The first 12.8β-germacrolide and other constituents from bolivian Stevia species

The aerial parts of Stevia sarensis afforded several known germacranolides, guaianolides and labdane derivatives while S. samaipatensis gave four new guaianolides, one being a fulvene and two new labdane derivatives. From S. yacomensis four new longipinene derivatives and a guaianolide were isolated. The aerial parts of S. polyphylla afforded in addition to known compounds nine further guaianolides and the first 12.8β-germacrolide. Structures were elucidated by high field NMR spectroscopy and a few chemical transformations.