Eudesmane Derivatives from Hieracium intybaceum

Two new eudesmanolides, 4β-H,3β-(β-D-glucopyranosyloxy)eudesma-1,11(13)-dien-12,6-olide (5a) and 3β-D-glucopyranosyloxyeudesma-1,4(15),11(13)-trien-12,6-olide (5b), as well as two related, known compounds, tuberiferin (7a) and dehydrobrachylaenolide (7b), were isolated from the CH₂Cl₂ extract of subaerial parts of Hieracium intybaceum All. Compounds 6a, 6b, 8a, and 8b, the Me esters of the corresponding sesquiterpenic acids related to 5a, 5b, 7a, and 7b, respectively, were obtained as artifacts during the isolation process. Additionally, linoleic acid (1), linolenic acid (2), the lignane syringaresinol 4′-O-β-D-glucopyranoside (3), and the guaianolide dehydrocostus lactone (4) were also isolated from H. intybaceum. Structure elucidations were based on mass spectrometry and extensive 1D- and 2D-NMR spectroscopy.