bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain Pharmacokinetics of Non‐Imidazole Biphenyl H3 Receptor Antagonists: a Liquid Chromatography/Electrospray‐Mass Spectrometry and ex vivo Binding Study in Rats
Authors: Vacondio Federica , Silva Claudia , Flammini Lisa , Ballabeni Vigilio , Barocelli Elisabetta , Mor Marco 
Published: July 2012

AbstractIn the present article, we report on the kinetics of brain penetration in rats of the H3R antagonist 1,1′‐[1,1′‐biphenyl‐4,4′‐diylbis(methylene)]bis‐[piperidine] (1), which had shown a favorable in vitro pharmacological profile and in vivo potency in preventing scopolamine‐induced amnesia. Two different approaches were employed: high‐performance liquid chromatography/electrospray‐mass spectrometry (HPLC/ESI‐MS) and ex vivo binding against the labeled agonist [3H]‐(R)‐α‐methylhistamine ([3H]RAMHA). Starting from the structure of 1, the rigid piperidine ring was replaced by a flexible dipropylamino group (see 2) or by a morpholino ring (see 3), endowed with lower basicity. The effect of replacement on rat plasma and brain disposition in the 24 h after administration was analyzed. High (μM) and persistent concentrations of 1 were found in rat plasma, while plasma levels were significantly lower (range: 0–200 nM) for the other two derivatives. This could be explained, among other factors, by the higher stability, observed for 1, to liver metabolic cleavage. The applied chemical modulation had an important effect on in vivo brain disposition, as, despite the comparable physico‐chemical properties, 2 did not show the tendency to accumulate within the brain, as stated by its brain vs. plasma concentration ratios, if compared to 1. These structureproperty relationships should be taken into account in the pharmacokinetic optimization of new series of H3 receptor antagonists.
Essential‐Oil Diversity of Three Calamintha Species from Greece
Authors: Karousou Regina , Hanlidou Effie , Lazari Diamando 
Published: July 2012

AbstractThe aim of the present study was to contribute to the knowledge of the essential‐oil composition of the Calamintha officinalis‐nepeta complex in Greece and to clarify the main patterns of its variation. The oils obtained from 22 wild‐growing populations of C. glandulosa, C. nepeta, and C. menthifolia were studied. They could be classified into two different chemotypes, which correspond to the main biosynthetic routes of the C(3)‐oxygenated p‐menthane compounds. Chemotype I includes oils rich in trans‐piperitone oxide, cis‐piperitone oxide, and piperitenone oxide, while Chemotype II comprises oils rich in pulegone and menthone or menthone and isomenthone. Within both chemotypes, quantitative fluctuations of the main components were observed. Comparison with published data showed that the presence of Chemotype II has not been observed before in C. menthifolia, while Chemotype I has been reported in C. nepeta plants from Greece for the first time.
Comparative Chemical and Molecular Variability of Cananga odorata (Lam.) Hook.f. & Thomson forma genuina (Ylang‐Ylang) in the Western Indian Ocean Islands: Implication for Valorization
Authors: Benini Céline , Mahy Grégory , Bizoux Jean‐Philippe , Wathelet Jean‐Paul , du Jardin Patrick , Brostaux Yves , Fauconnier Marie‐Laure 
Published: July 2012

AbstractCananga odorata (Lam.) Hook.f. & Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang‐ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang‐ylang grown in semi‐managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang‐ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations.
The Influence of the Substitution Pattern on the Molecular Conformation of Ureido‐1,2,5‐oxadiazoles, Related to STAT3 Inhibitors: Chemical Behavior and Structural Investigation
Authors: Villa Stefania , Masciocchi Daniela , Gelain Arianna , Meneghetti Fiorella 
Published: July 2012

AbstractSignal transducer and activator of transcription 3 (STAT3) is a protein constitutively activated by aberrant upstream tyrosine kinase activities in a broad spectrum of human solid and blood tumors. Therefore, the availability of drugs affecting STAT3 may have important therapeutic potential for the treatment of cancer. Pursuing our efforts in exploring the influence of the substitution pattern of the ureido 1,2,5‐oxadiazole moiety on the molecular conformation, new compounds substituted at positions 3 and 4 on the furazane ring were synthesized. The inhibition properties vs. STAT3 of the novel compounds were evaluated in a dual‐luciferase assay, using HCT‐116 cells, and the results evidenced a moderate activity only for the compounds endowed with a planar arrangement. Crystallographic studies of the new derivatives were performed in order to evidence the peculiar chemical behavior and to evaluate how structural modulations affected the biological properties.
Magnesium(I) Dimers as Reagents for the Reductive Coupling of Isonitriles and Nitriles
Authors: Ma Mengtao , Stasch Andreas , Jones Cameron 
Published: July 2012

AbstractThe reactivity of two β‐diketiminate coordinated magnesium(I) dimers, [LMgMgL], L=[(RNCMe)2CH]−, R=C6H3iPr2‐2,6 (DipNacnac−) or mesityl (MesNacnac−), towards a series of isonitriles and nitriles have been examined. Reactions with the isonitriles, RNC: (R=tBu or C6H3Me2‐2,6 (Xyl)), led to reductive CC couplings and the formation of [{(DipNacnac)Mg}2{μ‐(XylN=C‐)2}] and [{(MesNacnac)Mg}2{μ‐(tBuN=C‐)2}], or a reductive NC cleavage and the generation of the magnesium cyanide complex, [{(DipNacnac)Mg(μ‐CN)}3]. Reactions of the magnesium dimers with benzonitrile, PhCN, afforded the CC‐coupled products, [(DipNacnac)Mg[μ‐{N=C(Ph)‐}2]Mg(NCPh)(DipNacnac)], and [{{(MesNacnac)Mg}2[μ‐{N=C(Ph)‐}2]}2], whereas the reductive CC cleavage of tBuCN gave rise to a mixture of [(DipNacnac)Mg(tBu)(NCtBu)] and [{(DipNacnac)Mg(μ‐CN)}3]. In contrast, a combination of net nitrile isomerization and CC coupling processes was involved in the reduction of Me3SiCN, which yielded [{(DipNacnac)Mg}2{μ‐(Me3SiN=C‐)2}]. All new compounds were crystallographically and spectroscopically characterized. The outcomes of the reported reactions were found to be dependent upon both the steric bulk of the magnesium(I) reagent, and the nature of the isonitrile/nitrile substituent. This combined with a high degree of selectivity for the reactions, indicates that magnesium(I) dimers may find use by organic and organometallic chemists as viable alternatives to currently available reducing agents that are utilized for the reduction of unsaturated organic substrates.
Addressing Challenges in Palladium‐Catalyzed Cross‐Coupling Reactions Through Ligand Design
Authors: Lundgren Rylan J. , Stradiotto Mark 
Published: July 2012

AbstractThe development of palladium‐catalyzed cross‐coupling reactions has revolutionized the synthesis of organic molecules on both bench‐top and industrial scales. While significant research effort has been directed toward evaluating how modifying various reaction parameters can influence the outcome of a given cross‐coupling reaction, the design and implementation of novel ancillary ligand frameworks has played a particularly important role in advancing the state‐of‐the‐art. This Review seeks to highlight notable examples from the recent chemical literature, in which newly developed ancillary ligands have enabled more challenging substrate transformations to be addressed with greater selectivity and/or under increasingly mild conditions. Throughout, the importance and subtlety of ligand effects in palladium‐catalyzed cross‐coupling reactions are described, in an effort to inspire further development and understanding within the field of ancillary ligand design.
Polyphenol Recovery from Olive Mill Wastewater via Membrane Technology
Authors: Peters Martin , Mudimu Ompe Aimé , Brauner Florian , Braun Gerd 
Published: July 2012

AbstractOlivenmühlenabwasser (OMW) fällt als Nebenprodukt der Olivenölproduktion jedes Jahr in großen Mengen nach der Olivenernte hauptsächlich in der mediterranen Region an. Problematisch ist die hohe Belastung mit organischen Bestandteilen, wie phytotoxischen Polyphenolen, die beträchtliche Umweltschäden hervorrufen können. Andererseits werden einige Polyphenole aufgrund ihrer antioxidativen Eigenschaften in vielen Industriebranchen, z. B. zur Herstellung von Kunststoffen, Kosmetika und Medikamenten, genutzt. Eine kombinierte Wasseraufbereitung erlaubt neben der Wasserreinigung auch die Rückgewinnung der enthaltenen Polyphenolverbindungen zur industriellen Nutzung. Eine Möglichkeit bietet hier die Membrantechnik. Im Folgenden wird ein Überblick über den Stand der Forschung zur Polyphenolrückgewinnung aus OMW mittels Membrantechnologien gegeben.
Numerical Investigations and Experiments for the Analysis of Mixing of Highly Viscous Fluids in a Rotor‐Stator Mixer
Authors: Smuda Christina , Piesche Manfred 
Published: July 2012

AbstractMithilfe der numerischen Strömungsmechanik, unterstützt durch Experimente, wurde ein Rotor‐Stator‐Mischer hinsichtlich seines Betriebs‐ und Mischverhaltens untersucht. Für die isoviskose Vermischung konnten Ähnlichkeitsgesetze hergeleitet werden, die das Betriebsverhalten in Form dimensionsloser Kennzahlen beschreiben. Der Vergleich der Ergebnisse aus der numerischen Strömungssimulation mit den experimentellen Daten zeigt eine gute Übereinstimmung. In weiteren Simulationen und Experimenten wurden außerdem das Volumenstrom‐ und das Viskositätsverhältnis der zu vermischenden Komponenten mit newtonschen Stoffeigenschaften variiert und deren Einfluss auf die Mischgüte analysiert.
Plastics – Granulate and/or Pelletize?
Authors: Mürb Reinhardt‐Karsten 
Published: July 2012

AbstractDie vermeintlich einfache verfahrenstechnische Operation zur Herstellung von Kunststoffgranulat eröffnet bei näherer Betrachtung eine Vielfalt von einzelnen Aspekten. Trotz vieler, meist empirischer Untersuchungen gibt es noch viel zu erforschen. Dabei werden von Produkt und Werkzeugen viele Teildisziplinen berührt: Materialwissenschaften, Thermodynamik, Rheologie, Festigkeitslehre, Tribologie, Maschinenlehre etc. Granulieren oder Pelletieren sind Mittel zum Zweck, um den Kunststoff in eine transportier‐ und dosierbare Form zu bringen. Der Beitrag vergleicht die Verfahren und weist auf Potenziale für weiterführende wissenschaftliche Untersuchungen hin.
Research Secures Raw Materials for High‐Tech Made in Germany
Authors: Mennicken Lothar , Jacobi Andreas , Degenhardt Anja 
Published: July 2012

AbstractDie deutsche Bundesregierung hat mit ihrer Rohstoffstrategie auf mögliche Engpässe bei nicht‐energetischen, mineralischen Rohstoffen reagiert. Das Bundesministerium für Bildung und Forschung (BMBF) unterstützt die ressortübergreifende Strategie sowohl mit seiner institutionellen Förderung als auch mit der spezifischen Projektförderung. Das neue FuE‐Programm Wirtschaftsstrategische Rohstoffe für den Hightech‐Standort Deutschland ist wegweisend. Verschiedene rohstoffbezogene Fördermaßnahmen innerhalb des BMBF‐Rahmenprogramms Forschung für nachhaltige Entwicklungen werden beschrieben.
B(C6F5)3 as a Highly Effective Catalyst for the Phosphoryl Transfer Reaction
Authors: Xue Weihua , Zhang Lifen 
Published: July 2012

AbstractThe phosphoryl transfer reactions of diphenyl chlorophosphate with a wide range of alcohols were catalyzed by tris(pentafluorophenyl)boron [B(C6F5)3], giving the corresponding phosphate esters in excellent yields. This methodology has advantages over older ones because it employs the easily handled B(C6F5)3, avoids the side reaction, and has shorter reaction time.
DNA‐Templated Silver Nanoclusters Formation at Gold Electrode Surface and Its Application to Hydrogen Peroxide Detection
Authors: Xu Yuanyuan , Chen Yangyang , Yang Nana , Sun Lizhou , Li Genxi 
Published: July 2012

AbstractIn this work, we have prepared Ag nanoclusters (Ag NCs) at gold electrode surface by using thiol‐modified oligodeoxynucleotide consisting of eighteen cytosine deoxyribonucleotides (polyC18) as template and NaBH4 as reducing agent. Experimental results show that Ag nanoclusters (Ag NCs) can be formed around the template polyC18, while the formation can be characterized with electrochemical method. Further studies reveal that the fabricated Ag NCs may display high catalytic activity for the reduction of hydrogen peroxide (H2O2), which can be further used for the detection of H2O2.
Designs, Synthesis, Characterization and Direct Electrochemistry of Zinc‐Porphyrin Bearing Pyrene Noncovalent Functionalized Graphene Oxide Sheet
Authors: Bi Chun , Li Yongjie , Chen Haowen , Yin Gui , Zhu Junjie 
Published: July 2012

AbstractWe have designed and synthesis a new compound of zinc‐porphyrin bearing four pyrene groups (ZnP‐t‐P(py)4) and prepared a new hybrid materials of ZnP‐t‐P(py)4 with graphene oxide (GO) via non‐covalent interactions. The ZnP‐t‐P(py)4, along with four pendant pyrene entities ZnP‐t‐P(py)4, stacking on the (GO) surface due to π‐ π interactions, has been revealed by AFM measurements. FTIR, UV‐vis absorption confirm the non‐covalent functionalization of the GO. Raman spectral measurements revealed the electronic structure of the GO to be intact upon hybrid formation. In this donor‐acceptor nanohybrid, the fluorescence of photoexcited ZnP‐t‐P(py)4 is effectively quenched by a possible electron‐transfer process. The fluorescence and photoelectrical response measurements also showed that this hybrid may act as an efficient photoelectric conversion material for optoelectronic applications.
Photoelectrochemical Detection of Glucose by Using an Enzyme‐Modified Photoelectrode
Authors: Zhao Changzhi , Zhang Zhaoxia , Zhao Ying , Yu Jia 
Published: July 2012

AbstractA new photoelectrochemical method for the determination of glucose based on the photoelectrochemical effect of poly(thionine) photoelectrode to hydrogen peroxide (H2O2) was reported. The H2O2‐sensitive photoelectrode was fabricated by electropolymerizing thionine on the surface of ITO electrode. And then glucose oxidase was immobilized on the photoelectrode via the aid of chitosan enwrapping, forming an enzyme‐modified photoelectrode. The photoelectrode was employed as an electron acceptor; H2O2 from the catalytic reaction of enzyme was employed as an electron donor, developing an analytical method of glucose without hydrogen peroxidase. In the paper, the photoelectrochemical effects of photoelectrode to H2O2 and glucose were studied. The effects of the bias voltage and the electrolyte pH on the photocurrent were investigated. The linear response of glucose concentrations ranged from 0.05 to 2.00 mmol/L was obtained with a detection limit of 22.0 µmol/L and sensitivity of 73.2 nA/(mmol·L−1). The applied feasibility of method was acknowledged through monitoring the glucose in practical samples.
Genetic and epigenetic alterations in primary colorectal cancers and related lymph node and liver metastases
Authors: Miranda Elena , Bianchi Paolo , Destro Annarita , Morenghi Emanuela , Malesci Alberto , Santoro Armando , Laghi Luigi , Roncalli Massimo 
Published: July 2012

AbstractBACKGROUND:Colorectal cancer (CRC) prognosis and survival are strictly related to the development of distant metastases. New targeted therapies have increased patient survival, but the objective response rate is still very limited, partially because of a traditional focus on designing treatment according to the molecular profile of the primary tumor regardless the diversity between the primary tumor and metastases. The objective of this study was to evaluate the presence of molecular heterogeneity during metastatic progression and its potential impact on clinical treatment.METHODS:The authors analyzed v‐Ki‐ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) codon 12 mutations, the v‐Raf murine sarcoma viral oncogene homolog B1 (BRAF) thymine to adenine substitution at codon 1788, and tumor protein 53 (p53) mutations and investigated promoter methylation of Ras association (RalGDS/AF‐6) domain family member 1 protein (RASSF1a), E‐cadherin, and cyclin‐dependent kinase inhibitor 2A (p16INK4a) in 101 primary CRCs (67 stage III and 34 stage IV) and related lymph node and liver metastases.RESULTS:Lymph node metastases were characterized by fewer alterations compared with primary tumors and liver metastases, especially KRAS (P = .03) and p16INK4a (P = .05). Genetic changes, when detectable in metastases, mostly were retained from the primary tumor, whereas epigenetic changes more frequently were acquired de novo. Overall, 31 distinct CRC molecular profiles were detected, none of which characterized a particular tumor stage. When the metastatic lesions also were included in the profiles, there were 53 distinct molecular profiles in 67 patients with stage III disease and 34 distinct molecular profiles in 34 patients with stage IV disease.CONCLUSIONS:Lymph node and liver metastases appear to originate in clonally different processes, with more molecular alterations occurring in distant metastases than in lymph node metastases and with elevated heterogeneity of the primary tumor. Thus, potential prognostic targets should be carefully evaluated for their heterogeneity in both primary tumors and distant metastases to avoid erroneous misclassification. Cancer 2013. © 2012 American Cancer Society.
Chalcogenoalkynes: Precursors for the Regioselective Preparation of 2‐Chalcogeno‐1‐halonaphthalenes through [4+2] Cycloaddition
Authors: Mantovani Anderson C. , Back Davi F. , Zeni Gilson 
Published: July 2012

AbstractChalcogenoalkynes and o‐alkynylbenzaldehydes reacted in the presence of copper(II) salt to give the [4+2] cycloadducts 2‐chalcogeno‐1‐halonaphthalenes in good yields (46–89 %) and high regioselectivities. The methodology was carried out by using CuCl2 or CuCl2/LiBr in 1,2‐dichloroethane (DCE) at 80 °C. The potential and generality of this system was evaluated by using a variety of chalcogenoalkynes including aromatic, substituted aromatic, and aliphatic substrates having both sulfur and selenium atoms. In this sequence, due to the ability of the chalcogen atoms to stabilize charges, these substituents exert regiocontrol that guides the selectivity.
Apixaban: a new option for stroke prevention in atrial fibrillation?
Authors: Cox Andrew , Ghani Saqib , Camm A John 
Published: July 2012

AbstractAtrial fibrillation is the most common sustained cardiac arrhythmia and its prevalence is set to double by 2050. Of the possible treatments for the condition, only antithrombotic therapy has demonstrated a mortality benefit. Until recently, the gold‐standard treatment was warfarin; in those patients for whom this was contraindicated, aspirin was used. However, over the last two years, several new agents have been developed, the most recent of which is the factor Xa inhibitor apixaban [Eliquis]. Two large randomised controlled trials comparing apixaban with aspirin and warfarin were recently reported. This Drug profile outlines the significant benefits of apixaban in reducing mortality, stroke risk and major bleeding events in atrial fibrillation.
Terpenoids from Loxocalyx urticifolius
Authors: He Dahai , Xu Xuemin , Zhou Yan , Deng Wenlong , Xia Bin , Ding Lisheng 
Published: July 2012

AbstractTwo new diterpenoids, loxocalyxin A (1) and 13‐epiloxocalyxin A (2), and two new sesquiterpenoids, loxocalyxins B and C (3 and 4, resp.), together with three known compounds, were isolated from the MeOH extract of the whole plant of Loxocalyx urticifolius Hemsl. The structures of the new compounds were established by means of spectroscopic analysis including one‐ and two‐dimensional NMR spectroscopy. All new structures were confirmed by X‐ray crystallographic analysis. Their absolute configurations were established.
Ultrasound‐Promoted Catalyst‐Free Synthesis of 2,2′‐(1,4‐Phenylene)bis[1‐acetyl‐1,2‐dihydro‐4H‐3,1‐benzoxazin‐4‐one] Derivatives
Authors: Azarifar Davood , Sheikh Davood 
Published: July 2012

AbstractA convenient approach to 2,2′‐(1,4‐phenylene)bis[1‐acetyl‐1,2‐dihydro‐4H‐3,1‐benzoxazin‐4‐one] derivatives 4 was explored employing the one‐pot condensation of anthranilic acids (=2‐aminobenzoic acids) 1 with terephthalaldehyde (=benzene‐1,4‐dicarboxaldehyde; 2) under ultrasound‐irradiation conditions (Scheme 1). The reactions proceeded smoothly in the presence of excess Ac2O in the absence of any other catalyst and solvent to afford the respective products in high yields.
Mechanistic Investigation of the Ring Opening in the Staudinger Cycloaddition Involving Ketenes with Electron‐Withdrawing Substituents
Authors: Mo Shanyan , Xu Jiaxi 
Published: July 2012

AbstractThe cycloaddition of ketenes and imines (Staudinger cycloaddition) is a general method for the synthesis of various β‐lactams. However, reactions of imines and ketenes with electron‐withdrawing substituents produce α,β‐unsaturated alkenamides, ring‐opening products of the intermediates generated from imines and the ketenes, even as sole products, besides the desired β‐lactams. The mechanism of the formation of α,β‐unsaturated alkenamides was investigated. The results indicate that the α,β‐unsaturated alkenamides are generated via a base‐induced CC bond isomerization followed by electrocyclic ring opening of the formed azacyclobutenes (=1,2‐dihydroazetes; cf. Scheme 3).
Stereoselective Total Synthesis of Botryolide E
Authors: Veeranjaneyulu Boyapati , Srilatha Malampati , Reddy Gandolla Chinna , Das Biswanath 
Published: July 2012

AbstractThe stereoselective total synthesis of the naturally occurring γ‐lactone derivative botryolide E (1) was accomplished with acetaldehyde as the starting material (Scheme 2). The asymmetric allyl boration, asymmetric dihydroxylation, chelation‐mediated diastereoselective vinylation, and ring‐closing metathesis reaction are the key steps. The method can conveniently be utilized for the preparation of other related γ‐lactone derivatives.
Three New Sucrose Fatty Acid Esters from Equisetum hiemale L.
Authors: Cheng Jin‐Tang , He Juan , Li Xing‐Yao , Wu Xing‐De , Shao Li‐Dong , Dong Liao‐Bin , Deng Xu , Gao Xiu , Peng Li‐Yan , Cheng Xiao , Li Yan , Zhao Qin‐Shi 
Published: July 2012

AbstractThree new monosubstituted sucrose fatty acid esters, 1–3, were isolated from Equisetum hiemale L., together with nine known compounds, 4–12. Their structures were elucidated by spectroscopic analyses. Compounds 5, 6, and 10–12 were isolated from the title plant for the first time. All these compounds were evaluated for their cytotoxic activity. However, none of them was cytotoxic.
A Novel One‐Pot Synthesis of Fully Substituted Thiophen‐2(3H)‐ones Using N,N‐Disubstituted Thioamides
Authors: Zali‐Boeini Hassan , Pourjafarian Fatemeh 
Published: July 2012

AbstractA new one‐step synthesis of highly substituted thiophen‐2(3H)‐one derivatives was developed. 2‐Aryl‐1‐(morpholin‐4‐yl)ethanethiones were reacted with 2‐chloro‐2‐phenylacetyl chloride in DMF in the presence of a base to give the title compounds in moderate‐to‐good yields.