Phomalevones A-C: Dimeric and pseudodimeric polyketides from a fungicolous Hawaiian isolate of Phoma sp. (Cucurbitariaceae).

Phomalevones A-C (1-3), three new compds. with bis-dihydroxanthone and bis-benzophenone systems, were isolated from cultures of a Hawaiian isolate of Phoma sp. (MYC-1734 = NRRL 39060; Cucurbitariaceae). The structures of 1-3 were detd. by anal. of NMR and MS data. The abs. configurations of the sp3 stereocenters in the monomeric unit of 1 were assigned by application of Mosher's method, and overall abs. configurations were proposed on the basis of ECD data using both computational methods and comparisons with literature data for model compds. All three compds. showed antibacterial activity, and compds. 2 and 3 also exhibited antifungal effects. [on SciFinder(R)]