Narendra Kumar

Sesquiterpene lactones from Helianthus grosseserratus

Abstract The isolation is reported of six new sesquiterpene lactones based on the eudesmanolide, trans , trans -germacradienolide and heliangolide skeletons from Helianthus grosseserratus Martens. The diterpenes grandifloric, 17-hydroxy- ent -isokaur-15-enic and ciliaric acids and the flavones hispidulin and pectolinarigenin were also found.

Sesquiterpene lactones of Calea zacatechichi and C. urticifolia

Abstract Calea zacatechichi yielded the sesquiterpene lactone zexbrevin and a new analog, several analogs of neurolenin B including calein A, two analogs of budlein A and the flavones acacetin and O-methylacacetin. Calea urticifolia contained additional analogs of neurolenin B as well as a series of epoxidation products. Structures were established by spectrometric techniques. The results are contrasted with previous findings.

Heliangolides from Helianthus maximiliani

Abstract The isolation is reported of tifruticin, acetyltifruticin, deoxytifruticin, acetyldeoxytifruticin, an orizabin analog and three heliangolides from Helianthus maximiliani .

Minor sesquiterpene lactones of Helianthus pumilus

Abstract The isolation of four known and two new germacradienolides and one known heliangolide from Helianthus pumilus , in addition to the previously report

Sesquiterpene lactones and other constituents of Eupatorium lancifolium and E. semiserratum

Abstract The isolation of the cytotoxic and/or antileukaemic heliangolides eupacunolin, eupacunin, desacetyleupacunin, a new germacradienolide and a coumarin fr

Aromatic and other constituents of four Verbesina species: Structure and stereochemistry of verbesindiol

Abstract Chemical examination of Verbesina sublobata, V gigantea , V. myriocephala and V virginica yielded mainly aromatic aldehydes and acids along with 2,6-dimethoxybenzoquinone and euparin as colouring matters. V virginica also gave the p -coumarate ester of a new sesquiterpenediol, verbesindiol, related to the verbesinols whose structure and stereochemistry were elucidated.

Damsinic acid and ambrosanolides from vegetative ambrosia hispida

Abstract Ambrosia hispida in the vegetative state furnished large quantities of damsinic acid and smaller amounts of ambrosin and damsin. Also isolated were anhydrocoronopilin, hispidulin and the new compounds 3-hydroxyambrosin damsinate and ent -12-oxokaura-9(11),16-dien-19-oic acid.

Sesquiterpene lactones of Baltimora recta

The major sesquiterpene lactone of B. recta was the alantolide encelin (1) previously isolated from Encelia furinosa (Helianthinae) [4]. ‘H and 13C NMR spectra of encelin are included in Tables 1 and 2; in accordance with our earlier revision [S] of the structure of farinosin (5), the original assignments for H-13 and H-14 of encelin [4] must be interchanged. The previously unreported CD curve of 1 (see Experimental) exhibited multiple Cotton effects due to the presence of a

Guaianolides from Liatris squarrosa

-

Sesquiterpene lactones of Eupatorium serotinum

Abstract The isolation of three new guaianolides related to spicatin from Liatris squarrosa is reported.