Pahup Singh

Three cadinene derivatives and a prostaglandin-like acid from Chromolaena species

Abstract An investigation of the aerial parts of Chromolaena chasleae afforded a prostaglandin-like acid, whose structure followed from the 1H NMR spectral data and from the reaction with periodate, which afforded a hemiacetal. From a new Chromolaena species, three novel cadinene derivatives were isolated, which were closely related to those isolated previously from this genus.

Eremophilane derivatives and other constituents from Senecio species

Abstract The investigation and reinvestigation respectively of 23 Senecio species afforded 11 further cacalol derivatives, a furoeremophilone, 17 eremophilanes, 4 bisabolene derivatives, a shikimic acid derivative, a bis -prenylated p -hydroxybenzaldehyde, menth-2-en- 1,7-diol and a cumol derivative. The configuration of some eremophilanes have been revised. Structures were elucidated by spectroscopic methods. The results are summarized in a table. The chemotaxonomic aspects agree with those of previous investigations.

Further ineupatorolide-like germacranolides from Inula cuspidata

Abstract The aerial parts of Inula cuspidata afforded in addition to known compounds five germacranolides closely related to ineupatorolide A. Furthermore,

Xanthanolides from Xanthium indicum

Abstract From the aerial parts of Xanthium indicum, in addition to known compounds, two new xanthanolides were isolated and the stereochemistry of xanthumin

Germacranolides from Dicoma tomentosa

Abstract An investigation of the aerial parts of Dicoma tomentosa afforded four new germacranolides and four melampolides together with urospermal A and its 11β,13-dihydroderivative. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.

New germacranolides and other sesquiterpene lactones from Dicoma species

Abstract Two subspecies of Dicoma anomala afforded, in addition to known compounds, an eudesmanolide, a guaianolide and four germacranolides, the latter being closely related 8, 12-lactones. D. schinzii gave three new germacranolides and D. zeyheri a pair of isomeric acetylenic compounds. The structures were elucidated by highfield 1 H NMR spectroscopy. The chemotaxonomic situation of this genus is discussed briefly.

Three bourbonenolides and other sesquiterpene lactones from two vernonia species

Abstract A re-investigation of V. arkansana afforded several new sesquiterpene lactones, three bourbonenolides, obviously closely related to those isolated from this plant previously, a glaucolide and a methoxy derivative most probably formed by fragmentation of the corresponding bourbonenolide. From V. profuga in addition to known lactones a new guaianolide was isolated. The biogenetic relationships of the Vernonia sesquiterpene lactones are discussed briefly.

Furanoheliangolides from two Eremanthus species and from Chresta sphaerocephala

Abstract The investigation of Eremanthus crotonoides afforded in addition to known compounds three new furanoheliangolides, while from E. glomerulatus six new furanoheliangolides and eremantholides were isolated. From the aerial parts of Chresta sphaerocephala a new guaianolide was obtained, while the roots contained known furanoheliangolides. The chemotaxonomy of the subtribe Lychnophorinae is discussed briefly.

An epoxygermacranolide and further constituents from Mikania species

Abstract Mikania purpurascens afforded in addition to known compounds a 5,10-epoxygermacranolide, while M. arrojadoi gave only known ent -kaurene derivatives.

Isocedrene derivatives and other sesquiterpenes from moscharia pinnatifida

Abstract From the aerial parts of Moscharia pinnatifida nine further α-isocedrene, two guaiane, three cyperene and two nerolidol derivatives were isolated. The structures were elucidated by high field NMR studies. Chemotaxonomic aspects are discussed.