A new germacranolide from Ageratina vernalis .

The aerial parts of Ageratina vernalis provided the new germacranolide 1,10-epoxydeltoidin A ( 3 ), together with the known pentacyclic triterpenoid hopane-6 α ,22-diol ( 1 ), and the also known germacranolides deltoidin A ( 2 ) and 15-hydroxydeltoidin A ( 4 ). In addition, p TsOH catalyzed cyclization of 2 afforded the new guaianolide 5 . The absolute configuration of 2 , 4 , and 5 was assigned by vibrational circular dichroism spectroscopy, while the complete ¹ H and ¹³ C NMR data assignments of 2 - 5 followed from 1 D- and 2 D-NMR experiments.