ent-Labdane Diterpenoids from the Aerial Parts of Eupatorium obtusissmum.

Six new ent-labdane diterpenoids, uasdlabdanes A-F (1-6), were isolated from the aerial parts of Eupatorium obtusissmum. The new structures were elucidated through spectroscopic and spectrometric data analyses. The absolute configurations of compounds 1 and 2 were established by X-ray crystallography, and those of 3-6, by comparison of experimental and calculated electronic circular dichroism spectra.

A chemotaxonomic study of endemic species of genus Tanacetum from the Canary Islands.

Aerial parts of Tanacetum oshanahanii collected at "Jardín Canario Viera y Clavijo", Tanacetum ptarmiciflorum collected at Los Moriscos (Tejeda), and Tanacetum ferulaceum var. latipinnum collected at Anden Verde (Agaete) in Gran Canaria, Canary Islands, afforded three sesquiterpenes related to nerolidol and six sesquiterpene lactones whose structures were established on the basis of their spectroscopic data and chemical transformations. In this work we show that this type of sesquiterpene lactones could be used as chemotaxonomic markers.