Showing papers in "Helvetica Chimica Acta in 2010"

Stereochemical Models for Discussing Additions to α,β-Unsaturated Aldehydes Organocatalyzed by Diarylprolinol or Imidazolidinone Derivatives - Is There an '(E)/(Z) -Dilemma'?

Abstract: The structures of iminium salts formed from diarylprolinol or imidazolidinone derivatives and α,β-unsaturated aldehydes have been studied by X-ray powder diffraction (Fig. 1), single-crystal X-ray analyses (Table 1), NMR spectroscopy (Tables 2 and 3, Figs. 2–7), and DFT calculations (Helv. Chim. Acta2009, 92, 1, 1225, 2010, 93, 1; Angew. Chem., Int. Ed.2009, 48, 3065). Almost all iminium salts of this type exist in solution as diastereoisomeric mixtures with (E)- and (Z)-configured +NC bond geometries. In this study, (E)/(Z) ratios ranging from 88 : 12 up to 98 : 2 (Tables 2 and 3) and (E)/(Z) interconversions (Figs. 2–7) were observed. Furthermore, the relative rates, at which the (E)- and (Z)-isomers are formed from ammonium salts and α,β-unsaturated aldehydes, were found to differ from the (E)/(Z) equilibrium ratio in at least two cases (Figs. 4 and 5, a, and Fig. 6, a); more (Z)-isomer is formed kinetically than corresponding to its equilibrium fraction. Given that the enantiomeric product ratios observed in reactions mediated by organocatalysts of this type are often ≥99 : 1, the (E)-iminium-ion intermediates are proposed to react with nucleophiles faster than the (Z)-isomers (Scheme 5 and Fig. 8). Possible reasons for the higher reactivity of (E)-iminium ions (Figs. 8 and 9) and for the kinetic preference of (Z)-iminium-ion formation are discussed (Scheme 4). The results of related density functional theory (DFT) calculations are also reported (Figs. 10–13 and Table 4).

Synthesis, Cytotoxicity and Antibacterial Studies of Novel Symmetrically and Nonsymmetrically 4-(Methoxycarbonyl)benzyl-Substituted N-Heterocyclic Carbene–Silver Acetate Complexes

Abstract: From the reaction of 1H-imidazole (1a), 4,5-dichloro-1H-imidazole (1b), 1H-benzimidazole (1c), 1-methyl-1H-imidazole (1d), and 1-methyl-1H-benzimidazole (1f) with methyl 4-(bromomethyl)benzoate (2), symmetrically and nonsymmetrically 4-(methoxycarbonyl)benzyl-substituted N-heterocyclic carbene (NHC) precursors, 3a–3f, were synthesized. These NHC precursors were then reacted with silver(I) acetate (AgOAc) to yield the NHC–silver acetate complexes (acetato-κO){1,3-bis[4-(methoxycarbonyl)benzyl]imidazol-2-ylidene}silver (4a), (acetato-κO){4,5-dichloro-1,3-bis[4-(methoxycarbonyl)benzyl]-2,3-dihydro-1H-imidazol-2-yl}silver (4b), (acetato-κO){1,3-bis[4-(methoxycarbonyl)benzyl]-2,3-dihydro-1H-benzimidazol-2-yl}silver (4c), (acetato-κO){1-[4-(methoxycarbonyl)benzyl]-3-methyl-2,3-dihydro-1H-imidazol-2-yl}silver (4d), (acetato-κO){4,5-dichloro-1-[4-(methoxycarbonyl)benzyl]-3-methyl-2,3-dihydro-1H-imidazol-2-yl}silver (4e), and (acetato-κO){1-[4-(methoxycarbonyl)benzyl]-3-methyl-2,3-dihydro-1H-benzimidazol-2-yl}silver (4f), respectively. The three NHC–AgOAc complexes 4a, 4c, and 4d were characterized by single-crystal X-ray diffraction. All compounds studied in this work were preliminarily screened for their antimicrobial activities in vitro against Gram-positive bacteria Staphylococcus aureus, and Gram-negative bacteria Escherichia coli using the qualitative disk-diffusion method. All NHC–AgOAc complexes exhibited weak-to-medium antibacterial activity with areas of clearance ranging from 4 to 7 mm at the highest amount used, while the NHC precursors showed significantly lower activity. In addition, NHC–AgOAc complexes 4a and 4b, and 4d–4f exhibited in preliminary cytotoxicity tests on the human renal-cancer cell line Caki-1 medium-to-high cytotoxicities with IC50 values ranging from 3.3±0.4 to 68.3±1 μM.

Three‐Component Reaction of an Isocyanide and a Dialkyl Acetylenedicarboxylate with a Phenacyl Halide in the Presence of Water: An Efficient Method for the One‐Pot Synthesis of γ‐Iminolactone Derivatives

Abstract: The zwitterion, formed from the reaction of an alkyl isocyanide and a dialkyl acetylenedicarboxylate, reacts with phenacyl halides in H2O to produce γ-iminolactone derivatives in high yields. H2O helps to avoid the use of highly toxic and environmentally unfavorable solvents for this conversion.

Neolignans and Caffeoyl Derivatives from Selaginella moellendorffii

Abstract: Ten new phenolic compounds including the six neolignans 1-3 and 6-8 and four caffeoyl derivatives, i.e., myo-inositol 1-caffeate (9), myo-inositol 6-caffeate (10), myo-inositol 5-caffeate (11), and paucine 3'-beta-D-glucopyranoside (12) were isolated from the whole plants of Selaginella moellendorffii (caffeic acid = 3-(3,4-dihydroxyphenyl)prop-2-enoic acid). Their structures were established by spectroscopic and chemical methods.

In‐ and Out‐of‐Cavity Interactions by Modulating the Size of Ruthenium Metallarectangles

Abstract: Cationic (arene)ruthenium-based tetranuclear complexes of the general formula [Ru4(η6-p-cymene)4(μ-N∩N)2(μ-OO∩OO)2]4+ were obtained from the dinuclear (arene)ruthenium complexes [Ru2(η6-p-cymene)2(μ-OO∩OO)2Cl2] (p-cymene=1-methyl-4-(1-methylethyl)benzene, OO∩OO=5,8-dihydroxy-1,4-naphthoquinonato(2−), 9,10-dihydroxy-1,4-anthraquinonato(2−), or 6,11-dihydroxynaphthacene-5,12-dionato(2−)) by reaction with pyrazine or bipyridine linkers (N∩N=pyrazine, 4,4′-bipyridine, 4,4′-[(1E)-ethene-1,2-diyl]bis[pyridine]) in the presence of silver trifluoromethanesulfonate (CF3SO3Ag) (Scheme). All complexes 4–12 were isolated in good yield as CF3SO salts, and characterized by NMR and IR spectroscopy. The host–guest properties of the metallarectangles incorporating 4,4′-bipyridine and (4,4′-[(1E)-ethene-1,2-diyl]bis[pyridine] linkers were studied in solution by means of multiple NMR experiments (1D, ROESY, and DOSY). The largest metallarectangles 10–12 incorporating (4,4′-[(1E)-ethene-1,2-diyl]bis[pyridine] linkers are able to host an anthracene, pyrene, perylene, or coronene molecule in their cavity, while the medium-size metallarectangles 7–9 incorporating 4,4′-bipyridine linkers are only able to encapsulate anthracene. However, out-of-cavity interactions are observed between these 4,4′-bipyridine-containing rectangles and pyrene, perylene, or coronene. In contrast, the small pyrazine-containing metallarectangles 4–6 show no interaction in solution with this series of planar aromatic molecules.

Three New Indole‐Containing Diketopiperazine Alkaloids from a Deep‐Ocean Sediment Derived Fungus Penicillium griseofulvum

Abstract: Three new indole-containing diketopiperazine alkaloids, named variecolorins M–O (1–3), together with the eight known analogues 4–11, were isolated from a deep-ocean sediment-derived fungus, Penicillium griseofulvum. Their structures were determined by analysis of the spectroscopic data. The 2,2-diphenyl-1-picrylhydrazinyl (DPPH) radical-scavenging activities and the cell-proliferation inhibitory activities of the three new compounds 1–3 were investigated.

Experimental and Theoretical Conformational Analysis of 5-Benzylimidazolidin-4-one Derivatives – a ‘Playground’ for Studying Dispersion Interactions and a ‘Windshield-Wiper’ Effect in Organocatalysis

Abstract: The PF6 salts of 5-benzyl-1-isopropylidene- and 5-benzyl-1-cinnamylidene-3-methylimidazolidin-4-ones 1 (Scheme) with various substituents in the 2-position have been prepared, and single crystals suitable for X-ray structure determination have been obtained of 14 such compounds, i.e., 2-10 and 12-16 (rigs. 2-5). In nine of the structures, the Ph ring of the benzyl group resides above the heterocycle. in contact with the cis-substituent at C(2) (staggered conformation A: Figs. 1-3); in three structures, the Ph ring lies above the iminium pi-plane (staggered conformation B; Figs. 1 and 4); in two structures, the benzylic C-C bond has an eclipsing conformation (C; Figs. 1 and 5) which places the Ph ring simultaneously at a maximum distance with its neighbors, the CO group, the N=C-pi-system, and the cis-substituent at C(2) oft lie heterocycle. It is suggested by a qualitative conformational analysis (Fig. 6) that the three staggered conformations of the benzylic C-C bond are all subject to unfavorable steric interactions, so that the eclipsing conformation may lie a kind of 'escape'. State-of-the-art quantum-chemical methods, with large AO basic sets (near the limit) for the single-point calculations, were used to compute the structures of seven of the 14 iminium ions, i.e., 3, 4/12, 5-7, 13, and 16 (Table) in the two staggered conformations, A and B, with the benzylic Ph group above the ring and above the iminium pi-system, respectively. In all cases, the more stable Computed conformer ('isolated-molecule' structure) corresponds to the one present in the crystal (overlay in rig. 7). The energy differences are small (<= 2 kcal/mol) which, together with the result of a potential-curve calculation for the rotation around the benzylic C-C bond of one of the structures, 16 (Fig. 8), suggests that the benzyl group is more or less freely rotating at ambident temperatures. The importance of intramolecular London dispersion (benzene ring in 'contact' with the cis-substituent in conformation A) for DFT and other quantum-chemical computations is demonstrated; the benzyl-imidazolidinones 1 appear to be ideal systems for detecting dispersion contributions between a benzene ring and alkyl or aryl CH groups. Enylidene ions of the type studied herein are the reactive intermediates of enantioselective organocatalytic conjugate additions, Diels-Alder reactions, and many other transformations involving alpha,beta-unsaturated carbonyl compounds. Our experimental and theoretical results are discussed in view of the performance of 5-benzyl-imidazolidinones as enantioselective catalysts.

Phosphomolybdic Acid (PMA) - SiO2 as a Heterogeneous Solid Acid Catalyst for the One-Pot Synthesis of 2H-Indazolo[1,2-b]phthalazine-triones

Abstract: Phosphomolybdic acid (PMA)-SiO 2 was found to be an efficient catalyst for the three-component condensation reaction of phthalhydrazide, 1,3-diketone, and aldehydes to produce 2H-indazolo[1,2-b]phthalazine-triones in excellent yields. The catalyst can be recovered and reused without significant loss of activity.

Three-Component Reaction of Isocyanides and 2-Formylbenzoic Acid with Dibenzylamine Catalyzed by Silica Nanoparticles under Solvent-Free Conditions

Abstract: Reaction of an isocyanide with an iminium ion intermediate, formed by reaction between 2-formylbenzoic acid and dibenzylamine in the presence of silica nanoparticles (silica NP, ca. 42 nm) proceeds smoothly at room temperature to afford isocoumarin (=1H-2-benzopyran-1-one) derivatives in high yields (Scheme 1 and Table 1).

Two New Indole Alkaloids from the Marine‐Derived Bacterium Aeromonas sp. CB101

Abstract: Two new indole alkaloids, arsindolines A and B (1 and 2, resp.), together with six known indole alkaloids, were isolated from a marine-derived bacterium strain CB101, identified as Aeromonas sp. Their structures were established by spectroscopic methods, and their antitumor activities were evaluated by SRB and MTT methods.

Four new terpenoids from Xylaria sp. 101.

Abstract: National Science Fund for Distinguished Young Scholars [30325044]; Chinese Ministry of Education [306010]

A New Isofuranonaphthalenone and Benzopyrans from the Endophytic Fungus Nodulisporium sp A4 from Aquilaria sinensis

Abstract: A new isofuranonaphthalenone, (7R*, 8S*)-3,6,7,8-tetrahydro-4,7,8-trihydroxynaphtho[2,3-c]furan-5(1H)-one (1), and a new benzopyran, (2R*,4R*)-3,4-dilhydro-4-methoxy-2-methyl-2H-1benzopyran-5-ol (2), together with four known related analogs, 3-6, were isolated from the culture of Nodulisporium sp. A4, an endophylic fungus from the stem of Aquilaria sinensis (LOUR.) GILG. The structure of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature reports. The isolated compounds 1-6 were evaluated for their cytotoxic activities against the NCI-H460 and SF-268 tumor cell lines.

New α-Tetralone Galloylglucosides from the Fresh Pericarps of Juglans sigillata.

Abstract: Three new alpha-tetralone galloylghlcosides, 1-3, were isolated from the fresh pericarps of Juglans sigillata (Juglandaceae), together with six known compounds. The structures of the new compounds were determined as 1,2,3,4-tetrahydro-7-hydroxy-4-oxonaphthalen-1-yl 6-O-[(3,4,5-trihydroxyphenyl)carbonyl]-beta-D-glucopyranoside (1), (IS)-1,2,3,4-tetrahydro-8-hydroxy-4-oxonaphthalen-1-yl 6-O-[(3,4,5-trihydroxyphenyl)carbonyl]-beta-D-glycopyranoside (2), and 1,2,3,4-tetrahydro-7,8-dihydroxy-4-oxonaphthalen-1-yl 6-O-[(3,4,5-trihydroxphenyl)carbonyl]-beta-D-glucopyranoside (3), respectively, on the basis of detailed spectroscopic analyses, and acidic and enzymatic hydrolysis. The antimicrobial activities of the isolated compounds 2, 4, and 7-9 were evaluated.

One‐Pot, Three‐Component Synthesis of 1‐(2‐Hydroxyethyl)‐1H‐1,2,3‐triazole Derivatives by Copper‐Catalyzed 1,3‐Dipolar Cycloaddition of 2‐Azido Alcohols and Terminal Alkynes under Mild Conditions in Water

Abstract: A safe, efficient, and improved procedure for the regioselective synthesis of 1-(2-hydroxyethyl)-1H-1,2,3-triazole derivatives under ambient conditions is described. Terminal alkynes reacted with oxiranes and NaN3 in the presence of a copper(I) catalyst, which is prepared by in situ reduction of the copper(II) complex 4 with ascorbic acid, in H2O. The regioselective reactions exclusively gave the corresponding 1,4-disubstituted 1H-1,2,3-triazoles in good to excellent yields. This procedure avoids the handling of organic azides as they are generated in situ, making this already powerful click process even more user-friendly and safe. The remarkable features of this protocol are high yields, very short reaction times, a cleaner reaction profile in an environmentally benign solvent (H2O), its straightforwardness, and the use of nontoxic catalysts. Furthermore, the catalyst could be recovered and recycled by simple filtration of the reaction mixture and reused for ten consecutive trials without significant loss of catalytic activity. No metal-complex leaching was observed after the consecutive catalytic reactions.

A New Dimeric Alkaloid from the Leaf of Psychotria calocarpa

Abstract: Psychotriasine was isolated from the leaves of Psychotria calocarpa (Rubiaceae) The structure was established by spectroscopic methods including 2D-NMR analysis To the best of our knowledge, psychotriasine is the first example of a dimeric tryptamine-related alkaloid that contains a free N(alpha)-methyliryptamine unit in the molecule

Two New Metabolites, Epoxydine A and B, from Phoma sp.

Abstract: The new compounds, epoxydines A and B (1 and 2, resp.), along with the known and related metabolites, 3–6, were isolated from the fungal endophyte Phoma sp. The structures of the new compounds were elucidated by detailed spectroscopic analysis, and the relative configuration of 1 was confirmed by ROESY experiments. Preliminary studies indicated that compounds 2–5 possess good antibacterial, antifungal, and algicidal properties. Similarly, compound 1 showed antifungal and algicidal, and compound 6 antibacterial and algicidal properties.

Monoterpenoids from the fruit of Gardenia jasminoides.

Abstract: Eight new monoterpenoids, jasminoside J (1), jasminoside K (2), 6′-O-trans-sinapoyljasminoside B (3), 6′-O-trans-sinapoyljasminoside L (4), jasminosides M–P (5–8), together with three known analogues, jasminoside C (9), jasminol E (10), and sacranoside B (11), were isolated from the fruit of Gardenia jasminoidesEllis (Rubiaceae). Their structures were elucidated by spectral and chemical methods.

Revisiting the Hinsberg Reaction: Facile and Expeditious Synthesis of 3‐Substituted Quinoxalin‐2(1H)‐ones under Catalyst‐Free Conditions in Water

Abstract: Substituted benzene-1,2-diamine reacted with various α-keto esters at 50° under mild conditions for 15 min using H2O as reaction medium, providing a variety of 3-substituted quinoxalinone derivatives in excellent yields. The reaction was instantaneous, and products were isolated by simple filtration.

Catalytic Performance of Ruthenium‐Supported Ionic‐Liquid Catalysts in Sustainable Synthesis of Macrocyclic Lactones

Abstract: Thirteen- to eighteen-membered lactones were synthesized by ring-closing olefin-metathesis reactions of bis-olefins with heterogeneous Grubbs-supported ionic-liquid catalysts (SILCs), in which homogeneous Grubbs catalysts were confined in pores of alumina with the aid of an ionic liquid. The Grubbs-SILCs exhibited higher catalytic performance than their homogeneous counterparts and could be repeatedly recovered by simple filtration and re-used several times.

Seven Novel Linear Polyketides from Xylaria sp. NCY2

Abstract: National Science Fund for Distinguished Young Scholars [30325044]; Key Grant of Chinese Ministry of Education [306010]; 863 Program [2006AA10A202]

Pronounced Catalytic Activity of Manganese(III)–Schiff Base Complexes in the Oxidation of Alcohols by Tetrabutylammonium Peroxomonosulfate

Abstract: A novel and practical catalytic method for efficient and highly selective oxidation of a wide range of benzylic, allylic, aliphatic, primary, and secondary alcohols to the corresponding aldehydes and ketones using tetrabutylammonium peroxomonosulfate catalyzed by tetradentate Schiff base–MnIII complexes has been developed. Electron-deficient and hindered alcohols required longer reaction times for oxidation in this catalytic system. The electron-poor and hindered salicylidene ring of the ligand enhanced the catalytic activity and stability of Mn catalysts. The desired turnover numbers obtained in the oxidation reactions indicated the high efficiency and relative stability of these simple Schiff base complexes in this catalytic system.

Specific Deuteration in Patuletin and Related Flavonoids via Keto–Enol Tautomerism: Solvent‐ and Temperature‐Dependent 1H‐NMR Studies

Abstract: An H/D exchange process in patuletin (1) and its derivatives in D-donor solvents (e.g., CF3COOD), which occurs regioselectively at C(8) was observed for the first time during NMR studies. The effect of substituents and temperature on the deuteration of various flavonoids (see Fig. 1) which include apigenin, chrysin, galangin, kaempferol, luteolin, morin, myricetin, patuletin, patulitrin, and quercetin, as well as derivatives of patuletin was examined extensively under NMR conditions. The rate constant of deuteration at C(8) of patuletin (1) and two flavones, luteolin (3) and apigenin (12), was also determined in CF3COOD. The D-atom was introduced into the flavonoids via a keto–enol tautomerism (Scheme 1). During these studies, monodeuterated patuletin was also obtained as a new compound. The examined flavonoids have been reported to possess significant pharmacological activities, and their deuterated derivatives would be of importance for the identification and quantification of these compounds in biological matrices.

New Lactone and Xanthone Derivatives Produced by a Mangrove Endophytic Fungus Phoma sp. SK3RW1M from the South China Sea

Abstract: A new lactone, 1,8-dihydroxy-10-methoxy-3-methyldibenzo[b,e]oxepine-6,11-dione (1), and two new xanthones, 1-hydroxy-8-(hydroxymethyl)-6-methoxy-3-methyl-9H-xanthen-9-one (2) and 1-hydroxy-8-(hydroxymethyl)-3-methoxy-6-methyl-9H-xanthen-9-one (3), were isolated from a mangrove endophytic fungus Phoma sp. SK3RW1M collected from the South China Sea. This is the first report on xanthone derivatives isolated as secondary metabolites from Phoma species. Their structures were elucidated by spectroscopic methods, mainly 1D- and 2D-NMR techniques, and the structure of compound 2 was confirmed by X-ray crystallography. Cytotoxicity assays showed that compounds 1–3 were inactive against KB and KBv200 cells.

11- and 4′-Epimers of Chaetomugilin A, Novel Cytostatic Metabolites from Marine Fish-Derived Fungus Chaetomium globosum

Abstract: 11- and 4′-epichaetomugilin A were isolated from a strain of Chaetomium globosum that was originally isolated from the marine fish Mugil cephalus. 11-Epichaetomugilin A is the first compound to have an opposite absolute configuration at C(11) to that of other azaphilones isolated to date. Their absolute configurations were elucidated on the basis of spectroscopic analyses, including 1D- and 2D-NMR techniques, and some chemical transformations. 11-Epichaetomugilin A weakly inhibited the growth of cultured P388 cells and HL-60 cells (IC50 88.9 and 66.7 μM, resp.).

Total Synthesis of the Biologically Active, Naturally Occurring 3,4‐Dibromo‐5‐[2‐bromo‐3,4‐dihydroxy‐6‐(methoxymethyl)benzyl]benzene‐1,2‐diol and Regioselective O‐Demethylation of Aryl Methyl Ethers

Abstract: 3,4-Dibromo-5-[2-bromo-3,4-dihydroxy-6-(methoxymethyl)benzyl]benzene-1,2-diol (2), a natural product, has been synthesized for the first time starting from (3-bromo-4,5-dimethoxyphenyl)methanol (5) in five steps and with an overall yield of 34%. The reaction of some methoxymethyl-substituted aryl methyl ethers with BBr3, followed by the addition of MeOH, afforded the corresponding methoxymethyl-substituted arylphenols in high yields.

Synthesis of Novel Polycyclic Indole‐Annulated Thiopyranocoumarin Derivatives via Domino Knoevenagel–Hetero‐Diels–Alder Reaction in Aqueous Media

Abstract: An efficient synthesis of polycyclic indole derivatives is achieved via domino Knoevenagel–hetero-Diels–Alder reaction of O-acrylated salicylaldehyde derivatives with dihydroindole-2-thiones in H2O as solvent. The products are formed in good-to-excellent yields with high regio- and stereoselectivity.

New Guaipyridine Sesquiterpene Alkaloids from Artemisia rupestris L.

Abstract: Three new guaipyridine sesquiterpene alkaloids, rupestine A, B, C (1-3, resp.), and the new norsesquiterpne alkaloid rupestine D (4) were obtained from the flowers of Artemisia rupestris L. Their structures were elucidated on the basis of sepectroscopic data and by comparison with those of the related compounds reported in the literature. In addition, the absolute configurations of 2 and 4 were determined by single-crystal X-ray diffraction analyses. © 2010 Verlag Helvetica Chimica Acta AG.

Terpenoids from Roots of Chloranthus spicatus

Abstract: Five new terpenoids, including four eudesmane-type sesquiterpenoids, 1–4, and one labdane-type diterpenoid, 6, together with ten known compounds, were isolated from the roots of Chloranthus spicatus. The structures and their relative configurations were mainly established by 1D- and 2D-NMR spectra, and MS experiments.

Copper‐Catalyzed Ritter‐Type Reaction of Unactivated Alkenes with Dichloramine‐T

Abstract: It was shown that dichloramine-T (1) reacted with cyclohexene in acetonitrile to give N1-(2-chlorocyclohexyl) amidine 2a and N-(2-chlorocyclohexyl)acetamide (3) via the competitive addition of acetonitrile and N-chloro-N-tosylamino anion to cyclohexenechloronium ion. This reaction can be catalyzed by Cu(OAc)2, primarily affording 2a. Furthermore, the resulting 2a can be cyclized to benzimidazol 14a in good yield by treating with KOH in dioxane.

Eremophilane Sesquiterpenoids from Ligularia fischeri

Abstract: ) Department of Chemical Engineering, Inha University, Incheon 402-751, Korea(phone: þ82-32-8607470; fax: þ82-32-8720959; e-mail: rowkho@inha.ac.kr)A novel eremophilane dimer, named as fischelactone, and a new sesquiterpene lactam, eremophila-1(10),7(11),8-triene-12,8-lactam, along with ten known compounds, were isolated from the roots ofLigularia fischeri. Their structures were established by means of spectroscopic analyses (EI-MS, HR-ESI-MS, IR, and 1D- and 2D-NMR data) and X-ray diffraction study.