SESQUITERPENE LACTONES AND OTHER CONSTITUENTS FROM SCHISTOSTEPHIUM SPECIES

Article abstract of DOI:10.1016/0031-9422(83)80100-9

From four Schistostephium species, in addition to known compounds, 43 new ones were isolated, three isocomene, two bisabolene, two eudesmane, two allo-himachalene and two nerolidol derivatives, two sesquiterpenes with a new carbon skeleton derived from isocomene, nine eudesmanolides, 20 6,12- and 8,12-germacranolides respectively, and a prostaglandin-like acid.The structures were elucidated by spectroscopic methods, especially high field 1H NMR and some chemical transformations.The stereochemistry of some 8,12-germacranolides was established by partial synthesis which required revision of the previous assignments of the configuration of inunolide, its 4,5- and 1,10-epoxide, vernudifloride, simsiolide, 6-hydroxy-1,10-epoxyinunolide and perhaps also of tanachin.The chemotaxonomic situation is discussed briefly.Key Word Index - Schistostephium artemisiifolium; S. crategifolium; S. heptalobum; S. rotundifolium; Compositae; Anthemidae; sesquiterpenes; sesquiterpene lactones; eudesmanolides; germacranolides; prostaglandin-like acid.