Showing papers in "Helvetica Chimica Acta in 2014"

Synthesis of Imidazo[1,2‐a]pyridines Using Fe3O4@SiO2 as an Efficient Nanomagnetic Catalyst via a One‐Pot Multicomponent Reaction

Abstract: A one-pot multicomponent synthesis of imidazo[1,2-a]pyridine derivatives by using pyridin-2-amines, aldehydes, and terminal alkynes in the presence of a catalytic amount of silica-supported iron oxide (Fe3O4@SiO2) nanoparticles in refluxing EtOH in good-to-excellent yields is reported.

Purification of Enantiomeric Mixtures in Enantioselective Synthesis: Overlooked Errors and Scientific Basis of Separation in Achiral Environment

Abstract: The syntheses of optically active compounds (whether of pharmaceutical or synthetic importance, or as promising candidates as chiral ligands and auxiliaries in asymmetric syntheses) result in the formation of a mixture of products with one enantiomer predominating. Usually, the practice is to use standard open-column chromatography for the first purification step in an enantioselective synthesis; the workup of the reaction product by crystallization or achiral chromatography would mask the real efficiency of the enantioselective methodology, since enantiomeric ratio (er) of the product may change by any of these methods. Most of the synthetic organic chemists are aware of the influence of crystallization on the er value. Majority of synthetic organic chemists are, however, not aware, while employing standard chromatography, that there may be an increase or decrease of er value. In other words, an undesired change in er goes unnoticed when such a mixture of enantiomers is isolated by chromatography on an achiral-phase because of the prevalent concept of basic stereochemistry. Such unnoticed errors in enantioselective reactions may lead to misinterpretations of the enantioselective outcome of the synthesis. The scientific issue is, what is the difference between a racemic and nonracemic mixture in achiral environment (e.g., achiral-phase chromatography) that leads to enantiomeric enrichment, amounting to separation of one particular enantiomer? There are sporadic reports on enantiomer separation of nonracemic mixtures in an achiral environment particularly from the scientists working in analytical chemistry. To cover/discuss all these reports is out of the scope of this article. The aim of the present report is to draw attention to the following points: i) How should the synthetic organic chemists and analytical chemists take care of the unexpected separation of enantiomers from nonracemic mixtures in a totally achiral environment? ii) What are the technical terms used in recent literature? iii) The requirement of revisiting definitions/terms (introduced in recent years, in particular) to describe such separations of enantiomers in light of prevalent scientific/chemical terminology used in the ‘language of chemistry’, the text book concept, and IUPAC background. iv) To propose logical scientific terminology or phrases for explaining the possible mechanism of separation under these conditions. v) To discuss briefly the concept/possibile phenomenon responsible for these enantioselective effects. It is also attempted to explain the effect of change of physical parameters influencing the separation from nonracemic mixture in achiral-phase chromatography.

Terminology Related to the Phenomenon ‘Self-Disproportionation of Enantiomers’ (SDE)

Abstract: Terms related to the phenomenon self-disproportion of enantiomers (SDE) are discussed, particularly with respect to recently suggested alternative terms. Of the numerous terms proffered to describe this phenomenon, it is recommended that the acronym SDE be retained based on its qualities and the fact that its perceived shortcomings are invalid. The term can be readily applied to any process that exhibits the phenomenon of transforming a scalemic sample into fractions containing different enantiomeric compositions in comparison to the enantiomeric composition of the starting sample, and is not restricted solely to chromatographic occurrences. Chromatographic observations, though, can be specifically described by the term enantiomer self-disproportionation over achiral chromatography (ESDAC). Use of the term homochiral in concert with its intended original meaning is also advocated.

Anthraquinone Derivatives and an Orsellinic Acid Ester from the Marine Alga-Derived Endophytic Fungus Eurotium cristatum EN-220

Abstract: Cultivation of the fungal strain Eurotium cristatum EN-220, an endophyte obtained from the marine alga Sargassum thunbergii, resulted in the isolation of one new anthraquinone glycoside, 3-O-(alpha-D-ribofuranosyl)questinol (1) and one new orsellinic acid ester, cristatumside A (2), together with three known aromatic glycosides, 3-O-(alpha-D-ribofuranosyl)questin (3), isotorachrysone 6-O-alpha-D-ribofuranoside (4), and asperflavin ribofuranoside (5), as well as three anthraquinone derivatives, asperflavin (6), eurorubrin (7), and (+)-variecolorquinone A (8). The structures of these compounds were determined by extensive analysis of their spectroscopic data, as well as by their comparison with those in the literature. Each of the isolated compounds was evaluated for its antimicrobial activity and brine shrimp lethality.

Concerted vs. Non‐Concerted 1,3‐Dipolar Cycloadditions of Azomethine Ylides to Electron‐Deficient Dialkyl 2,3‐Dicyanobut‐2‐enedioates

Abstract: The quantum-chemical calculations of the thermal ring opening of 1-methyl-2,3-diphenyl- and 1,2,3-triphenylaziridine with formation of the corresponding azomethine ylides of S-, U-, and W-type as well as their cycloaddition to dimethyl acetylenedicarboxylate (DMAD) and dimethyl 2,3-dicyanobut-2- enedioate, were performed at the DFT B3LYP/6-31G(d) level of theory with the PCM solvation model. The calculations are in complete accordance with experimental results and explain the switch from the concerted to the non-concerted pathway depending on substituents in the dipolarophile and the ylide. It was found that strong electron-withdrawing substituents in dipolarophiles, such as in dialkyl dicyanobutenedioates, significantly reduce the barrier for the formation of zwitterionic intermediates in the reaction of azomethine ylides with such dipoles. This can render the stepwise cycloaddition competitive with the concerted one. However, the concertedness of the cycloaddition even to dipolarophiles with several electron-withdrawing substituents is governed by a fine balance of electronic and steric effects in both ylide and dipolarophile counterparts. The hypothesis that introduction of substituents in the azo- methine ylide that destabilize the positive charge in a corresponding zwitterion will favor the concerted cycloaddition even with dialkyl dicyanobutenedioates was tested theoretically and experimentally.

Tris‐cyclometalated Iridium(III) Complexes with Three Different Ligands: a New Example with 2‐(2,4‐Difluorophenyl)pyridine‐Based Complex

Abstract: An iridium(III) complex comprising three different cyclometalated phenylpyridine-based ligands was designed and synthesized. Interestingly, mixed-ligand complexes could be obtained by using a simple and straightforward procedure. A tris(heteroleptic) IrIII complex was obtained as a mixture of stereoisomers that could not be separated. Photophysical properties of the tris(heteroleptic) complex was investigated by UV/VIS absorption and luminescence spectroscopy, and compared with those of the parent homoleptic complexes. Modelling by time-dependent density functional theory (TD-DFT) was also performed to elucidate the nature and the location of the excited state, and to support the experimental results.

Secondary Metabolites from the Endophytic Fungus Xylaria cubensis

Abstract: Seven new metabolites, including three sesquiterpenoids, 10-hydroxythujopsene (1), akotriol (2), and xylaritriol (3), one diterpenoid, cubentriol (4), one aliphatic derivative, akoenic acid (5), one alkaloid, akodionine (6), and one isocoumarin, akolitserin (7), together with seven known compounds, 8–14, were isolated from the AcOEt-soluble fraction of the fermentation broth of the endophytic fungus Xylaria cubensis, derived from the leaves of Litsea akoensis Hayata (Lauraceae). Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR experiments, and by HR-ESI-MS mass spectrometry. Among the isolates, (−)-(R)-7-hydroxymellein showed IL-6 inhibitory activity with an IC50 value of 9.41 μM.

1,3‐Dipolar Cycloadditions of Ethyl 2‐Diazo‐3,3,3‐trifluoropropanoate to Alkynes and [1,5] Sigmatropic Rearrangements of the Resulting 3H‐Pyrazoles: Synthesis of Mono‐, Bis‐ and Tris(trifluoromethyl)‐Substituted Pyrazoles

Abstract: The 1,3-dipolar cycloadditions of ethyl 2-diazo-3,3,3-trifluoropropanoate with electron-rich and electron-deficient alkynes, as well as the van AlphenHuttel rearrangements of the resulting 3H-pyrazoles were investigated. These reactions led to a series of CF3-substituted pyrazoles in good overall yields. Phenyl- and diphenylacetylene proved to be unreactive, but, at high temperature, the diazoalkane and phenylacetylene furnished a cyclopropene derivative. As expected, the 1,3-dipolar cycloaddition to the ynamine occurred much faster than those to electron-deficient alkynes. With one exception, all cycloadditions proceeded with excellent regioselectivities. The [1,5] sigmatropic rearrangement of the primary 3H-pyrazoles provided products with shifted acyl groups; products resulting from the migration of a CF3 group were not detected. In agreement with literature reports, this rearrangement occurs faster with 3H-pyrazoles bearing electron-withdrawing substituents.

Sesquiterpenoids from the Fruits of Alpinia oxyphylla and Their Anti-Acetylcholinesterase Activity

Abstract: Fourteen sesquiterpenoids were isolated from the fruits of Alpinia oxyphylla Miq. Their structures were elucidated based on NMR analyses (1H, 13C, DEPT, 1H,1H-COSY, HMQC, HMBC, and NOESY) and identified as 12-nornootkaton-6-en-11-one (3), (+)-(3S,4aS,5R)-2,3,4,4a,5,6-hexahydro-3-isopropenyl-4a,5-dimethyl-1,7-naphthoquinone (5), nootkatene (6), 9β-hydroxynootkatone (7), 2β-hydroxy-δ-cadinol (8), 4-isopropyl-6-methyl-1-tetralone (11), oxyphyllone E (12), oxyphyllone D (13), oxyphyllanene B (15), oxyphyllone A (16), oxyphyllol E (17), (9E)-humulene-2,3;6,7-diepoxide (18), mustakone (20), and pubescone (21). Among them, 3 was a new norsesquiterpenoid, 8 was a new natural product, and 5, 6, 11, 20, 21 were isolated from A. oxyphylla for the first time. Twenty sesquiterpenoids, 1–5 and 7–21, were investigated for their in vitro acetylcholinesterase (AChE) inhibitory activities, including previously isolated seven sesquiterpenoids from A. oxyphylla, (11S)-12-chloronootkaton-11-ol (1), (11R)-12-chloronootkaton-11-ol (2), nootkatone (4), oxyphyllenodiol A (9), oxyphyllenodiol B (10), 7-epiteucrenone B (14), and alpinenone (19). TLC-Bioautographic assay indicated that 1–4, 7, 14, 16, 18, 19, and 21 displayed anti-AChE activities at 10 nmol. Microplate assay confirmed that 19, 18, 16, and 21 displayed moderate-to-weak anti-AChE activities at the concentration of 100 μM, and 19 was the most potent inhibitor with an IC50 value of 81.6±3.5 μM. The presence of anti-AChE sesquiterpenoids in A. oxyphylla may partially support the traditional use of this fruit for the treatment of dementia.

Two New Cytotoxic Spirostane-Steroidal Saponins from the Roots of Bletilla striata

Abstract: Two new spirostane-steroidal saponins, bletilnoside A (1) and bletilnoside B (2), together with five known compounds, 3–7, were isolated from the roots of Bletilla striata (Thunb.) Reichb. F. The structures of the new compounds were determined based on their 1D- and 2D-NMR spectral data. The isolated compounds 1–7 were tested for cytotoxicity against four human tumor cells (A549, SK-OV-3, SK-MEL-2, and HCT15) in vitro using a sulforhodamin B bioassay, and compounds 1, 2, and 5 showed significant cytotoxicities against all tested tumor cell lines with IC50 values ranging from 3.98±0.16 to 12.10±0.40 μM.

Palladium‐ and Solvent‐Free Synthesis of Ynones by Copper(I)‐Catalyzed Acylation of Terminal Alkynes with Acyl Chlorides under Aerobic Conditions

Abstract: Air-stable CuI/cryptand-22 complex was found to be a highly active catalyst for the solvent-free cross-coupling reaction of terminal alkynes with different acyl chlorides in the presence of Et3N as base to give the corresponding ynones in quantitative yields.

Organocatalyzed and Uncatalyzed CC/CC and CC/CN Exchange Processes between Knoevenagel and Imine Compounds in Dynamic Covalent Chemistry

Abstract: Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by CC and CN bonds through reversible double-bond formation, and cleavage in CC/CC and CC/CN exchange processes. The reversibility of the Knoevenagel reaction has been explored, and CC/CC C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as L-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible CC/CC exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (CC/CN exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on CC/CC and CC/CN exchange systems.

Synthesis of Novel α-(Acyloxy)-α-(quinolin-4-yl)acetamides by a Three-Component Reaction between an Isocyanide, Quinoline-4-carbaldehyde, and Arenecarboxylic Acids

Abstract: Novel α-(acyloxy)-α-(quinolin-4-yl)acetamides were synthesized by the Passerini three-component reaction between an isocyanide, quinoline-4-carbaldehyde, and arenecarboxylic acids in H2O. The reactions were carried out in one pot at room temperature with quantitative yields.

An Approach to the Synthesis of 7-Amino-6-imino-9-phenyl-6H-benzo[c]chromene-8-carbonitrile Derivatives via a Three-Component Reaction under Ultrasonic Irradiation

Abstract: An efficient synthesis of 7-amino-6-imino-9-phenyl-6H-benzo[c]chromene-8-carbonitrile derivatives 3 by a three-component reaction of salicylaldehydes (=2-hydroxybenzaldehydes) 1, malononitrile (=propanedinitrile), and 2-(1-arylethylidene)malononitrile 2 under ultrasonic irradiation in EtOH is reported. Good yields, short reaction times, and easy purification are the main advantages of the present method. The structures were confirmed spectroscopically (IR, 1H- and 13C-NMR, and EI-MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).

Confusing Quantitative Descriptions of Bronsted-Lowry Acid-Base Equilibria in Chemistry Textbooks: A Critical Review and Clarifications for Chemical Educators

Abstract: In chemistry textbooks, the pKa,H2O value of water in the solvent water at 25 degrees C is sometimes given as 14.0, sometimes as 15.7. This is confusing. The particular chemical reaction considered is the one in which water as BrOnstedLowry acid reacts with water as BrOnstedLowry base in water as solvent to yield equal concentrations of hydrated oxonium and hydroxide ions, H3O+(aq) and HO-(aq), respectively. This reaction is also known as the self-ionization' of water for which the equilibrium constant is abbreviated as K-w with its known value of 10(-14.0) at 25 degrees C, i.e., pK(w)(25 degrees C)=14.0. Identical values for pKa,H2O and pK(w) at a fixed temperature appear reasonable, since Ka,H2O and K-w refer to one and the same reaction. Therefore, reasons for the apparent disagreement between the thermodynamically correct' pK(a) value for water (14.0 at 25 degrees C) and the value reported in most organic chemistry textbooks (15.7) should be discussed when teaching acidbase chemistry. There are good arguments for introducing, from the very beginning, the concepts of activity and thermodynamic standard states when teaching quantitative aspects of chemical equilibria. This also explains in a straightforward way why all thermodynamic equilibrium constants, including K-w, are dimensionless, and why pKH3O+(25 degrees C)=0.

Rare C25 Steroids Produced by Penicillium chrysogenum P1X, a Fungal Endophyte of Huperzia serrata

Abstract: Three new metabolites, norcyclocitrinol A (1), erythro-11α-hydroxyneocyclocitrinol (2), and pesudocyclocitrinol A (3), along with six known analogs, i.e., neocyclocitrinols A–D (4–7, resp.), cyclocitrinol (8), and 24-epicyclocitrinol (9), were isolated and identified from the culture broth of Penicillium chrysogenum P1X, a fungal endophyte of Huperzia serrata. Compounds 1–9 were identified by spectroscopic methods to share the same C25-steroid skeleton featuring an unusual bicyclo[4.4.1] A/B ring system. In particular, 1 represents the first example of a C25 steroid with a bisnor C-atom side chain. All compounds were evaluated for their cytotoxic activities against HeLa and HepG2 cell lines. However, none of them exhibited a significant cytotoxicity at a concentration of 20 μM.

Epunctanone, a New Benzophenone, and Further Secondary Metabolites from Garcinia epunctata Stapf (Guttiferae)

Abstract: A new polyprenylated benzophenone, named epunctanone (1), was isolated from the stem bark of Garcinia epunctata Stapf, together with eight known compounds, 7-epiisogarcinol (2), 2,6-dimethoxy-p-benzoquinone (3), friedelin (4), lupeol (5), 16β-hydroxylupeol (6), betulin (7), stigmasterol (8), and rheediaxanthone A (9). The structure of epunctanone (1) was established by detailed analysis of its spectroscopic data, especially 1D- and 2D-NMR, and HR-MS data. All these compounds were evaluated for their antimicrobial and anti-protozoan activities. They were also assayed to determine if any of the compounds were nonpeptide agonist ligands for nematodal G-protein-coupled receptors, which would be an indication of potential antinematodal activity. Among the isolated compounds, 7-epiisogarcinol (2) was the most active against Candida albicans.

Cytotoxic Amides and Quinolones from Clausena lansium

Abstract: Two new amides, claulansamides A and B (1 and 2, resp.), together with five known amides, 3-7 and six known quinolones, 8-13, were isolated from the stems and roots of Clausena lansium. Their structures were elucidated on the basis of extensive spectroscopic methods. Their absolute configurations were determined by single-crystal X-ray diffraction technique, CD, and optical rotation. HPLC Chiral separation of 1 afforded two enantiomers, (+)- and (-)-claulansamide A, respectively. Compounds 9, 12, and 13 were isolated from the genus Clausena for the first time. All compounds were evaluated for their cytotoxic activities against A549, BGC-823, and HeLa cancer cell lines. However, only 9 showed cytotoxic activity against A549 cell line with an IC50 value of 46.3 mu M, and 11 against BGC-823 and HeLa cell lines with the IC50 values of 55.0 and 14.7 mu M, respectively.

Regularity of Intermittent Bursts in BriggsRauscher Oscillating Systems with Phenol

Abstract: The intermittency or intermittent bursting as the type of dynamic state when two qualitatively different behaviors replace one another randomly during the course of the reaction, although all the control parameters remain constant, is found in the BriggsRauscher oscillating system moderated by a very small amount of phenol. Within a range of phenol concentrations, the oscillation amplitude is diminished considerably, and after oscillations cease, they repeat intermittently, giving several bursts of oscillations. For the concentrations used here, the range of phenol concentrations where intermittent bursting oscillations occur in a closed reactor is ca. 1.8 � 10 � 5 to 3.6 � 10 � 5 m. Bursting also occurs in an open reactor and can be sustained indefinitely at 5.53 � 10 � 5 m concentration. The intermittent bursting behavior is robust, and can be achieved at a variety of conditions.

Palmarumycins from the Endophytic Fungus Lasiodiplodia pseudotheobromae XSZ‐3

Abstract: One new and three known spiro-dioxynaphthalene compounds, related to palmarumycins, were isolated from the extracts of fungus Lasiodiplodia pseudotheobromae XSZ-3. Their structures were established by spectroscopic methods (1D- and 2D-NMR, HR-ESI-MS, etc.). The absolute configuration of 1 was determined by comparison of quantum-chemical TDDFT (time-dependent density-functional theory) calculated and experimental ECD (electronic circular dichroism) spectra. The cytotoxic activities of 1–4 against HL-60 cell line were evaluated by trypan blue-staining assay.

Flavonol Glycosides with α-Glucosidase Inhibitory Activities and New Flavone C-Diosides from the Leaves of Machilus konishii

Abstract: Seventeen flavonoids, five of which are flavone C-diosides, 1–5, were isolated from the BuOH- and AcOEt-soluble fractions of the leaf extract of Machilus konishii. Among 1–5, apigenin 6-C-β-D-xylopyranosyl-2″-O-β-D-glucopyranoside (2), apigenin 8-C-α-L-arabinopyranosyl-2″-O-β-D-glucopyranoside (4), and apigenin 8-C-β-D-xylopyranosyl-2″-O-β-D-glucopyranoside (5) are new. Both 4 and 5 are present as rotamer pairs. The structures of the new compounds were elucidated on the basis of NMR-spectroscopic analyses and MS data. In addition, the 1H- and 13C-NMR data of apigenin 6-C-α-L-arabinopyranosyl-2″-O-β-D-glucopyranoside (3) were assigned for the first time. The isolated compounds were assayed against α-glucosidase (type IV from Bacillus stearothermophilus). Kaempferol 3-O-(2-β-D-apiofuranosyl)-α-L-rhamnopyranoside (12) was found to possess the best inhibitory activity with an IC50 value of 29.3 μM.

Highly Convergent One-Pot Four-Component Regioselective Synthesis of Spiro-pyranopyrazoles and Oxa-aza-[3.3.3]propellanes

Abstract: A concise and efficient route for the synthesis of spiro-pyranopyrazoles and oxa-aza-[3.3.3]propellanes by simple regioselective multicomponent reaction of ninhydrin, malononitrile, hydrazine derivatives, and β-keto esters or dimethyl acetylenedicarboxylate was developed. This protocol provides an alternative method for combinatorial and parallel syntheses in drug discovery. The value of this method lies in its simplicity, regioselectivity, and good yields. The structures of 3 and 4 were corroborated spectroscopically (IR, 1H- and 13C-NMR, and EI-MS). A plausible mechanism for this type of reaction is proposed (Schemes 2 and 3).

One-Pot Synthesis of Novel Pyrrolo[1,2-a]quinoxaline-4(5H)-ones Using Benzene-1,2-diamine, Acetylenedicarboxylates, and β-Nitrostyrene Derivatives

Abstract: The reaction between a variety of o-phenylenediamines (=benzene-1,2-diamines), dialkyl acetylenedicarboxylates, and derivatives of nitrostyrene (=(E)-(2-nitroethenyl)benzene) in the presence of sulfamic acid (SA; H3NSO3) as catalyst led to the corresponding pyrrolo[1,2-a]quinoxaline-4(5H)-one derivatives in high yields.

A Novel Synthesis of Quinazolines by Cyclization of 1‐(2‐Isocyanophenyl)alkylideneamines Generated by the Treatment of 2‐(1‐Azidoalkyl)phenyl Isocyanides with NaH

Abstract: A new and efficient method for the synthesis of quinazolines has been developed. Thus, N-[2-(1-azidoalkyl)phenyl]formamides 1 are dehydrated with POCl3 to give the corresponding 2-(1-azidoalkyl)phenyl isocyanides 2, which are then treated with NaH in DMF at 0° to give quinazolines 6 in satisfactory yields via cyclization of 1-(2-isocyanophenyl)alkylideneamine intermediates 4. This methodology can be applied to the synthesis of the 7-azaanalogs of quinazolines, i.e., pyrido[3,4-d]pyrimidines 9.

Two New Sesquiterpenoids from the Rhizomes of Curcuma xanthorrhiza

Abstract: Zedoardiol (1), a new furanoguaiane sesquiterpenoid, and 3,4-dihydroxybisabola-1,10-diene (2), a new naturally occurring bisabolane sesquiterpenoid, together with six known compounds, were isolated from Curcuma xanthorrhiza Roxb. Their structures were determined on the basis of comprehensive spectroscopic analyses, mainly 1D- and 2D-NMR, MS, IR and X-ray single-crystal diffraction. Herein, the isolation and structure elucidation of the compounds are described.

New Cytotoxic Laurene-, Cuparene-, and Laurokamurene-Type Sesquiterpenes from the Red Alga Laurencia obtusa

Abstract: Three new sesquiterpene alcohols, laur-2-ene-3,12-diol (1), cuparene-3,12-diol (2), and 8,11- dihydro-1-methoxylaurokamuren-12-ol (3), along with one known diterpene, kahukuen-10-ol (4) have been isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, i.e., KB, HepG2, and MCF-7. Compound 4 exhibited a wide range of cytotoxic activity against KB, HepG2, and MCF-7 cell lines with IC50 of 0.100, 0.057, and 0.054 mm, respectively. In addition, 1 showed moderate activities towards KB and MCF-7 cell lines with IC50 values of 0.171 and 0.184 mm, respectively and 2 exhibited a moderate activity against KB cell line at a concentration of 0.213 mg/ml. On the other hand, compound 3 exhibited no cytotoxic activity against any of the three cell lines.

Characterization of Eight New Secondary Metabolites from the Mutant Strain G-444 of Tubercularia sp TF5

Abstract: 973 Programs [2010CB833802, 2012CB721005]; National Science Fund for Distinguished Young Scholars [30325044]

Labdane Diterpenoids from the Roots of Amomum maximum and Their Cytotoxic Evaluation

Abstract: by Jian-Guang Luo, Hong Yin, Bo-Yi Fan, and Ling-Yi Kong*State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry,China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, P. R. China(phone/fax: þ86-25-83271405; e-mail: cpu_lykong@126.com)A rare labdane diterpene g-lactam, 1, and two new labdane diterpenoids, 2 and 3, along with twoknown diterpenes, 4 and 5, were isolated from the roots of Amomum maximum. Their structures wereestablished on the basis of spectroscopic data. All of the isolates were evaluated for their cytotoxicactivities, and compound 3 was found to exhibit an inhibitory activity against MG-63 cell lines with anIC

Lycopodium Alkaloids from Huperzia serrata

Abstract: Three new lycopodium alkaloids, huperserramines A–C (1–3, resp.), along with 15 known ones, lycopodine-6α,11α-diol (4), lycoposerramine H (5), lycoposerramine I (6), lycopodine-6α-ol (7), lycoposerramine M (8), diphaladine A (9), lycoposerramine K (10), lycoposerramine W (11), huperzine M (12), luciduline (13), phlegmariuine N (14), huperzine A (15), huperzine B (16), lycodine (17), and lycoposerramine R (18), were isolated from the whole plant of Huperzia serrata. Their structures were established by spectroscopic methods, including 2D-NMR and MS analyses. All the isolates were evaluated for their inhibitory effects on acetylcholinesterase (AChE) and α-glucosidase. As a result, lycopodine-6α,11α-diol (4) exhibited more potent α-glucosidase inhibitory activity (IC50 148±5.5 μM) than the positive control acarbose (IC50 376.3±2.7 μM).

Two New Iridoids from the Root and Rhizome of Valeriana jatamansi Jones

Abstract: Two new iridoids, jatamanvaltrates P and Q (1 and 2, resp.), together with three known iridoids, rupesin B (3), chlorovaltrate (4), and valtrate (5), were isolated from the root and rhizome of Valeriana jatamansi Jones. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D-NMR techniques.