spectral data. On the basis of combined studies of the theoretical conformations and NOEDIFF data, their relative stereoch emistry is proposed. A mixed biogenesis for this novel family of spiroditer penoids is tendered. The levels:bf activity shown by breviones B, C, and E in the etiolated wheat coleoptiles bioassay, especially breviones E (100% i nhibition) and C (80% inhibition) both at 10(-4) M, suggest them as lead co mpounds for new agrochemicals.