bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: One‐Step Synthesis of Tetrazolo[1,5‐a]pyrimidines by Cyclization Reaction of Dihydropyrimidine‐2‐thiones with Sodium Azide.
Authors: Wang Xi‐Cun , Wei Ying , Da Yu‐Xia , Zhang Zhang , Quan Zheng‐Jun 
Published: March 2012

AbstractCompared to established methods, the approach provides lower temperatures, higher yields, and shorter reaction times.
ChemInform Abstract: Stereoselective Synthesis of C‐Substituted Morpholine Derivatives Using Reductive Etherification Reaction: Total Synthesis of Chelonin C.
Authors: Gharpure Santosh J. , Prasad J. V. K. 
Published: March 2012

AbstractA new and stereoselective approach to polysubstituted morpholines and fused analogues is reported.
ChemInform Abstract: Dihydroazamacrosphelides: Synthesis and Apoptosis Inducing Activities.
Authors: Sugimoto Kenji , Kobayashi Yuta , Kondo Takashi , Toyooka Naoki , Nemoto Hideo , Matsuya Yuji 
Published: March 2012

AbstractCompounds (II) and (VII) induce apoptosis on lymphoma cells although the activity is rather moderate.
ChemInform Abstract: Facile Syntheses of Substituted, Conformationally Constrained Benzoxazocines and Benzazocines via Sequential Multicomponent Assembly and Cyclization.
Authors: Sahn James J. , Martin Stephen F. 
Published: March 2012

AbstractThe diol (I) is developed as central intermediate for the synthesis of bicyclic benzoxazocines and a variety of related compounds including O‐substituted derivatives and non‐bridged compounds.
ChemInform Abstract: Mild Generation of Selenolate Nucleophiles by Thiol Reduction of Diselenides: Convenient Syntheses of Selenyl‐Substituted Aryl Aldehydes.
Authors: Dubey Rashmi , Lee Hangeun , Nam Do‐Hyun , Lim Dongyeol 
Published: March 2012

AbstractIn the presence of base and dithiothreitol as reducing agent, selenyl‐substituted aromatic and heteroaromatic aldehydes are readily available from ortho‐halogenated precursors and diorganyl diselenides.
ChemInform Abstract: Unique Salt Effect on the High Yield Synthesis of Acid‐Labile Terpene Oxides Using Hydrogen Peroxide under Acidic Aqueous Conditions.
Authors: Hachiya Houjin , Kon Yoshihiro , Ono Yutaka , Takumi Kiyoshi , Sasagawa Naoki , Ezaki Yoichiro , Sato Kazuhiko 
Published: March 2012

AbstractThe use of sodium sulfate as an additive in the oxidation of various terpenes with hydrogen peroxide allows the synthesis of acid‐labile epoxides in high yields.
ChemInform Abstract: Diabetic Nephropathy‐Related Active Cyclic Peptides from the Roots of Brachystemma calycinum.
Authors: Cheng Yong‐Xian , Zhou Li‐Li , Yan Yong‐Ming , Chen Ke‐Xin , Hou Fan‐Fan 
Published: March 2012

AbstractThree new cyclic peptides, duanbanhuains A (I), B (II), and C (III), are isolated from the roots of Brachystemma calycinum used in traditional Chinese medicine to treat rheumatic diseases.
ChemInform Abstract: Enzymatic Synthesis of D‐Sorbose and D‐Psicose with Aldolase RhaD: Effect of Acceptor Configuration on Enzyme Stereoselectivity.
Authors: Li Zijie , Cai Li , Qi Qingsheng , Wang Peng George 
Published: March 2012

AbstractThe synthesis of the rare title sugars (III) and (IV) starts from D‐glyceraldehyde (I).
ChemInform Abstract: Novel Cytotoxic Chalcones from Litsea rubescens and Litsea pedunculata.
Authors: Li Liang , Zhao Xing‐Tang , Luo Yi‐Ping , Zhao Jing‐Feng , Yang Xiao‐Dong , Zhang Hong‐Bing 
Published: March 2012

AbstractLitseanone A (I) and B (II) are isolated together with 7 known flavanoids from the stem bark of the title plant.
Acetalization of Carbonyl Compounds as Pentaerythritol Diacetals and Diketals in the Presence of Cellulose Sulfuric Acid as an Efficient, Biodegradable and Reusable Catalyst
Authors: Shaterian Hamid Reza , Rigi Fatemeh 
Published: March 2012

AbstractThis paper reports a practical and green method for the acetalization of carbonyl compounds as pentaerythritol diacetals and diketals derivatives using cellulose sulfuric acid as a biodegradable and reusable solid acid catalyst under thermal solvent‐free conditions.
β‐Cyclodextrin Immobilized onto Dowex Resin: A Unique Microvessel and Heterogeneous Catalyst in Nucleophilic Substitution Reactions
Authors: Kiasat Ali Reza , Zarinderakht Nasrollah , Sayyahi Soheil 
Published: March 2012

AbstractThe catalytic activity of β‐cyclodextrin immobilized on Dowex resin as an efficient solid‐liquid phase transfer catalyst was developed for the synthesis of alkyl thiocyanates and phenacyl derivatives in water. The nucleophilic substitution reactions were performed under mild reaction condition and gave the products in excellent yields. Furthermore, the catalyst could be recycled by facile separation without any loss of activity.
Synthesis and Antioxidant Activities of Novel 4,4′‐Arylmethylene‐bis(1H‐pyrazole‐5‐ol)s from Lignin
Authors: Yang Xiaohui , Zhang Pinghu , Zhou Yonghong , Wang Junsong , Liu Hongjun 
Published: March 2012

AbstractA series of novel bispyrazoles joined by arylmethylene at C‐4 position were synthesized with aromatic aldehydes obtained from lignin and screened for their in vitro antioxidant activities by N,N‐diphenyl‐N′‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylenzothiazoline‐sulphonic acid) diammonium salt (ABTS+) radical scavenging assays. All of these compounds exhibited good DPPH and ABST+ radical scavenging activities as compared to the standard, Trolox, which suggested their potential as promising agents for curing tumors or other free radical‐related diseases.
Modified Activated Carbon as Solid Phase Extraction Adsorbent for the Preconcentration and Determination of Trace As(III) in Environmental Samples by Graphite Furnace Atomic Absorption Spectrometry
Authors: Tavakkoli Nahid , Habibollahi Saeed , Amini Tehrani Shahla 
Published: March 2012

AbstractA simple and selective method was developed for the preconcentration, separation, and determination of trace amounts of As(III) in an aqueous solution by solid phase extraction combined with graphite furnace atomic absorption spectrometry. Activated carbon (AC) was modified by sodium diethyldithiocarbamate (NaDDTC) and then used as a new, stable and easily prepared solid sorbent in a mini column for the extraction of As(III) in aqueous solution. Factors influencing the sorption and desorption of As(III), such as volume and concentration of eluent, sample pH, flow rate and effect of interfering ions on the recovery of As(III) have been systemically investigated. At pH 2.0 As(III) could be adsorbed quantitatively by NaDDTC‐AC, and then eluted completely with 2 mL of 3.0 mol·L−1 HNO3. The amount of eluted As(III) was measured using graphite furnace atomic absorption spectrometry. The detection limit of As(III) was 0.04 ng·mL−1 with enrichment factor of 100 and the relative standard deviation (RSD, n=8) was 1.58% at 10 ng·mL−1 level.
Density Functional Theoretical Study of Polynitrogen Compounds N5+Y− (Y=B(CF3)4, BF4, PF6 and B(N3)4)
Authors: Lian Peng , Lai Weipeng , Chang Haibo , Li Yanan , Li Hui , Yang Wei , Wang Youbing , Wang Bozhou , Xue Yongqiang 
Published: March 2012

AbstractThe structures and the stabilities of polynitrogen compounds N5+Y− [Y=B(CF3)4, BF4, PF6, and B(N3)4], as the potential high energy density compounds, have been investigated at the B3LYP/6‐31G(d,p) and B3LYP/6‐311+G(d,p) levels. On the basis of our geometry optimization calculations, the structural properties of the N5+Y− compounds are discussed, and it is found that the combination of the N5+ cation and the Y− anions leads to distortion of the structures of the Y− anions. Based on the TS calculations for the N2‐loss dissociations of the N5+Y− compounds, the stabilities of these compounds are discussed, and the following conclusion can be drawn that among the four compounds, N5+B(CF3)4− is the most stable one and N5+B(N3)4− is the most unstable, and the relative stability of these compounds is always consistent using different basis sets. From these discussions, it is revealed that there are close correlations between the stuctrual distortions of the Y? anions and the stabilities of the N5+Y− compounds, and between the nitrogen content in the compounds and the stabilities of the N5+Y− compounds.
Environmental Friendly Azide‐Alkyne Cycloaddition Reaction of Azides, Alkynes, and Organic Halides or Epoxides in Water: Efficient "Click" Synthesis of 1,2,3‐Triazole Derivatives by Cu Catalyst
Authors: Liu Jianming , Liu Muwen , Yue Yuanyuan , Yao Meihuan , Zhuo Kelei 
Published: March 2012

AbstractAn efficient click synthesis of 1,2,3‐triazole derivatives from benzyl halides or alkyl halides, epoxides, terminal alkynes, and sodium azides in the presence of copper salts and relative benzimidazole salts have been developed. This procedure eliminates the need to handle potentially organic azides, which are generated in situ. A broad spectrum of substrates can participate in the process effectively to produce the desired products in good yields.
Alum (KAl(SO4)2·12H2O) Catalyzed Multicomponent Transformation: Simple, Efficient, and Green Route to Synthesis of Functionalized Spiro[chromeno[2,3‐d]pyrimidine‐5,3′‐indoline]‐tetraones in Ionic Liquid Media
Authors: Mirhosseini Moghaddam Mojtaba , Bazgir Ayoob , Mohammad Mehdi Akhondi , Ghahremanzadeh Ramin 
Published: March 2012

AbstractThe combination of isatin, barbituric acid, and cyclohexane‐1,3‐dione derivatives in the presence of alum (KAl(SO4)2·12H2O) as a catalyst for 15 min was found to be a suitable and efficient method for the synthesis of spiro[chromeno[2,3‐d]pyrimidine‐5,3′‐indoline]‐tetraones.
Thermal Stability, Microstructure and Photocatalytic Activity of the Bismuth Oxybromide Photocatalyst
Authors: Yu Changlin , Zhou Wanqin , Yu Jimmyc , Cao Fangfang , Li Xin 
Published: March 2012

AbstractFlake BiOBr was first prepared by a solution method at room temperature. Then, the produced BiOBr was calcined at different temperatures. It was found that BiOBr is not a stable compound. It transforms to plate‐like Bi24O31Br11at around 750°C and the formed Bi24O31Br11 can further convert to rod‐like α‐Bi2O3 at around 850°C. The prepared compounds were characterized with X‐ray diffraction (XRD), N2 physical adsorption, scanning electron microscopy (SEM), and UV‐Vis diffuse reflectance spectra (DRS), respectively. The photocatalytic activity of the produced bismuth oxybromides was evaluated by photocatalytic decomposition of acid orange II under both visible light (λ>420 nm) and UV light (λ=365 nm) irradiation. Results show that these compounds have different band gaps and different photocatalytic properties. The band gap energies of the as‐prepared samples were found to be 2.82, 2.79, 2.60 and 3.15 eV for BiOBr, BiOBr/Bi24O31Br, Bi24O31Br, and α‐Bi2O3, respectively. Under both UV light and visible light irradiation, the photocatalytic activity follows the order: BiOBr/Bi24O31Br mixture>BiOBr>Bi24O31Br>α‐Bi2O3. The change in photocatalytic activity could be attributed to the different light absorption ability and microstructures of the photocatalysts.
Hydrogen Peroxide Sensor Based on Carbon Nanotubes/β‐Ni(OH)2 Nanocomposites
Authors: Zhang Xiaojun , Huang Yan , Gu Aixia , Wang Guangfeng , Fang Bin , Wu Huaqiang 
Published: March 2012

AbstractNi(OH)2 nanoflowers were synthesized by a simple and energy‐efficient wet chemistry method. The product was characterized by scanning electron microscopy (SEM) and X‐ray powder diffraction (XRD). Then Ni(OH)2 nanoflowers attached multi‐walled carbon nanotubes (MWCNTs) modified glassy carbon electrodes (GCE) were proposed (MWCNTs/Ni(OH)2/GCE) to use as electrochemical sensor to detect hydrogen peroxide. The results showed that the synergistic effect was obtained on the MWCNTs/Ni(OH)2/GCE whose sensitivity was better than that of Ni(OH)2/GCE. The linear range is from 0.2 to 22 mmol/L, the detection limit is 0.066 mmol/L, and the response time is <5 s. Satisfyingly, the MWCNTs/Ni(OH)2/GCE was not only successfully employed to eliminate the interferences from uric acid (UA), acid ascorbic (AA), dopamine (DA), glucose (GO) but also NO2− during the detection. The MWCNTs/Ni(OH)2/GCE allows highly sensitive, excellently selective and fast amperometric sensing of hydrogen peroxide and thus is promising for the future development of hydrogen peroxide sensors.
The chemical complexity of cellular microtubules: Tubulin post‐translational modification enzymes and their roles in tuning microtubule functions
Authors: Garnham Christopher P. , Roll‐Mecak Antonina 
Published: March 2012

AbstractCellular microtubules are marked by abundant and evolutionarily conserved post‐translational modifications that have the potential to tune their functions. This review focuses on the astonishing chemical complexity introduced in the tubulin heterodimer at the post‐translational level and summarizes the recent advances in identifying the enzymes responsible for these modifications and deciphering the consequences of tubulin's chemical diversity on the function of molecular motors and microtubule associated proteins. Published 2012 Wiley Periodicals, Inc.
Stabilization of actin filaments prevents germinal vesicle breakdown and affects microtubule organization in Xenopus oocytes
Authors: Okada Iyo , Fujiki Saburo , Iwase Shohei , Abe Hiroshi 
Published: March 2012

AbstractIn Xenopus oocytes, extremely giant nuclei, termed germinal vesicles, contain a large amount of actin filaments most likely for mechanical integrity. Here, we show that microinjection of phalloidin, an F‐actin‐stabilizing drug, prevents the germinal vesicle breakdown (GVBD) in oocytes treated with progesterone. These nuclei remained for more 12 h after control oocytes underwent GVBD. Immunostaining showed significant elevation of actin in the remaining nuclei and many actin filament bundles in the cytoplasm. Furthermore, microtubules formed unusual structures in both nuclei and cytoplasm of phalloidin‐injected oocytes stimulated by progesterone. Cytoplasmic microtubule arrays and intranuclear microtubules initially formed in phalloidin‐injected oocytes as control oocytes exhibited white maturation spots; these structures gradually disappeared and finally converged upon intranuclear short bundles when control oocytes completed maturation. In contrast, treatment of oocytes with jasplakinolide, a cell membrane‐permeable actin filament‐stabilizing drug, did not affect GVBD. This drug preferentially induced accumulation of actin filaments at the cortex without any increase in cytoplasmic actin staining. Based on these results, intranuclear and cytoplasmic actin filament dynamics appear to be required for the completion of GVBD and critically involved in the regulation of microtubule assembly during oocyte maturation in Xenopus laevis. © 2012 Wiley Periodicals, Inc
Synthesis, Chiral Resolution, and Absolute Configuration of Functionalized Tröger’s Base Derivatives: Part II
Authors: Benkhäuser‐Schunk Christian , Wezisla Boris , Urbahn Kirstin , Kiehne Ulf , Daniels Jörg , Schnakenburg Gregor , Neese Frank , Lützen Arne 
Published: March 2012

AbstractSeven racemic derivatives of Tröger’s base—the 1,7‐dibromo‐substituted derivative 3, the 2,8‐dibromo‐substituted derivative 4, the 2,8‐diiodo‐substituted derivative 5, the 3,9‐diiodo‐substituted derivative 6, the 4,10‐dibromo‐substituted derivative 7, its singly debrominated analogue 8, and the 2,8‐diamino‐substituted derivative 9 in its Fmoc‐protected form—were synthesized and successfully resolved by (recycling) HPLC on a stationary Whelk‐O1 phase at a semipreparative scale. These are valuable functionalized C2‐symmetric building blocks for further applications. Their absolute configurations were determined by X‐ray crystal structure analysis and/or by comparison of their quantum chemically calculated circular dichroism and UV/Vis spectra with the experimental obtained spectra.
Catalytic Oxidation of Toluene and CO over Nanocatalysts Derived from Hydrotalcite‐Like Compounds (X62+Al23+): Effect of the Bivalent Cation
Authors: Genty Eric , Cousin Renaud , Capelle Sylvie , Gennequin Cédric , Siffert Stéphane 
Published: March 2012

AbstractX6Al2HT hydrotalcites, where X represents Fe, Cu, Zn, Ni, Co, Mn or Mg, were synthesized as precursors of catalysts for the toluene and CO total oxidation reactions. Specific area, Fourier transformed infrared spectroscopy analysis, XRD measurements and Thermal analysis of these dried solids were performed. After calcination at 500 °C, different mixed oxides were obtained. The structural analysis (XRD, FTIR) and specific areas of these solids were done. Concerning the total oxidation of toluene, the best activity is obtained with Mn6Al2HT catalyst with T50 at 249 °C. X6Al2 nano‐oxides synthesized using hydrotalcite‐type solids as precursors, are then very promising candidates for an utilisation as CO and VOC oxidation catalysts. The nature of bivalent cation in these compounds is essential for the efficacy of the catalyst.
Relaxivity Enhancement in Macromolecular and Nanosized GdIII‐Based MRI Contrast Agents
Authors: Botta Mauro , Tei Lorenzo 
Published: March 2012

AbstractIn recent years, novel, better, and more complex systems have been developed in which GdIII chelates are attached to macromolecular substrates or incorporated into nanoparticles. These magnetic resonance imaging (MRI) nanoprobes make it possible to deliver to the site of interest a large number of Gd3+ ions, thus increasing the sensitivity of the technique. In this paper, we review the most important systems developed, the conjugation methods, and the procedures devised to optimize the relaxivity. These involve the use of GdIII complexes with higher hydration number, the control of the rate of exchange of the bound water molecule(s), and the reduction of the local rotational motions of the conjugated complexes. The increase in relaxivity of the individual Gd chelates leads to significant relaxivity enhancement of the nanosized systems.
Synthesis, Crystal Structure, and Catecholase Activity of Three Trinuclear Heterometallic NiII2–MnII Complexes Derived from a Salen‐Type Schiff Base Ligand
Authors: Seth Piya , Das Lakshmi K. , Drew Michael G. B. , Ghosh Ashutosh 
Published: March 2012

AbstractThree new trinuclear heterometallic nickel(II)–manganese(II) complexes, [(NiL)2Mn(NCS)2] (1), [(NiL)2Mn(NCO)2] (2), and [{NiL(EtOH)}2Mn(NO2)2]·2EtOH (3), have been synthesized by using [NiL] as the so‐called “ligand complex” [where H2L = N,N′‐bis(salicylidene)‐1,3‐propanediamine] and have been structurally characterized. Crystal structure analyses revealed that complexes 1 and 2 are angular trinuclear species, in which two terminal four‐coordinate square planar [NiL] moieties are coordinated to a central MnII through double phenoxido bridges. The MnII is in a six‐coordinate distorted octahedral environment that is bonded additionally to two mutually cis nitrogen atoms of terminal thiocyanate (in 1) and cyanate (in 2). In complex 3, in addition to the double phenoxo bridge, the two terminal NiII ions are linked to the central MnII by means of a nitrite bridge (1κN:2κO) that, together with a coordinated ethanol molecule, gives rise to an octahedral environment around the NiII ions and consequently the structure becomes linear. Catecholase activity of these three complexes was examined by using 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) as the substrate. All three complexes mimic catecholase activity and the rate of catechol oxidation follows saturation kinetics with respect to the substrate and first‐order kinetics with respect to the catalyst. The EPR spectra of the complexes exhibit characteristic six line spectra, which indicate the presence of high‐spin octahedral MnII species in solution state. The ESI‐MS positive spectrum of 1 in the presence of 3,5‐DTBC has been recorded to investigate possible complex–substrate intermediates.
TROP2 is epigenetically inactivated and modulates IGF‐1R signalling in lung adenocarcinoma
Authors: Lin Jau‐Chen , Wu Yi‐Ying , Wu Jing‐Yi , Lin Tzu‐Chieh , Wu Chen‐Tu , Chang Yih‐Leong , Jou Yuh‐Shan , Hong Tse‐Ming , Yang Pan‐Chyr 
Published: March 2012

AbstractTrop‐2, a cell surface glycoprotein, contains both extracellular epidermal growth factor‐like and thyroglobulin type‐1 repeat domains. Low TROP2 expression was observed in lung adenocarcinoma tissues as compared with their normal counterparts. The lack of expression could be due to either the loss of heterozygosity (LOH) or hypermethylation of the CpG island DNA of TROP2 upstream promoter region as confirmed by bisulphite sequencing and methylation‐specific (MS) polymerase chain reaction (PCR). 5‐Aza‐2′‐deoxycytidine treatment on lung cancer cell (CL) lines, CL1‐5 and A549, reversed the hypermethylation status and elevated both TROP2 mRNA and protein expression levels. Enforced expression of TROP2 in the lung CL line H1299 reduced AKT as well as ERK activation and suppressed cell proliferation and colony formation. Conversely, silencing TROP2 with shRNA transfection in the less efficiently tumour‐forming cell line H322M enhanced AKT activation and increased tumour growth. Trop‐2 could attenuate IGF‐1R signalling‐mediated AKT/β‐catenin and ERK activation through a direct binding of IGF1. In conclusion, inactivation of TROP2 due to LOH or by DNA methylation may play an important role in lung cancer tumourigenicity through losing its suppressive effect on IGF‐1R signalling and tumour growth.
Antibody detection of translocations in Ewing sarcoma
Authors: Luo Wen , Milash Brett , Dalley Brian , Smith Richard , Zhou Holly , Dutrow Natalie , Cairns Bradley R. , Lessnick Stephen L. 
Published: March 2012

AbstractThe detection of chromosomal translocations has important implications in the diagnosis, prognosis and treatment of patients with cancer. Current approaches to translocation detection have significant shortcomings, including limited sensitivity and/or specificity, and difficulty in application to formalin‐fixed paraffin‐embedded (FFPE) clinical samples. We developed a new approach called antibody detection of translocations (ADOT) that avoids the shortcomings of current techniques. ADOT combines a transcriptional microarray‐based approach with a novel antibody‐based detection method. ADOT allows for the accurate and sensitive identification of translocations and provides exon‐level information about the fusion transcript. ADOT can detect translocations in poor‐quality unprocessed total ribonucleic acid (RNA). Furthermore, the technique is readily generalizable to detect any potential fusion transcript, including previously undescribed fusions. We demonstrate the feasibility of ADOT by examples in which both known and unknown Ewing sarcoma translocations are identified from cell lines, tumour xenografts and FFPE primary tumours. These results demonstrate that ADOT may be an effective approach for translocation analysis in clinical specimens with significant RNA degradation and may offer a novel diagnostic tool for translocation‐based cancers.→See accompanying article http://dx.doi.org/10.1002/emmm.201200226
Loss probability estimation for OFDM/TDMA‐based wireless systems considering a cascade‐based multifractal traffic model
Authors: Rocha Flávio G.C. , Vieira Flávio H.T. 
Published: March 2012

ABSTRACTIn this paper, we analyze the queueing performance in terms of byte loss rate of an orthogonal frequency‐division multiplexing/time division multiple access based wireless system taking into account the multifractal behaviour of the wireless traffic flows. To this end, first, we show evidences of multifractal characteristics on wireless traffic traces. These findings motivated us to derive a loss probability equation for wireless traffic flows that can be applied to an orthogonal frequency‐division multiplexing/time division multiple access based wireless system. Simulations and comparisons to other methods are carried out to verify the accuracy of the proposed loss probability estimation approach in describing real traffic queueing behaviour. Copyright © 2012 John Wiley & Sons, Ltd.