LIGNANS FROM ARISTOLOCHIA-BIROSTRIS

The investigation of a specimen of Aristolochia birostris afforded, in addition to β-sitosterol, seven lignoids: rel-(8R)-Δ8′-3,4-methylenedioxy-5,3′,5′-trimethoxy-, rel-(8R)-Δ8′-3,4-methylenedioxy-3′,5′-dimethoxy-, rel-(8R)-Δ8′-3,3′,4,5,5′-pentamethoxy- and rel-(7R,8R)-Δ8′-3,4-methylenedioxy-3,5,5′-trimethoxy-7-hydroxy-8.0.4′-neolignan; rel-(8R,8′R)-3,4; 3′,4′-dimethylenedioxy-9-oxo-, rel-(8R,8′R)-3,4; 3′,4′-dimethylenedioxy-9β-hydroxy- and rel-(8R,8′R)-3,4; 3′,4′-dimethylenedioxy-9α-hydroxy-8.8′,9.0.9′-lignan and rel-(7S,8S,7′R,8′R)-3,3′,4,4′,5,5′-hexamethoxy-7.0.7′,8.8′-lignan. The structures were elucidated by spectroscopic analysis. © 1990.