Viridin. Part 8. Structures of the analogues virone and wortmannolone

The secondary metabolic products virone (from Gliocladium virens) and wortmannolone (from Penicillium wortmannii) are shown to be pregna-5,8-dieno[6,5,4-bc]furan-3,7,20-trione and 1α,2α-epoxy-3β-hydroxyandrosta-5,8-dieno[6,5,4-bc]furan-7,17-dione, respectively.