New Chlorinated Cyclic Bis(bibenzyls) from the Liverworts Herbertus sakuraii and Mastigophora diclados

Three new cyclic bis(bibenzyls), 2,12-dichloroisoplagiochin D, 12,7′-dichloroisoplagiochin D and 12,10′-dichloroisoplagiochin C have been isolated from the liverwort Herbertus sakuraii belonging to the Herbertaceae, together with isoplagiochin C and isoplagiochin D which have been isolated from the liverwort Plagiochila fruticosa. Their structures have been elucidated by a combination of 2D-NMR, CD spectra, X-ray crystallographic analysis and comparison of the spectral data with those of the known isoplagiochins. 2,12-Dichloroisoplagiochin D and 12-chloroisoplagiochin D have also been isolated from the liverwort Mastigophola diclados, belonging to the Mastigophoroideae. H. sakuraii is chemically closely related to Mastigophora diclados.