Two new sesquiterpene lactones from Ixeris chinensis

Phytochemical investigation of Ixeris chinensis NAKAI (Asteraceae) has resulted in the isolation of a new guaianolide-type sesquiterpene lactone, ixerochinolide (1) as well as the related glucoside, ixerochinoside (2). In addition, the known guaianolides, 8beta-hydroxy-3-oxo-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8beta-hydroxydehydrozaluzanin), 8beta,15-dihydroxy-2-oxo-guaia-1(10),3,11(13)-trien-5alpha,6beta,7alphaH-12,6-olide (lactucin), 3beta,8alpha,10alpha-trihydroxy-guaia-4(15),11(13)-dien-1alpha,5alpha,6beta,7alphaH-12,6-olide (10alpha-hydroxy-10,14-dihydro-desacylcynaropicrin) and 3beta-D-glucopyranosyloxy-8beta-(p-hydroxyphenylacetyloxy)-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8-epicrepioside) were identified. The structures were determined on the basis of spectral analyses, especially 1- and 2D NMR. Compound 1 exhibited significant cytotoxicity against human PC-3 tumor cells.     

ααTwo new eudesmane sesquiterpenes from Lactuca sativa var. anagustata L

Two new eudesmane sesquiterpene lactones were isolated from the stalk of Lactuca sativa var.anagustata L and their structureswere elucidated by means of spectroscopic methods,including 2D NMR(~1H-~1H COSY,HMBC and NOESY) as 1β-O-β-D-glucopyranosyl-4α-hydroxyl-5α,6β,11βH-eudesma-12,6α-olide(1) and 1β-hydroxyl-15-O-(p-methoxyphenylacetyl)-5α,6β,11βH-eudesma-3-en-12,6α-olide(2).     

Two New Eremophilenolides from Ligularia sagitta

Chemical investigation of L.sagitta afforded two new eremophilenolides, which were identified as 6β-angeloyloxy-10β-hydroxy-8 β-methoxy-eremophil-7(11)-en-12, 8α-olide (1) and 6β, 8β-dimethoxy-10β-hydroxy-eremophil-7(11)-en-12, 8α-olide (2). Their structures were estab- lished by spectroscopic methods including 2D NMR experiments.     

Labdane diterpenes from the rhizomes of Hedychium coronarium

A new labdane diterpenoid, (E)-labda-8(17),12-dien-15,16-olide (1) together with eight known compounds, coronarin D (2), coronarin D methyl ether (3), coronarin D ethyl ether (4), isocoronarin D (5), coronarin B (6), labda-8(17),11,13-trien-15,16-olide (7), (E)-labda-8(17),12-diene-15,16-dial (8) and 16-hydroxylabda-8(17),11,13-trien-15,16-olide (9), are isolated from the rhizomes of Hedychium coronarium. Compounds 2-4, 5 and 9 are isolated as mixtures of C-15, C-14 and C-16 epimers, respectively. Their structures are determined on the basis of their spectroscopic data. The epimeric mixtures of 2 and 3 have not been reported before. Some of them were evaluated for their cytotoxicity.     

Sesquiterpenoids from Ligularia virgaurea spp. oligocephala

Four novel eremophilane-type sesquiterpene lactones, 6β,10α-dihydroxy-1-oxoeremophila-7(11),8(9)-dien-12,8-olide (1), 6β-acetyl-2-oxoeremophila-1(10),7(11), 8(9)-trien-12,8-olide (2), 6β,8β-diacetyl-2-oxoeremophila-1(10),7(11)-dien-12,8-olide (3), dimeric eremophilane ligulolide B (5), and known sesquiterpenoid, 6β,8α-diacetyleremophila-1(10),7(11)-dien-12,8-olide (4), were isolated from an extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure of 1 was confirmed by NMR spectra and single crystal X-ray crystallography investigation, as well as 2, 3, and 5 were elucidated by spectroscopic methods including 1D and 2D NMR spectra. A discussion of biogenesis of 5 was described. Cytotoxicities of compound 1 were measured in vitro against selected cancer cells human promyelocytic leukemia (HL-60), human ovarian (HO-8910) and human lung epithehial (A-549).     

Epoxy lactones by photooxidative rearrangement of 6β-acetoxyvouacapane

The first study of photooxidation reaction of 6β-acetoxyvouacapane isolated from Caesalpinia platyloba is reported. The reaction yielded four new epoxy lactones, 6β-acetoxy-15,16α-epoxy-13-spirocassa-12,16-olide, 6β-acetoxy-15,16β-epoxy-13-spirocassa-12,16-olide, 6β-acetoxy-12,13β-epoxycassa-16,12-olide and 6β-acetoxy-12,13α-epoxycassa-16,12-olide. All the structures were supported by 1D and 2D NMR spectroscopy as well as mass spectrometry. The stereochemistry was established on the base of single crystal X-ray diffraction.     

Guaianolide Sesquiterpene Lactones from Centaurothamnus maximus

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), and quercetagetin-3,6-dimethyl ether-4’-O-β-d-pyranoglucoside (9). Chemical structures were elucidated using spectroscopic techniques, including High Resolution Fast Atom Bombardment Mass Spectrometry (HR-FAB-MS), 1D NMR; ¹H, ¹³C NMR, Distortionless Enhancement by Polarization Transfer (DEPT), and 2D NMR (¹H-¹H COSY, HMQC, HMBC) analyses. In addition, a biosynthetic pathway for compounds 1–9 is proposed. The chemotaxonomic significance of the reported sesquiterpenoids and flavonoids considering reports from other Centaurea species is examined.     

Complete assignments of 1H and 13C NMR spectral data for three sesquiterpenoids from Inula helenium

The complete assignments of all the (1)H and (13)C NMR signals of three sesquiterpene lactones, 4-oxo-5(6),11-eudesmadiene-8,12-olide (1), 4-oxo-11-eudesmaene-8,12-olide (2) and (1(10)E)-5beta-Hydroxygermacra-1(10),4(15),11-trien-8, 12-olide (3), were carried out by various 2D NMR experiments. Compounds 1-3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor-sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The (13)C-NMR data of compound 3 was also reported for the first time.     

大叶橐吾中三个新的艾里莫芬型倍半萜

从大叶橐吾的根部分离得到三个新的艾里莫芬型倍半萜(1, 2和3), 经多种波谱方法和单晶X射线衍射确定它们的结构分别为: 6α,15β-环氧-8β-羟基-艾里莫芬-7(11)-烯-8α,12-内酯(1), 7-乙酰基-13β-羧酸-6(7)-烯-降-艾里莫芬烷(2), 艾里莫芬-7(11)-烯-6α,15β-内酯(3). 此外, 对化合物1进行了抗菌和抗癌活性测试.     

Regulated expressions of MMP-2, -9 by diterpenoids from Euphorbia formosana Hayata

Two new abietane type diterpenoids, namely seco-helioscopinolide (1) and 3b,7b-dihydroxy-ent-abieta-8,13-diene-12,16-olide (2) were isolated from the aerial parts of Euphorbia formosana Hayata together with helioscopinolide A (3), helioscopinolide B (4), helioscopinolide C (5) and ent-(5b,8a,9b,10a,12a)-12-hydroxyatis-16-ene-3,14-dione (6). The structures of compounds 1-6 were elucidated by analyzing their spectroscopic data and comparison with the literature. Further biological tests by gelatin zymographic analysis revealed that 3-5 significantly up-regulated the expressions and activation of MMP-2 and -9 in human fibrosarcoma cell line HT1080.     

New cembranolide analogues from the formosan soft coral Sinularia flexibilis and their cytotoxicity

Using a bioactivity-guided fractionation procedure, five cembranolides, 11-epi-sinulariolide acetate (1), 11-dehydrosinulariolide (2), sinulariolide (3), dihydrosinularin (4), and 3,4:8,11-bisepoxy-7-acetoxycembra-15(17)-en-1,12-olide (5), along with two nucleosides, 2'-deoxyadenosine and thymidine, were isolated from the Formosan soft coral Sinularia flexibilis. Moreover, 7,8-epoxy-11-epi-sinulariolide acetate (1a), 11-sinulariolide acetate (3a), dihydrosinulariolide (3b), 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-en-1,12-olide (3c), 11-acetoxyl-15(17)-dihydrosinulariolide (3d), 7,8-epoxy-11-sinulariolide acetate (3e), and 3,4:8,11-bisepoxy-7-hydroxycembra-15(17)-dihydro-1,12-olide (3f) were derived from compounds 1 and 3, respectively. These structures were deduced on the basis of physical and chemical evidence. Among them, 1a, 3d, 3e, and 3f are new cembranolide analogues. The structure of compound 1 was further confirmed by X-ray analysis. In addition, the isolated cembranolides and the analogues under went a cytotoxicity assay, and the structure-activity relationship (SAR) of these compounds was studied.     

Synthesis of novel L-2',3'-dideoxy-2'-trifluoromethyl-4'- thiocytidines from alpha-trifluoromethyl-alpha,beta-unsaturated ester

A short and efficient synthesis of L-2',3'-dideoxy-2'-trifluoromethyl-4'-thiocytidines is described. (2R,4S/2S,4S)-5-(tert-Butyldimethylsiloxy)-2-trifluoromethylpentan-4-olide (3a and 3b) are prepared from alpha-trifluoromethyl-alpha,beta-unsaturated ester (1) in three steps and converted to compounds 6a and 6b. The corresponding 1-O-acetyl derivatives 8a and 8b were obtained via the usual Pummerer rearrangement from 6a and 6b in two steps, which were in turn used to synthesize L-4'-thiocytidines 10a and 10b.     

Constituents of a fern, Diplazium subsinuatum. III. Four new hopane-triterpene lactone glycosides

From a whole plant of a fern, Diplazium subsinuatum, three new hopane-triterpene lactone glycosides, diplaziosides V-VII (1-3), were isolated, together with a new monoacetyl derivative (4) of diplazioside VII (3). Compounds 1-3 were defined as the respective 3-O-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosides of 3beta,24-dihydroxyhopan-28,22-olide (1), of 3beta,17,24-trihydroxyhopan-28,22-olide (2), and of (22R)-3beta,24,30-trihydroxyhopan-28,22-olide (3), and 4 as the 6"-O-acetate of 3, respectively, on the basis of spectral evidence. 1-3 are new in their glycoside structures but also in their triterpene structures. Furthermore, in compounds 1-4, the coupling between the 24-hydroxy proton and one of the 24-methylene protons showed a very large J-value (11.4 Hz); based on this 1H-NMR evidence, etc., preferred conformations of the 24-hydroxymethylene groups in 1-4 are also inferred. In a similar manner, 1H-NMR coupling patterns of the 24-hydroxymethylene in the monoglucoside (2a) and aglycone (2b), derived from 2, are also reported and discussed here.     

Sesquiterpene lactones from Saussurea alata

Two new guaianolides, namely, 3beta,8alpha-dihydroxy-13-methoxyl-4(14),10(15)-dien-(1alphaH,5alphaH,6beta H,11betaH)-12,6-olide (1) and 3beta,8alpha-dihydroxy-13-methoxyl-4(14),10(15)-dien-(1alphaH,5alphaH,6beta H,11alphaH)-12,6-olide (2), together with six known guaianolides, 8-hydroxyzaluzanin C, austricin, chlorojanerin, cynaropicrin, chlorohyssopifolin E and chlorohyssopifolin A were isolated from the aerial parts of Saussurea alata. The structures were established mainly based on spectral analysis, especially 2D NMR techniques.     

Synthese von racemischen Aminozuckersäure-lactonen: xylo- und lyxo-2,3-Diacetylamino-5-acetoxypentan-4-olid und -2,3,5-Triacetylaminopentan-4-olid

Synthesis of Racemic Aminosugar Lactones: xylo- and lyxo-2,3-Diacetylamino-5-acetoxypentan-4-olide and -2,3,5-Triacetylaminopentan-4-olide Starting with 5-hydroxy-2-penten-4-olide ( 1 ), the tricyclic intermediate 4 was prepared via the chloride 2 , the acyl azide 3 , and an intramolecular nitrene addition (Scheme 3). Azide ion opened the aziridine ring in 4 at C(α) to give 5 , which was transformed via 7 into one of the title compounds, the triacetylated diamino-hydroxy-lactone 13 (Scheme 4). An alternative conversion of 4 into 13 involved the synthesis of the N-acetylaziridine 10 , the opening of the 3-ring of 10 with N to form 12 , and a final reductive acetylation (Scheme 5). The third N-substituent was introduced at C(δ) of 13 by the following sequence: hydrolysis of the AcO group (→ 14 ), mesylation (→ 15 ), substitution by N (→ 16 ), and reductive acetylation to yield the other title compound, the triacetylated triaminolactone 17 (Scheme 6). Since the ring opening of aziridines by nucleophiles occurs by inversion, the primary products 5a and 12a of the N reactions as well as the substances derived from them, i.e. 6a , 7a , and 13a - 17a , have the xylo-configuration ( a -series). Under some of the reaction conditions, the primary xylo-products suffered a partial epimerization at C(α) to yield mixtures containing the corresponding lyxo-products ( b -series): The equilibrium between the xylo- and lyxo-isomers was estimated for 5a/5b =1:3, 12a/12b =5:2, 13a/13b =3:1, and 16a/16b =2:1. Since the stereoisomers of the a - and the b -series were always separable, the other lyxo-products, i.e. 6b , 7b , could be prepared from 5b and 12b .     

Structural determination of three new eudesmanolides from Inula helenium

Ten sesquiterpenens were isolated from Inula helenium. Among them, three eudesmanolides: 15-hydroxy-11betaH-eudesm-4-en-8beta,12-olide (1), 3alpha-hydroxy-11betaH-eudesm-5-en-8beta,12-olide (2) and 2beta, 11alpha-dihydroxy-eudesm-5-en-8beta,12-olide (3) are new compounds. Their chemical structures were determined by spectral methods including 2D NMR.     

Identification and Synthesis of New γ-Lactones from Tuberose Absolute (Polianthes tuberosa)

Six unsaturated γ-lactones, (Z)-5-octen-4-olide ( 1 ), (Z)-5-decen-4-olide ( 2 ).(Z)-6-nonen-4-olide ( 3 ), (Z)-6-dodecen-4-olide ( 4 ), (Z, Z)-6,9-dodecadien-4-olide ( 5 ), and tuberolide ( 6 ) have been identified for the first time in tuberose absolute (from Polianthes tuberosa L.). All structures were corroborated by synthesis and all, except 3 and 4 , are new.

1 The name ‘tuberolactone’ has been suggested for (Z, Z)-2,7-decadien-5-olide [1]. We propose the name ‘tuberolide’ for the bicyclic lactone 6 . (IUPAC name (1R*,5S*,Z)-6-(2′-pentenyl)-2-oxabicyclo[3.3.0]octan-3-one).

An improved method for the stereoselective synthesis of (±)-cis-bicyclo [4.3.0]-non-3-en-7-one ( 23 ) by an AlCl₃-catalyzed Diels-Alder reaction is reported.     

A new eremophilane-type sesquiterpene from Ligularia virgaurea

A new eremophilane-type sesquiterpene,1α,8β,10β-trihydroxy-6β-(2-methylacryloyl)oxyeremophil-7(11)-en-8α,12-olide, was isolated from the roots of Ligularia virgaurea.Its structure was established on the basis of various spectroscopic analyses, including the 1D,2D NMR techniques and HR-ESI-MS.     

Three new compounds from Sarcandra glabra

One new sesquiterpene lactone,1 α,8 α,9 α-trihydroxyeudesman-3(4),7(11)-dien-8 β,12-olide(1) and two new phenylpropanoidsubstituted catechin glycosides,glabraoside C(2) and glabraoside D(3) were isolated from the whole plant of Sarcandra glabra. Their structures were established by the analyses of spectral and chemical evidences.     

Wedelolides A and B: novel sesquiterpene delta-lactones, (9R)-eudesman-9,12-olides, from Wedelia trilobata

Two new sesquiterpene lactones, wedelolides A (1) and B (2), were isolated by bioassay-guided fractionation from the leaves of Wedelia trilobata, together with known trilobolides 6-O-isobutyrate (3) and 6-O-methacrylate (4). The compounds 1 and 2 were the first examples of an unprecedented framework: a novel sesquiterpene delta-lactone, (9R)-eudesman-9,12-olide. The structures of the antimalarial wedelolides A (1) and B (2) were determined on the basis of MS and 2D NMR spectral analysis. The absolute configuration of eight carbon stereocenters of compounds 1 and 2 was determined to be 1S,4S,5S,6R,7S,8S,9R,10S by mean of auxiliary chiral MTPA derivatives.