Isodehydrocostus lactone and isozaluzanin C,two guaianolides from Saussurea lappa

Two new guaianolides have been isolated from Saussurea lappa as minor components and have been named isodehydrocostus lactone and isozaluzanin C. A structure has been assigned to isodehydrocostus lactone on the basis of spectral data and correlation with estafiatin. The ¹H NMR data and dehydrogenation studies show that the other highly crystalline guaianolide is isomeric with zaluzanin C. Earlier 3β-H-zaluzanin C has however been reported to occur as a colourless oil.     

Sesquiterpene lactones of Ambrosia cordifolia

Extraction of Ambrosia cordifolia (Gray) Payne furnished the modified pseudoguaianolides psilostachyin C (I) and cordilin. The latter was shown to be a stereoisomer IV of psilostachyin (II). Dicorea brandegei Gray and D. canescens T. &. G. yielded no crystalline lactone components.     

The structure and stereochemistry of phlogantholide-A,a diterpene from Phlogacanthus thyrsiflorus

The structure and stereochemistry of phlogantholide-A, a new diterpene lactone isolated from the leaves of Phlogacanthus thyrsiflorus has been determined as 2β,15,18-trihydroxy-ent-labd-8(17),13-dien-16-oic lactone by chemical and spectroscopic means.     

A new sapogenin in the saponins of Zizyphus jujuba,Hovenia dulcis and Bacopa monniera

Acid hydrolysis of the saponin of the seeds of Zizyphus jujuba afforded ebelin lactone, which yielded the sapogenin, jujubogenin, on Smith-de Mayo degradation. The mechanism of conversion of jujubogenin into ebelin lactone has been elucidated. Hovenoside G of Hovenia dulcis and bacoside A of Bacopa monniera which produce ebelin lactone on acid hydrolysis have also been found to yield jujubogenin on Smith-de Mayo degradation.     

Structure and absolute stereochemistry of vanillosmin,a guaianolide from Vanillosmopsis erythropappa

The structure and absolute stereochemistry of vanillosmin were established by chemical and spectral evidence and by comparison with O-acetyl-isophoto-α-santonic lactone and tetrahydroartabsin “C”.     

(−)-(S,S)-12-hydroxy-13-octadec-cis-9-enolide,a 14-membered lactone from Crepis conyzaefolia seed oil

Crepis conyzaefolia (Gouan) Dalle Torre seed oil contains about 3% of (?)-(S,S)-12-hydroxy-13-octadec-cis-9-enolide (1), a lactone of (?)-threo-12,13-dihydroxyoleic acid. The absolute configuration of the acid has been established as D-12, L-13 (12-S, 13-S) and the lactone has the same absolute configuration.     

Stryspinolactone,an unusual monoterpene lactone from Strychnos spinosa

The structure of stryspinolactone, an unusual lactone from Strychnos spinosa, was determined from spectroscopic data.     

Pigments from Nectria haematococca: Anhydrofusarubin lactone and nectriafurone

The structures of anhydrofusarubin lactone and of nectriafurone, two new naphthoquinone pigments isolated from the fungus Nectria haematococca, are     

Desangeloylshairidin,a sesquiterpene lactone from Guillonea scabra

From the roots of Guillonea scabra a new sesquiterpene lactone has been isolated. Its structure has been established by spectroscopic means as desangeloylshairidin.     

15-oxo-zoapatlin,a diterpene lactone from Viguiera maculata

The isolation of a new diterpene lactone and two known diterpenoid acids from the aerial parts of Viguiera maculata is reported.     

New withanolides of biogenetic interest from Withania somnifera

The structure of 1α,3β,20α_F-trihydroxy-20R,22R-witha-5,24-dienolide, a new naturally occurring steroidal lactone of the withanolide g     

A further sesquiterpene lactone esterified with a sesquiterpenic acid

The roots of Hypochoeris oligocephala afforded in addition to known compounds a further sesquiterpene lactone esterified with a sesquiterpenic acid as well as the corresponding free acid.     

Biotransformation of a guaiane 6,12-diol to the corresponding guaianolide in hypocotyl cuttings of Phaseolus aureus

The hypocotyl cuttings of Phaseolus aureus brought about the biotransformation of a guaiane 6,12-diol to the corresponding lactone during the formation of adventitious roots.     

Naphthoquinone-lactones and extended quinones from Ventilago calyculata

New quinones have been isolated from the root bark of Ventilago calyculata. Ventilatones A and B are benzisochromanquinones, related to the ventiloquinones, which have an additional fused lactone ring while ventileins A and B are benzisochroman dimers having a dihydroxy-peri-xanthenoxanthenequinone chromophore.     

Eudesmanolides from Dimerostemma brasilianum

The investigation of Dimerostemma brasilianum afforded, in addition to known compounds, 18 new eudesmanolides and a new diterpene lactone derived f     

Sesquiterpene lactone glycosides from Crepis capillaris

Four new sesquiterpene lactone glucosides, in addition to known compounds, have been isolated from the roots of Crepis capillaris and their structures elucidated on the basis of spectral analysis and hydrolytic studies.     

Mariolin,a germacranolide from Anacyclus radiatus

A new sesquiterpene lactone, the germacranolide mariolin, was isolated from the aerial part of Anacyclus radiatus along with several known compounds. The structure of mariolin was determined by spectroscopic methods.     

Xanthanolides from Xanthium spinosum

The aerial parts of Xanthium spinosum afforded in addition to known xanthanolides three new ones. The structures were elucidated by spectroscopic methods and by partial synthesis. Furthermore one lactone was transformed to a known derivative.     

Sesquiterpene lactones from Chrysanthemum coronarium

The flower heads of Chrysanthemum coronarium afforded a new sesquiterpene lactone, dihydrocumambrin A, in addition to the known cumambrin A.     

Angeloylcumambrin-B,an antimicrobial sesquiterpene lactone from Chrysanthemum ornatum var. Spontaneum

Angeloylcumambrin-B, a new antimicrobial guaianolide sesquiterpene lactone, was isolated from Chrysanthemum ornatum and the structure was determined by a combination of chemical and physical methods.