Sesquiterpene Lactones From Centaurea-Hermannii

The aerial parts of Centaurea hermannii, an endemic plant of Turkey, yielded three new highly oxygenated guaianolides, 15-deschloro-15-hydroperoxychlorojanerin 15-deschloro-15-hydroperoxychlorohyssopi B and 15-deschloro-3 beta-acetoxy-15-hydroxy-chlorojanerin in addition to four known guaianolides, cynaropicrin, janerin, 19-desoxy-chlorojanerin and 15-deschloro-15-acetoxychlorojanerin, and sitosteryl 3 beta-D-glucoside, beta-sitosterol and alpha-amyrin. The structures were elucidated by high field NMR techniques and chemical transformations.