Grosulfeimin and New Related Guaianolides from Cynara Scolymus L

Abstract Three new guaianolides, 11-H-13-methylsulfonylgrosheimin (5) (grosulfeimin), 8-deoxy-11, 13-dihydroxygrosheimin (7) and 8-deoxy-11-hydroxy-13-chlorogrosheimin (8) have been isolated from the leaves of Cynara scolymus L. Furthermore, the already known 8-epigrosheimin (9) has been isolated for the first time from this source. The structures were determined by both spectroscopical methods and chemical correlations.