Sesquiterpene polyol esters from Celastrus rosthornianus

Two new sesquiterpene polyol esters with β-dihydroagarofuran skeleton were isolated from the root bark of Celastrus rosthornianus. Their structures were elucidated, mainly on the basis of spectral analyses, as 1 β-acetoxy-8β,9-dibenzoyloxy-6-hydroxy-2β(-methylbutanoyloxy)-β-dihydroagarofuran and 1β-acetoxy-9-benzoyloxy-8β-(β-furanocarbonyloxy)-6-hydroxy-2β(-methylbutanoyloxy)-β-dihydroagarofuran. The complete assignments of ¹³C NMR chemical shifts for both compounds on the basis of ¹H-¹³C chemical-shift correlation spectrum were also carried out.     

Pseudoguaianolides carabrone derivatives from Loxothysanus sinuatus

The aerial parts of Loxothysanus sinuatus afforded in addition to known compounds nine new pseudoguaianolides, three guaianolides and five carabrone derivatives. The structures were elucidated by spectroscopic methods. The chemotaxonomy is discussed briefly. The configurations of two guaianolides were corrected.     

Isoalantolactone derivatives and germacranolides from Blumea densiflora

The germacranolides tagitinin A and tirotundin ethyl ether and a series of new ring A-hydroxylated isoalantolactone derivatives were isolated from Blumea densiflora. Structures were established by spectroscopic methods and chemical transformations.     

Irritant phorbol derivatives from four Jatropha species

Four Jatropha species used in folk medicine were screened for irritant constituents. By chromatographic and countercurrent distribution procedures, highly irritant factors were isolated from each species. They represent new polyunsaturated esters of the tigliane-type diterpenoids 16-hydroxyphorbol (J. podagrica, J. multifida) and 12-deoxy-16-hydroxyphorbol (J. curcas, J. gossypifolia).     

Guaianolides,heliangolides, diterpenes and cycloartenol derivatives from Balsamorhiza sagittata

Investigation of the aerial parts of Balsamorhiza sagittata afforded 12 new sesquiterpene lactones, five guaianolides, three heliangolides, three germacranolides and two geranylnerol derivatives. From the roots eight cycloartane derivatives, a hydroxylanosterone and hexacos-1-ene were isolated. Structures were elucidated mainly by spectroscopic methods, especially high field NMR. The chemotaxonomic situation is discussed briefly.     

Homogeranyl nerol derivatives and a melampolide from Smallanthus glabratus

The investigation of the aerial parts of Smallanthus glabratus from two locations afforded the same known compounds but some additional new compounds which were not present in both collections. From the first location typical melampolides, one of them not isolated previously, and two homoditerpenes were isolated. The material from the second location gave four closely related homoditerpenes and two geranyl nerol derivatives from which the homoditerpenes were derived. The structures were elucidated by high field ¹H NMR spectroscopy. Chemotaxonomic aspects are discussed briefly.     

新的β—二氢沉香叶喃倍半萜多酯的HRFABMS和EIMS研究

利用高分辨快原子轰击质谱（HRFABMS）分析了八个新的β－二氢沉香叶喃倍半萜多酯的FABMS。结果表明,所有该类化合物均可以精确地获得[M＋Na]^ 准分子离子的分子组成,从而方便地获得原有化合物分子量和分子式,所测化合物的FABMS谱中均存在[M H-H2O]^ 特征离子,为化合物分子式的确定提供了进一步的佐证;在该类化合物的EIMS谱中,观测不到分子离子的存在,但一般可以获得[MCH3]^ ,[M-Ac]^ ,[M-HOAc]^ 等特征离子以及高强度的酰基离子。将EIMS和FABMS结合起来可以快速准确地获得化合物的分子量、分子式以及相关的取代酰基等结构信息。     

Germacranolides from Eupatoriastrum nelsonii

The aerial parts of Eupatoriastrum nelsonii afforded, in addition to known sesquiterpene lactones, four new lactones all closely related to the germacranolides isolated previously from other genera of the tribe Eupatorieae. The structures were elucidated by spectroscopic methods. Chemotaxonomic aspects are discussed briefly.     

Eudesmanolides from Pluchea dioscoridis

Reinvestigation of the aerial parts of Pluchea dioscoridis afforded, in addition to known compounds, five new eudesmanolides and a new thiophene derivative. The stereochemistry of one of the eudesmanolides isolated previously has been corrected. The structures were elucidated by spectroscopic methods.     

Sesquiterpene lactones from Centaurea glomerata

The investigation of the aerial parts of Centaurea glomerata afforded four new sesquiterpene lactones of the germacradienolide type and the lignan lactone arctigenin. Their structures were elucidated by spectroscopic methods.     

Seven sesquiterpene lactones from Ferreyanthus species

The investigation of two Ferreyanthus species afforded seven germacranolides which have not been isolated previously. Two derivatives of linalol were also present. The structures were elucidated by spectroscopic methods. Chemotaxonomic relationships are briefly discussed.     

Pseudoguaianolides and other sesquiterpene lactones from Gaillardia species

The aerial parts of two Gaillardia species afforded in addition to known sesquiterpene lactones 23 new pseudoguaianolides, two dugaldiolide derivatives and two seco-neopulchellin derivatives. The structures were elucidated by spectroscopic methods. Biogenetic relationships are discussed briefly.     

Tovarol and other germacrane derivatives from Thapsia villosa

Four tovarol, two epoxytovarol (= shiromodiol) and one diepoxytovarol esters were the new germacrane esters isolated from the roots of Thapsia villosa var. minor. The structures of these substances were assigned on the basis of spectral data and chemical correlations with shiromodiol. The acid catalysed rearrangement of tavarol yielded 1(10),4-bulgaradiene-8-ol.     

Isoprenylated resorcinol derivatives from Glycyrrhiza acanthocarpa

The ether extract of leaves and terminal branches of Glycyrrhiza acanthocarpa afforded four new isoprenylated resorcinol derivatives. Two of these are isoprenologues of cannabigerol and cannabigerolic acid.     

Germacranolides from Gochnatia vernonioides

The aerial parts of Gochnatia vernonioides afforded, in addition to dehydrocostus lactone, zaluzanin C and desacetyllaurenobiolide angelate, 14 further sesquiterpene lactones, ten 8, 12-and three 6,12-germacranolides as well as one eudesmanolide and three bisabolene derivatives. The structures were elucidated by spectroscopic methods and by comparing the data with those of closely related compounds. 8α-Angeloyloxytaraxic acid underwent an unusual autocatalysed cyclisation while the usual Cope rearrangement was not observed.     

Acanthospermolides and other constituents from Blainvillea acmella

The aerial parts of Blainvillea acmella afforded, in addition to widespread triterpenes, desacetyl ovatifolin, desacyl grazielic acid tiglate, 8β-[2-methylbutyryloxy]-9β-hydroxy-14-oxo-acanthospermolide, four new germacranolides and seven acanthospermolides. The roots gave ovatifolin, two widespread thiophenacetylenes and two daucane derivatives. Comparison of the data with those of cyclochaenin required a revision of its structure. The structures were elucidated by high field ¹H NMR spectroscopy. Biogenetic relationships and taxonomic aspects are discussed briefly.     

Oxygenated nerolidol derivatives from Artemisia alba

From the aerial parts of Artemisia alba of Calabrian origin, five oxygenated nerolidol derivatives were isolated, two of them bearing hydroperoxyl groups. Structures were elucidated by spectral data and chemical reactions. Acetylation of the major hydroperoxyl constituent afforded a tris-nor aldehydic derivative as a result of loss of acetone from an unstable intermediate perester. An internally consistent set of ¹³C NMR assignments for the natural products and some derivatives is presented.     

Eremophilane derivatives and other constituents from Senecio species

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.     

Structure of cyclohexanone derivatives from Digitalis purpurea

Two cyclohexanone derivatives isolated from the growing tips of Digitalis purpurea were probably 8-oxabicyclo(3.3.1)- 5-hydroxy-4-oxo-non-2-ene (A) and 2-hydroxy-2-(2-hydroxyethyl)-cyclohexanone (B).     

Sesquiterpene lactones and diterpenes from Mikania periplocifolia

The aerial parts of two collections of Mikania periplocifolia gave, in addition to mikanolide, miscandenin and several other known sesquiterpene dilactones related to them, the new dilactones 3β-hydroxy-11βH,13-dihydroisabelin, 11βH,13-dihydrodeoxymikanolide and mikaperiplocolide and three new geranylnerol derivatives.