TMC-264, a Novel Antiallergic Heptaketide Produced by the Fungus Phoma sp. TC 1674

TMC-264 (1), a novel tricyclic heptaketide with a unique chloro-1H-dibenzo[b,d]pyran-4,6-dione skeleton, was discovered from the fungus Phoma sp. TC 1674. The structure was elucidated on the basis of NMR analyses of normal abundance and biosynthetically 13C-enriched TMC-264. TMC-264 showed potent inhibitory activity against tyrosine phosphorylation of STAT6.