Dehydro-leucodin: a guaiane-type sesquiterpene lactone

Acta Crystallogr Sect E Struct Rep Online. 2011 Dec 1;67(Pt 12):o3470. doi: 10.1107/S1600536811048938. Epub 2011 Nov 30.


Dehydro-leucodin [systematic name: (1S,6S,2R)-9,13-dimeth-yl-5-methyl-ene-3-oxatricyclo-[,6)]trideca-9,12-diene-4,11-dione], C(15)H(16)O(3), is a guanolide isolated from Artemisia douglasiana. The fused-ring system contains a seven-membered ring that adopts a chair conformation, a fused planar cyclo-pentenone ring and a five-membered lactone ring fused in envelope conformation. The absolute structure determined by X-ray analysis agrees with that previously assigned to this compound by NMR studies [Bohlmann & Zdero (1972 ▶). Tetra-hedron Lett.13, 621-624] and also with that of leucodine, a closely related guaianolide [Martinez et al. (1988 ▶). J. Nat. Prod.51, 221-228].