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A new eudesmanolide, 1-oxo-11 αH-eudesma-2,4(14)-dien-12,8 β-olide ( 1), and four new guaianolides, 9 β,10 β-epoxy-4 α-hydroxy-1 βH,11 αH-guaian-12,8 α-olide ( 2), 9 β,10 β-epoxy-4 α-hydroxy-1 βH,11 βH-guaian-12,8 α-olide ( 3), 4 α,9 α-dihydroxy-1 βH,11 αH-guai-10(14)-en-12,8 α-olide ( 4), and 4 α,9 α-dihydroxy-1 βH,11 βH-guai-10(14)-en-12,8 α-olide ( 5), together with one known eudesmanolide and two known germacranolides, were isolated from the whole plants of Carpesium triste. Their structures and relative configurations were elucidated on the basis of spectroscopic methods, including 2D-NMR techniques. [ABSTRACT FROM AUTHOR]

isolation and structure of new eudesmanolide (I) and guaianolides (II),(III) [ABSTRACT FROM AUTHOR]

The title compound, C(15)H(20)O(4), is a eudesmanolide isolated from the Chinese medicinal plant Carpesium tris-te Maxim. The mol-ecule contains three rings, viz. two fused six-membered rings in chair conformations and a five-membered ring in a flattened envelope conformation. In the crystal, two hy-droxy groups are involved in the formation of intra- and inter-molecular O-H⋯O hydrogen bonds. The H atoms in these groups are split, with site-occupation factors of 0.5. The inter-molecular hydrogen bonds link mol-ecules into chains propagating in [010].

The title eremophilenolide, C(15)H(22)O(3), is a natural compound isolated from Senecio laetus Edgew. The two cis-fused six-membered rings have chair confomations and the five-membered ring has a planar envelope conformation [maximum deviation = 0.010 (1) Å]. The β-hy-droxy group participates in inter-molecular O-H⋯O hydrogen bonding, forming mol-ecular chains along the a axis.

The title compound, C(18)H(26)O(7), is an eremophilenolide which has been isolated from the plant Ligularia duciformis for the first time. The present study confirms the atomic connectivity assigned on the basis of (1)H and (13)C NMR spectroscopy. The mol-ecule contains three fused rings, two six-membered rings in chair confomations and a five-membered ring in a flattened envelope conformation. Two hy-droxy groups are involved in formation of intra- and inter-molecular O-H⋯O hydrogen bonds. The latter ones link mol-ecules into chains propagating in [010].