Plagiochilines T and U, 2,3-secoaromadendranes from the liverwort Plagiochila carringtonii from Scotland
1999
Rycroft, D.S. | Cole, W.J. | Lamont, Y.M.
NMR fingerprinting of five samples of Plagiochila carringtonii has shown that the species in Scotland is characterized by the presence of plagiochilines T and U, two new 2,3-secoaromadendranes, in the ratio 2:1, respectively. Plagiochilines T and U were isolated, characterized by GC-MS and (1)H NMR and the structures elucidated as 2alpha, 15-diacetoxy-2,3-epoxy-2,3-seco- (1alpha,5alpha,6beta,7beta)-aromadendra-3, 10(14)-dien-13-al and methyl 2alpha, 15-diacetoxy-2,3-epoxy-2,3-seco- (1alpha,5alpha,6beta,7beta)- aromadendra-3,10(14)-dien-13-oate, respectively. They differ from plagiochiline C by oxidation of the cyclopropyl beta-methyl substituent to an aldehyde and a methyl ester respectively and are the first recorded examples with oxidation beyond the alcohol level at this position. P. carringtonii may be assigned to the most common Plagiochila chemotype, the 2,3-secoaromadendrane group.
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