Prenylated bibenzyl derivatives from Lethocolea glossophylla and Radula voluta

Phytochemical investigation of the liverwort, Lethocolea glossophylla, yielded five new prenylated bibenzyl derivatives. Their structures were elucidated by spectral analysis as 2-carboxy-3-methoxy-4,6-di-(3-methyl-2-butenyl)-5,4'-dihydroxy-bibenzyl, 2,4-di-(3-methyl-2-butenyl)-3,5,4'-trihydroxy-bibenzyl, 2,2-dimethyl-5-hydroxy-6-(3-methyl-2-butenyl)-7-[2-(4'-hydroxyphenyl)-ethyl]-chromene, 2,2-dimethyl-5-hydroxy-7-[2-(4'-hydroxyphenyl)-ethyl]-8-(3-methyl-2-butenyl)-chromene and as a bisprenylated bisbibenzyl (glossophyllin) with a chromene and a chromane moiety. From Radula voluta, the previously known bibenzyls, 2-(3-methyl-2-butenyl)-3,5-dihydroxy-bibenzyl and 2-geranyl-3,5-dihydroxy-bibenzyl, were isolated and identified. (C) 1997 Elsevier Science Ltd.