Gutierrezial and further diterpenes from Gutierrezia sarothrae

The aerial parts of Gutierrezia sarothrae afforded in addition to polyalthic acid, daniellic acid and nivenolide, 14 new diterpenes, most of them closely related to polyalthic acid. One of these compounds has a new carbon skeleton. The structures were elucidated by spectroscopic methods and by some chemical transformations.