Lichen substances. X. Physciosporin, a new chlorinated depsidone

Physciosporin, a new chlorinated depsidone, has been isolated from the lichen Pseudocyphellaria physciospora and identified as methyl 2-chloro-4-formyl-3,8-dihydroxy-1,6,9-trimethyl-11-oxo-11H-dibenzo[b,e][1,4]dioxepin-7-carboxylate (methyl 5-chlorovirensate), 1.