The structure of naturally-occurring cinerin C [systematic name: (7S,8R,3'R,4'S,5'R)-Δ(8')-4'-hydroxy-5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan], isolated from the ethanol extract of leaves of Pleurothyrium cinereum (Lauraceae), has previously been