Rajinder K. Gupta

Eudesmane derivatives from Verbesina species

Abstract The investigation of seven Verbesina species afforded, in addition to known compounds, several new eudesmane and germacrane derivatives, all bearing a cinnamate or derivatives as residue. Furthermore, a new bisabolene aldehyde and two acetophenone derivatives were isolated. The structures were elucidated mainly by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.

Allenic germacranolides, bourbonene derived lactones and other constituents from Vernonia species

Abstract An investigation of seven Vernonia species, mainly from northern Brazil, afforded in addition to known compounds three new unusual sesquiterpene lactones with an allenic group. Intensive NMR studies fully established the structures. Furthermore, two lactones derived from bourbonene, two new glaucolides, a new furansesquiterpene, a nerolidol derivative and two other sesquiterpenes derived from eudesmane were isolated. The biogenetic relationships of the sesquiterpene lactones present in Veronia species as well as the chemotaxonomic aspects are discussed.

Four guaianolides and other constituents from three kaunia species

Abstract The investigation of three species of the new genus Kaunia afforded four new guaianolides and four thymol derivatives. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.

Diterpenes and tetranorditerpenes from Acritopappus species

Abstract The investigation of four Acritopappus species afforded twenty-three new diterpenes of the labdane or kolavane type and three tetranorditerpenes as well as two new benzofuran derivatives and a hydroxybicyclogermacrene. The structures were elucidated by spectroscopic methods and by some chemical transformations. Though the absolute configuration were not established in all cases, most probably all diterpenes were ent-labdanes or kolavanes (ue5fcclerodanes). The chemotaxonomic importance of this investigation is discussed briefly.

Diterpenes from Mikania species

Abstract The investigation of four further Mikania species afforded several diterpenes, four geranylgeraniol derivatives and three kaurane epoxides. The structures were elucidated by spectroscopic methods and a few chemical transformations.

Three germacranolides and other constituents from Eremanthus species

Abstract The re-investigation of Eremanthus glomerulatus afforded three new germacranolides and a guaianolide, while from E. mollis two known furanoheliangolides and a new phenylpropanol derivative were isolated. The germacranolides most probably are precursors of the widespread glaucolides. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.

Hirsutinolides from Vernonia species

Abstract Out of the nineteen species of Vernonia studied, five contained highly oxygenated sesquiterpene lactones, while the rest contained predominantly triterpenes, especially lupane derivatives.

Notonipetrone-like sesquiterpenes from Senecio Kleinia

Abstract Five new notonipetrone-like sesquiterpenes have been isolated from the roots of Senecio kleinia and their structures elucidated.

Eremophilene and germacrene derivatives from Senecio glanduloso-pilosus

Abstract Senecio glanduloso-pilosus afforded in addition to known compounds a new eremophilene deriva- tive and a hydroperoxide derived from germacrene D.

Guaianolides and furanosesquiterpenes from Ursinia nana

Abstract The investigation of Ursinia nana afforded in addition to the typical known furanosesquiterpenes two new compounds, probably both derived from the