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A palladium-catalyzed annulation reaction of 2-iodobiphenyls with 2-halogenoanilines has been developed. A variety of 2-iodobiphenyls and 2-halogenoanilines can undergo this transformation. Diversified tribenzo[b,d,f]azepine derivatives can be synthesized in moderate to excellent yields according to this method.

A copper-catalyzed three-component reaction of terminal alkynes, TsN3, and tertiary allylic amines is developed toward the one-pot synthesis of α-allylic amidines. The product was synthesized on gram scale under 1 mol % of catalyst loading. Transformations of products into alkenyl amine and other nitrogen-containing compounds are demonstrated without any loss of stereochemical information.

Carbon nitride (C3N4) is a promising photocatalyst that can be applied in environmental remediation and energy conversion. However, the absorption range and charge separation efficiency of C3N4 are still severely restricted for its large-scale practical applications. Herein, we demonstrate a simple thermal polymerization and electrodeposition method, followed by partial etching strategy to synthesize direct Z-scheme porous zinc oxide/amorphous carbon nitride/manganese dioxide hybrid core-shell nanorod array (denoted as P-ZnO/ACN/MnO2) by encapsulating amorphous carbon nitride layers (ACN) and manganese dioxide nanosheets (MnO2) on the zinc oxide nanorod arrays (denoted as ZnO). Interestingly, ZnO serves as the collector of charge carriers and MnO2 plays a significant role in protecting ACN from corrosion. The as-prepared Z-scheme P-ZnO/ACN/MnO2 heterojunction exhibits high photocurrent density of 5.2 mA cm−2 at 0.6 V vs. Ag/AgCl, high photoconversion efficiency 0.98%, and universal photoelectrocatalytic degradation activity for degradation of organic dyes under visible light irradiation. The band gap energy and conduction band position of ZnO, ACN and MnO2 are calculated by UV–visible diffuse reflection and Mott-Schottky measurement, which strongly support the direct Z-scheme charge carrier migration mechanism. This finding provides an efficient strategy to construct highly active and stable C3N4-based Z-scheme photocatalytic system.

A palladium-catalyzed annulation reaction of 2-iodobiphenyls with 2-halogenoanilines has been developed. A variety of 2-iodobiphenyls and 2-halogenoanilines can undergo this transformation. Diversified tribenzo[

A modular synthesis of 2,8-dioxabicyclo[3.2.1]octane (2,8-DOBCO) ketals is realized by sequential catalysis. The key intermediates, e-hydroxyl-β,γ-unsaturated ketones, are readily available by Ni-catalyzed three-component coupling of 1,3-dienes, aldehydes, and acylzirconocene reagents. These polyfunctionalized ketones can undergo a V-catalyzed cascade of epoxidation and ring rearrangement to provide access to 6-hydroxyl-2,8-DOBCOs. Mechanistic studies indicate that the V(V) species, generated under epoxidation conditions, promotes the ring rearrangement in a stereospecific manner. Meanwhile, the e-hydroxyl-β,γ-unsaturated ketones are transformed into 6-amino-2,8-DOBCOs by a Cu-catalyzed cascade of aziridination and ring rearrangement. In the end, the one-pot approach toward 6-hydroxyl- or 6-amino-2,8-DOBCOs from 1,3-diene, aldehydes, and acylzirconocene reagents is more favorable.

An organocatalyzed asymmetric sulfa-Michael addition of thiocarboxylic acids to β-trifluoromethyl-α,β-unsaturated ketones with a chiral bifunctional amine-squaramide as the catalyst is presented. A wide range of chiral ketone compounds bearing a sulfur atom and a trifluoromethyl group at the stereogenic carbon center could be obtained with excellent results (up to 99% yield, 97% ee) under mild conditions. The developed catalytic system is well-tolerated to both (E)-and (Z)-β-trifluoromethylated-α,β-unsaturated ketones.

We reported a practical non-destructive method for real-time detection of the ant alarm pheromone by silver ion-assisted ESI-MS. Polyrhachis vicina Roger workers were placed directly in the ESI source. The heated dry gas was used to make the ants feel threatened and release their alarm pheromone. When methanol was introduced to the ESI source, no peaks were detected. New peaks at m/z 221.0100, 223.0094, 239.0197, and 241.0195 were observed when a methanol solution of AgNO3 was used instead of pure methanol. Accurate masses, silver isotopes, and collision-induced dissociation experiments indicated that the four peaks corresponded to an unknown compound with the molecular formula C7H14O. The fragmentation and reactions of the functional groups of reference compounds suggested that the unknown pheromone is not an ether, aldehyde, or alcohol. The pheromone was identified as 4-methyl-2-hexanone by comparing the relative abundance of product ions with those of reference ketones.

A combined process of denitrification-partial nitritation-ANAMMOX based on a zeolite biological aerated filter (ZBAF) was applied to treat mature landfill leachate. We investigate the partial nitritation characteristics of the ZBAF and the nitrogen removal performance as well as the carbon removal performance of the combined process. Results showed that, based on the selective inhibition of nitrite oxidizing bacteria (NOB) by free ammonia (FA), the ZBAF could successfully achieve stable and efficient partial nitrification of mature landfill leachate, with an average nitrite accumulation rate (NAR) of 93.8% and a maximum nitrite production rate (NPR) of 1.659 kg·(m

A novel small-sized discotic core was constructed by fusing an imide unit with well-known triphenylene core. All target compounds 6a-k self assemble into a liquid crystalline phases having high clearing temperatures and broad phase ranges over 200 °C, and exhibit green luminescence both in solution and solid states. On cooling from the isotropic phase, compounds 6d-e and 6i-j containing the branched N-alkyl chain show only one peak for the isotropic to mesophase transition which is stable down to −50 °C. Comparison of 6a's mesomorphic behaviors and photophysical properties to a known hexahexyloxytriphenylene (1a) and the parent compound (4a) demonstrates the importance of peripherally attached functional groups in stabilizing columnar mesophases and inducing long-wavelength emission. Both the experimental results and computational calculations show that suitable peripheral functionalization of the discotic liquid crystal molecules not only results in significant differences in mesogenic behavior of the molecules, but also renders the molecules with the interesting optoelectronic properties, including large Stokes shifts and low-lying LUMO energy levels.

Eight previously undescribed oleanane-type triterpenoid saponins, clematangoticosides A-H, together with eight known saponins, were isolated from the whole plants of Clematis tangutica (Maxim.) Korsh. Their structures were elucidated by extensive spectroscopic analysis, in combination with chemical methods (acid hydrolysis and mild alkaline hydrolysis). Clematangoticosides D-G were found to be unusual 23, 28-bidesmosidic glycosides. The cytotoxic activities of all of the isolated saponins were evaluated against the four human cancer cell lines SGC-7901, HepG2, HL-60 and U251MG. Clematoside S, sapindoside B, kalopanax saponin A, and koelreuteria saponin A exhibited cytotoxicity against all of the test cancer cell lines with IC50 values in the range of 1.88-27.20 μM, while clematangoticoside D and F showed selective cytotoxicity against SGC-7901 with IC50 values of 24.22 and 21.35 μM, respectively.

Designing direct Z-scheme photocatalytic systems with core-shell architecture is crucial for effective charge separation towards sustainable photocatalysis. Herein, the core-shell heterojunction photocatalyst consisting of α-Fe2O3 nanoparticle layers encapsulating CeO2 nanotube arrays (Ce@Fe) was successfully synthesized through a simple and feasible strategy. The Ce@Fe heterojunctions exhibit the enhanced solar light scattering and absorption performance from 380 nm to 490 nm. The formed direct Z-scheme band structure between CeO2 and α-Fe2O3 further promotes the efficiency of carrier separation and transfer, and the core-shell nanotube array structure provides high specific surface area for antibiotic adsorption and enhanced light scattering, significantly improving the photoelectrocatalytic activity. Impressively, the unique photoelectrode achieves the highest pollutant removal efficiency of 88.6% for photoelectrocatalytic tetracycline degradation at 1 h under full light irradiation, and affords superior stability and strong alkaline resistance, which is expected to photoelectrocatalytic degrade antibiotics with high efficiency and environmental protection in harsh environment. Furthermore, the novel photoelectrocatalytic mechanism involving transfer behaviors of charge carriers, generation of reactive species, degradation intermediate products of tetracycline can be adopted after growing α-Fe2O3 layers onto CeO2 nanotube arrays, in accordance with direct Z-scheme mechanism.

A para-selective CH amidation of simple arenes with nitriles has been developed. By increasing the amount of arenes, a further meta-selective CH arylation of the produced amides occurred. Both steric and electronic effects are utilized to control the selectivity, resulting in only para-selective amidation products. The readily available nitriles as amidation reagents instead of amides makes the synthesis of N-arylamides more accessible.

A method for the enantioselective construction of hydrocarbazole skeletons through dearomative [4 + 2] annulation of 3-nitroindoles with Nazarov reagents is reported. The reactions use multiple hydrogen-bonding bifunctional thiourea as catalyst and are highly diastereo- and enantioselective (up to >20:1 dr and >99% ee). The protocol was demonstrated by preparative-scale experiment and the versatile conversion of the products. The multiple hydrogen-bonding in the catalyst plays a pivotal role in the reactivity and stereoselectivity.

Hexasubstituted triphenylene (1a) containing four alkoxy and two adjacent methoxycarbonyl tails can be smoothly brominated or nitrated at its α-position(s) of two electron-rich rings to give a series of bromides and nitro compounds through electrophilic aromatic substitutions. Positions of bromo or nitro groups in target compounds were unambiguously established by combined analysis of 2D nuclear magnetic resonance experiments including nuclear Overhauser effect and heteronuclear multiple-bond correlation which indicated that monobromination or mononitration occurred preferentially at position 8 or 5 of 1a, respectively. Calculations of molecular geometry on 2a–e reveal that the α-Br or α-NO2 group(s) would induce different degrees of helical deformation in the triphenylene core and the degree of non-planarity decrease in the following order: 2c > 2b > 2e > 2a > 2d. In contrast to highly twisted 2b–c and 2e, which did not form a mesophase, the formation of a hexagonal columnar phase at room temperature even down to −50°C was observed and confirmed by polarising optical microscopy and X-ray diffraction for sterically less hindered, monosubstituted 2a and 2d.

A comparative study of our established synthetic approaches to hexasubsituted triphenylenes 2,3-dicarboxylic esters containing four identical β-alkoxy and two adjacent β-alkoxycarbonyl side chains shows that the phase behaviours of small-sized discotic liquid crystals can be tailored over a wide range by simply varying the length of the peripheral alkyl chains. All the prepared esters in two series were observed to form a single hexagonal columnar phase, except for Tp4-1 having four β-butyloxy and two adjacent β-methoxycarbonyl chains which displays two columnar mesophase behaviours with a transition from the columnar plastic phase to hexagonal columnar phase. A significant difference between the two mesophase was observed in the variable temperature X-ray diffraction studies, and the mesophase assignment was also confirmed by polarising optical microscopy and differential scanning calorimetry. Moreover, the prepared esters in each series display the general trend of decreasing clearing temperature upon increasing alkoxy or alkoxycarbonyl chains length. The intermediate triphenylene 2,3-dicarboxylic acids were also found not only to exhibit columnar hexagonal mesophase over a narrower temperature range by maintaining high melting and clearing points but also to form organogel on mixing with toluene or dichloromethane with the assistance of hydrogen bonding.

Because of fuzziness, uncertainty of structure and researchers practical experience, it is more practical to express the relative importance of indexes with interval number. Firstly, according to researchers indeterminate judgment matrix, the upper and lower bound matrixes are formed; secondly, the similarity and the differences of the upper and lower bound matrixes of the relative importance matrix from different experts is studied by using the similarity theory of vector; lastly, certainty factor of researchers according to the upper and lower bound matrixes can be calculated, and the average value is regarded as the researchers certainty factor. The certainty factors of researchers upper and lower bound matrixes are consider together, the researchers experience is fully considered and the error from indeterminate judgment matrix to indeterminate judgment matrix is avoided. The result affords basis to calculate the weight coefficient, the research result comparing with the other method showed that the computation accuracy in this paper was very high.

Three new biphenyls, 4,7,8-trimethoxy-2,3-methylenedioxydibenzofuran (1), 7-hydroxy-4,8dimethoxy-2,3-methylenedioxydibenzofuran (2), and 3',5-dimethoxy-3,4-methylenedioxybiphenyl (3), along with eighteen known compounds (4-21) were isolated from the aerial part of Ribes takare D. Don. Their structures were elucidated on the basis of spectroscopic data. Compound 1 and compound 2 showed mild alpha-glucosidase inhibitory activity. (C) 2013 Guo-You Li and Dong-Mei Fang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

The relative isotopic abundance (RIA) measurement errors of a quadrupole time-of-flight (Q-ToF) instrument incorporating analog-to-digital converter detectors were systemically evaluated by stochastically collecting about 200 data in positive ion mass spectrometry (MS) mode. Errors varied with peak intensities at definite spectral acquisition rates but were very close, even if peak intensities changed sharply at different spectral acquisition rates with the same concentration. Intensity thresholds were systematically defined at 1 Hz of spectral acquisition rates. RIA measurement errors were also evaluated using peak area. It seemed that peak area was better adapted for the high-intensity ions while peak intensity was suited for very low-intensity ions. Several known compounds were selected for RIA measurements for product ions in tandem mass spectropmetry (MS/MS) mode. An extract of a representative traditional Chinese medicinal, Paederia scandens was analyzed with high-performance liquid chromatography-electrospray ionization-QToF-MS/MS. The unique elemental compositions of some compounds could not be identified even with exact masses and MS/MS spectra of measured and reference compounds. RIA errors, especially of (M + 2)M−1, provided vital information for determining the elemental composition.

An inexpensive BF3·Et2O-catalyzed annulation reaction of arylacetaldehydes with arylalkynes has been developed. Various substituted phenylacetaldehydes and phenylacetylenes can undergo this reaction, producing corresponding α-aryl substituted naphthalene derivatives. Use of inexpensive and readily available BF3·Et2O catalyst constitutes the most attractive advantage of this transformation.

Rhopeptin A was isolated as the first cyclopentapeptide from the moss Rhodobyum giganteum [Schwaegr.] Par. This novel compound consists of proline, phenylalanine, and 3-hydroxyproline ring-bonded amino acid residues connected to a tyrosine fragment via an ether bridge. Attached to a 3-hydroxyproline unit is a side chain of pyroglutamic acid residue. The structure of the peptide was deduced from the 1D- and 2D-NMR and MS data.

A para-selective CH amidation of simple arenes with nitriles has been developed. By increasing the amount of arenes, a further meta-selective CH arylation of the produced amides occurred. Both steric and electronic effects are utilized to control the selectivity, resulting in only para-selective amidation products. The readily available nitriles as amidation reagents instead of amides makes the synthesis of N-arylamides more accessible.

AIM: To study the chemical constituents in the bark of Styrax perkinsiae. METHODS: The compounds were isolated with chromatographic methods, and their chemical structures were elucidated on the basis of spectral data. RESULTS: Ten compounds were isolated and identified as 5-(2-propen-1-one)-7-methoxy-2-(3, 4-methylenedioxyphenyl) benzofuran (1), 1''-hydryoxyegonol gentiobioside (2), obassioside B (3), egonol (4), egonol glucoside (5), egonol gentiobioside (6), egonol gentiotrioside (7), styrax-lignolide B (8), styraxjaponoside C (9), and masutakeside I (10). CONCLUSION: Compounds 1 and 2 are new 2-phenylbenzofurans.

RATIONALE: Limonoids, a class of tetranortriterpenoids, exhibit various biological effects, such as insect antifeedant and growth regulating activities, antimicrobial activity, potent cell adhesion inhibitory effects, antimalarial activity, anticancer activities, and antioxidant activity. The potential application brings the need for reliable, fast and low-cost analysis of this class of compounds. METHODS: Six cipadesin limonoids (1-6), including a pairs of isomers, from leaves and barks of Cipadessa cinerascens were investigated by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in positive-ion mode. Characteristic processes were further studied by theoretical calculations. RESULTS: 1,3-Hydrogen rearrangement might play a significant role in the cleavage of -O-bridge bond in ring B and further produces some characteristic ions. For [M + Na](+) precursor ions, the product ion at m/z 133 might indicate the structure of ring A and the losses of CO2 and AcOH occur readily. Interestingly, the radical product ion at m/z 460 from [M + Na]+ ions seems to be the characteristic ion for compound 1. A deuterium-labeling experiment supported the processes forming the radical ion. For [M + NH4](+) ions, high-abundance product ions resulting from sequential loss of AcOH can be observed. In addition, a pairs of isomers was unambiguously differentiated based on MS or MS/MS spectra. CONCLUSIONS: In summary, sufficient information obtained from fragmentation experiments of [M + Na](+), [M + NH4](+) or [M + H](+) precursor ions is especially valuable for rapid identification of these limonoids or their metabolites in complex mixtures. The high-abundance radical product ion is of scientific interest. Copyright (C) 2012 John Wiley & Sons, Ltd.

The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid-phase microextraction (HS-SPME) and headspace liquid-phase microextraction (HS-LPME) combined with gas chromatography-mass spectrometry (GC-MS). The main volatiles from Mosla chinensis Maxim were studied in this paper. It can be seen that 61 compounds were separated and identified. Forty-nine volatile compounds were identified by SPME method, mainly including myrcene, α-terpinene, p-cymene, (E)-ocimene, thymol, thymol acetate and (E)-β-farnesene. Forty-five major volatile compounds were identified by LPME method, including α-thujene, α-pinene, camphene, butanoic acid, 2-methylpropyl ester, myrcene, butanoic acid, butyl ester, α-terpinene, p-cymene, (E)-ocimene, butane, 1,1-dibutoxy-, thymol, thymol acetate and (E)-β-farnesene. After analyzing the volatile compounds, multiple linear regression (MLR) method was used for building the regression model. Then the quantitative structure-retention relationship (QSRR) model was validated by predictive-ability test. The prediction results were in good agreement with the experimental values. The results demonstrated that headspace SPME-GC-MS and LPME-GC-MS are the simple, rapid and easy sample enrichment technique suitable for analysis of volatile compounds. This investigation provided an effective method for predicting the retention indices of new compounds even in the absence of the standard candidates.

The rule of full stress is the most direct and effective method of the optimal design for shape steel truss. The full stress optimal design study of shape steel truss is about the optimal design of the discrete variable, which is more difficult than that of the continuous variable. Through the section parameters in the table of the shape steel, the function of the section area and the inertial radius is created, the optimal design of the discrete variable is changed into the optimal design of the continuous variable and the computed efficiency of iteration is promoted. Lastly, the general program is studied. Through this program, the truss with different kind and different shape in various load case is designed automatically. The result shows that the computation efficiency and accuracy is increased greatly, the proposed method can be used in the optimal design of the large-scale truss and spatial truss widely.

Three new eudesmanolactones (=eudesmanolides), loloanolide A (1), loloanolide B (2), and 1-O-acetylloloanolide B (3), together with five known compounds, were isolated from the CHCl(3) extract of the aerial parts of Camchaya loloana. Their structures were elucidated on the basis of spectroscopic analysis. This type of eudesmanolactones bearing a 2-(hydroxymethyl) acryloyloxy group at C(8) was discovered for the first time. Compounds 1-3 exhibited cytotoxicity against the HepG2 cell line, with GI(50) values of 22.9, 18.1, and 12.8 nmol/ml, respectively.

Four new alkaloids, brevianamides O - R (1-4, resp.), were isolated from the AcOEt extract of the solid-state fermented rice culture of the fungus Aspergillus versicolor. Their structures were elucidated on the basis of spectroscopic analyses.

The mechanical model of the FRP Strengthened RC beam is studied in this paper. According to the static equivalence principle, the equivalence elastic modulus of the FRP strengthened RC beam simplified model is obtained; by using modal equivalence principle, the equivalence density of the model is also obtained. The result of virtual FRP strengthened RC beam shows that the method in this paper can be used widely with high accuracy.

Introduction - Biosynthesis of terretonin was studied due to the interesting skeleton of this series of sesterterpenoids. Very recently, Lopez-Gresa reported two new sesterterpenoids (terretonins E and F) which are inhibitors of the mammalian mitochondrial respiratory chain. Mass spectrometry (MS), especially tandem mass spectrometry, has been one of the most important physicochemical methods for the identification of trace natural products due to it rapidity, sensitivity and low levels of sample consumption. The potential application prospect and unique skeleton prompted us to study structural characterisation using MS. Objective - To obtain sufficient information for rapid structural elucidation of this class of compounds using MS. Methodology - The elemental composition of the product ions was confirmed by low-energy ESI-CID-QTOF-MS/MS analyses. The fragmentation pathways were postulated on the basis of ESI-QTOF-MS/MS/MS and ESI-IT-MSn spectra. Common features and major differences between ESI-QTOF-MS/MS and IT-MSn spectra were compared. For ESI-QTOF-MS/MS/MS experiments, capillary exit voltage was raised to induce in-source dissociation. Ammonium acetate or acetic acid were added into solutions to improve the intensity of [M + H](+). The collision energy was optimised to achieve sufficient fragmentation. Some fragmentation pathways were unambiguously proposed by the variety of abundance of fragment ions at different collision energies even without MSn spectra. Results - Fragmentation pathways of five representative sesterterpenoids were elucidated using ESI-QTOF-MS/MS/MS and ESI-IT-MSn in both positive- and negative-ion mode. The key group of characterising fragmentation profiles was ring B, and these fragmentation patterns are helpful to identify different types of sestertepenoids. Conclusion - Complementary information obtained from fragmentation experiments of [M + F](+) (or [M + NH4](+)) and [M - H](-) precursor ions is especially valuable for rapid identification of this kind of sesterterpenoid. Copyright (c) 2010 John Wiley & Sons, Ltd.

Diastereoisomeric linear and cyclic 'N-chiral quaternary ammonium salts' (QASs) were efficiently synthesized from corresponding L-amino acids in high yields. The diastereoisomers of each pair of 'N-chiral QASs' were successfully separated. The absolute configurations of these QASs were determined predominately by X-ray single-crystal analysis. The H-1-NMR data of 'N-chiral QASs' provided characteristic information on the configuration of the N-chiral center. 'N-Chiral QASs' exemplified by [N(R)]-2a and [N(S)]-2a are stable in protic and aprotic solvents within a broad pH and temperature range.

Two new iridoids, methyl (+)-rel-(1R,3S,4R,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H -1a,2-dioxacyclopent[cd]indene-4-carboxylate (1) and methyl (+)-rel-(1R,3S,4S,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H -1a,2-dioxacyclopent[cd]indene-4-carboxylate (2), were isolated from Viburnum cylindricum along with 14 known compounds. Their structures were determined by spectroscopic analyses. This type of iridoids bearing a MeO group at C(3) was discovered for the first time.

Two diastereoisomeric decalins, (2S,4aS,5S,6R)- and (2S,4aS,5R,6R)-5-(2-hydroxyethyl)-1,1,4a,6- tetramethyldecalin-2,6-diol (5 and 6) were prepared from the degradation products of oleanolic acid. Starting from 6, ( )-ambrox (4) was synthesized.

Five series of 37 new acylate and epoxide derivatives (3–39) of Euphorbia factor L3, a lathyrol diterpene isolated from Euphorbia lathyris, were designed by modifying the hydroxyl moiety of C-3, C-5, or C-15. Chemoreversal effects of the acylates on multidrug resistance (MDR) were evaluated in breast cancer multidrug-resistant MCF-7/ADR cells that overexpress P-glycoprotein (P-gp). Eight derivatives exhibited greater chemoreversal ability than verapamil (VRP) against adriamycin (ADR) resistance. Compounds 19 and 25 exhibited 4.8 and 4.0 times, respectively, more effective reversal ability than VRP against ADR resistance. To determine the key characteristics of Euphorbia factor L3 derivatives that contribute to MDR reversal, we conducted a structure–activity relationship study of these compounds. The simulation studies indicated different possible mechanisms and revealed the important influence of hydrophobic interactions and hydrogen bonds in the flexible cavity of P-gp.

A new secondary metabolite, 2-O-methylalternariol 4-O-β-[4-methoxyl-glucopyranoside] (1), together with four known compounds alternariol methyl ether (2), altenuene (3), isoaltenuene (4) and 2-(2′S-hydroxypropyl)-5-methyl-7-hydroxychromone (5), was isolated from the fungus Alternaria alternate cib-137. Its structure was elucidated on the basis of spectroscopic data. Compounds 3 and 4 demonstrated moderate activity against Staphylococcus aureus.

A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used to locate damage in the structure, and an iterative estimation scheme for solving nonlinear optimization programming problems based on the quadratic programming technique is used to identify the damage magnitude. A numerical example of a cantilever beam with single or multiple damages is used to examine the capability of the proposed grey-theory-based method to localize and identify damages. The factors of meas- urement noise and incomplete test data are also discussed. The numerical results showed that the damage in the structure can be localized correctly through using the grey-related coefficient of displacement curvature, and the damage magnitude can be iden- tified with a high degree of accuracy, regardless of the number of measured displacement nodes. This proposed method only requires limited static test data, which is easily available in practice, and has wide applications in structural damage detection.

5-Acylindoles were synthesized by regioselective acylation of 3-trifluoroacetylindole with acyl chloride under the catalysis of Lewis acids, followed by hydrolysis of trifluoroacetyl and decarboxylation. Polar solvents were beneficial to the acylation and most of the Lewis acids tested showed good catalytic activities.

A new bergenin derivative, 11-O-(3′-O-methylgalloyl)-bergenin, was isolated from the whole plants of Corylopsis willmottiae Rehd. et Wils, along with 11-O-galloylbergenin, 11-O-syringylbergenin, bergenin, 4-O-galloylbergenin, and 4,11-di-O-galloylbergenin. They were identified on the basis of spectral evidence.

Three new biphenyls, 4,7,8-trimethoxy-2,3-methylenedioxydibenzofuran (1), 7-hydroxy-4,8dimethoxy-2,3-methylenedioxydibenzofuran (2), and 3',5-dimethoxy-3,4-methylenedioxybiphenyl (3), along with eighteen known compounds (4-21) were isolated from the aerial part of Ribes takare D. Don. Their structures were elucidated on the basis of spectroscopic data. Compound 1 and compound 2 showed mild alpha-glucosidase inhibitory activity. (C) 2013 Guo-You Li and Dong-Mei Fang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Tobacco samples of a same cultivar grown in different plantations in China were evaluated for their chemical compositions at different maturities for the first time. This was accomplished by a comprehensive and reliable method using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (HPLC-PDA-QTOF-MS) to analyze the fat-soluble and polar components in 12 batches of tobacco samples of three origins and four maturities. The GC MS analyses showed that tobacco samples harvested at 40 days after transplantation exhibited more fat-soluble components, while those harvested at 100 days after transplantation exhibited the least fat-soluble components. Tentatively, identification of the main components as well as quantitative analyses of eight reference compounds, including five alkaloids, two polyphenols, and a coumarin, was performed by the developed HPLC-QTOF-PDA method. Results showed significant differences among origins and maturities in the contents of these compounds. The nicotine contents showed great variety among the 12 tobacco samples. The highest nicotine content were found in a sample from Zhengzhou harvested at 40 days after transplantation (ZZ-T with 25399.39 +/- 308.95 mu g/g), and the lowest nicotine level was detected in a sample from Zunyi harvested at 60 days after transplantation (ZY-X with 1654.49 +/- 34.52 mu g/g). The highest level of rutin was found in a Jiangchuan sample harvested at 60 days after transplantation (JC-X with 725.93 +/- 40.70 mu g/g), and the lowest rutin content was detected in a Zunyi tobacco sample harvested at 60 days after transplantation (ZY-X with 87.42 +/- 2.78 mu g/g). The developed method provided a convenient approach which might be applied for rapid maturity evaluation and tobacco flavor identification and also holds the potential for analysis of compounds present in other plants.