Iryantherins, lignoflavonoids of novel structural types from the myristicaceae

Iryanthera laevis, I. ulei and I. paraensis contain a series of novel lignoflavonoids the formation of which can be rationalized by the cinnamylation of the phloroglucinol type A-ring of a dihydrochalcone. The lignoid attachments of the flavonoid moieties consist of an arylvinylmethyl group in iryantherin-A, of 1,4-diaryl-2,3-dimethyl-n-butyl groups in iryantherins B and C and of 3-aryl-2-cinnamyl-n-propyl groups in iryantherins D and E. The construction of iryantherin-F requires oxidative addition of the vinyl unit of an iryantherin-A type compound to the A-ring of a second dihydrochalcone moiety.