bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Direct Aerobic Oxidation of 2‐Benzylpyridines in a Gas—Liquid Continuous‐Flow Regime Using Propylene Carbonate as a Solvent.
Authors: Pieber Bartholomaeus , Kappe C. Oliver 
Published: April 2013

AbstractThe use of high temperature/pressure gas‐liquid continuous flow conditions significantly enhance the iron‐catalyzed aerobic oxidation of benzylpyridines (I) to the corresponding ketones (II).
ChemInform Abstract: Palladium‐Catalyzed Insertion of α‐Diazocarbonyl Compounds for the Synthesis of Cyclic Amino Esters.
Authors: Zhou Ping‐Xin , Zhou Zhao‐Zhao , Chen Zi‐Sheng , Ye Yu‐Ying , Zhao Lian‐Biao , Yang Yan‐Fang , Xia Xiao‐Feng , Luo Jian‐Yi , Liang Yong‐Min 
Published: April 2013

AbstractTwo different cyclic amino esters (IV) and (VI) are synthesized by Pd‐catalyzed cross‐coupling reaction of diazoesters (II) and (V) with N‐substituted 2‐iodoanilines (I).
ChemInform Abstract: Conversion of 2,3‐Dihydroxynaphthazarins to Isoquinoline‐1,3,4(2H)‐trione Derivatives.
Authors: Borisova K. L. , Mel'man G. I. , Denisenko V. A. , Glazunov V. P. , Anufriev V. F. 
Published: April 2013

AbstractThe reaction pathway of title conversion leading to compounds [(II) and (III)] or [(V) and (VI)], resp., is greatly controlled by the hydroxy groups at C‐6 and C‐7.
ChemInform Abstract: Efficient Synthesis of Novel 3‐(5‐(2‐Hydroxy‐2‐phenylethylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl) ‐1,8‐naphthyridin‐4(1H)‐ones.
Authors: Chaitanya Muggu V. S. R. K. , Venkateshwarlu Pilli , Dubey Pramod K. 
Published: April 2013

AbstractThe preparation of β‐keto sulfones (VII) and β‐hydroxy sulfones (VIII) is elaborated starting from hydrazides (I).
ChemInform Abstract: Facile Biginelli‐Type Reactions Catalyzed by Super Acidic Ionic Liquid under Solvent‐Free Conditions.
Authors: Wang Liang , Zhou Min , Chen Qun , He Ming‐Yang 
Published: April 2013

AbstractThe super acidic ionic liquid Me—C(OH)2+ClO4‐, prepared by mixing acetic acid and perchloride acid at room temperature, is shown to be an extremely active catalyst for the synthesis of dihydropyrimidine derivatives via Biginelli‐type reactions.
ChemInform Abstract: Divergent Synthesis of Functionalized Carbocycles Through Organosilane‐Directed Asymmetric Alkyne—Alkene Reductive Coupling and Annulation Sequence.
Authors: Wu Jie , Pu Yi , Panek James S. 
Published: April 2013

AbstractReductive coupling of propargylsilanes with alkenols is found to result in efficient and stereoselective formation of functionalized allylsilanes such as (III), (X), and (XIII).
ChemInform Abstract: Synthesis of 2‐Pyridylphosphinate and Thiophosphinate Derivatives by Nucleophilic Aromatic Substitution of N‐Methoxypyridinium Tosylates.
Authors: Oka Natsuhisa , Ito Kousuke , Tomita Futoshi , Ando Kaori 
Published: April 2013

AbstractThe presented approach could be a cost‐effective alternative for the synthesis of 2‐pyridylphosphinates, which are currently synthesized by rather expensive Pd‐catalyzed cross‐coupling.
ChemInform Abstract: Palladium‐Catalyzed Vinylselenation of Allenes.
Authors: Fujiwara Shin‐ichi , Okuyama Maiko , Tsuda Susumu , Iwasaki Takanori , Kuniyasu Hitoshi , Kambe Nobuaki 
Published: April 2013

AbstractPd‐cataylzed treatment of allenes with activated vinyl selenides is found to result in efficient and regioselective formation of 2‐selenomethyl‐1,3‐dienes.
ChemInform Abstract: An Efficient and General Procedure for the Synthesis of Alkynyl Chalcogenides (Selenides and Tellurides) by Alumina‐Supported Cu(II)‐Catalyzed Reaction of Alkynyl Bromides and Diphenyl Dichalcogenides.
Authors: Ahammed Sabir , Bhadra Sukalyan , Kundu Debasish , Sreedhar Bojja , Ranu Brindaban C. 
Published: April 2013

AbstractDialkyl dichalcogenides also undergo successful reaction.
ChemInform Abstract: Selenenylations of Alkenes with Styrene Nucleophiles.
Authors: Gabriele Elena , Singh Fateh V. , Freudendahl Diana M. , Wirth Thomas 
Published: April 2013

AbstractIodine‐ and bromine‐mediated treatment of diaryl diselenides with styrene and electron‐rich analogues results in formation of new 2:1 adducts like (III), (VII), and (X).
ChemInform Abstract: Stereoselective Synthesis of Pseudoglycosides Catalyzed by TeCl4 under Mild Conditions.
Authors: Freitas Juliano C. R. , Couto Tulio R. , Paulino Antonio A. S. , de Freitas Filho Joao R. , Malvestiti Ivani , Oliveira Roberta A. , Menezes Paulo H. 
Published: April 2013

AbstractIt is found that TeCl4 efficiently promotes the glycosylation of glycals giving a number of pseudoglycosides including dimeric pyranosides with moderate to high stereoselectivity.
ChemInform Abstract: Antiproliferative and Apoptotic Effects of Compounds from the Flower of Mammea siamensis (Miq.) T. Anders. on Human Cancer Cell Lines.
Authors: Tung Nguyen Huu , Uto Takuhiro , Sakamoto Ayana , Hayashida Yuka , Hidaka Yuuki , Morinaga Osamu , Lhieochaiphant Sorasak , Shoyama Yukihiro 
Published: April 2013

AbstractThe new geranylated coumarin mammeanoyl (I) and seven known compounds are isolated from the title flowers.
ChemInform Abstract: Manzamenones L—N, New Dimeric Fatty‐Acid Derivatives from an Okinawan Marine Sponge Plakortis sp.
Authors: Kubota Takaaki , Ishiguro Yuichiro , Takahashi‐Nakaguchi Azusa , Fromont Jane , Gonoi Tohru , Kobayashi Jun'ichi 
Published: April 2013

AbstractThe isolated new polyketides manzamenones L—N [(I) and (II)] are screened for their antimicrobial activity.
ChemInform Abstract: Chemical Vapour Deposition of CNTs Using Structural Nanoparticle Catalysts
Authors: Ayre G. N. , Uchino T. , Mazumder B. , Hector A. L. , Smith D. C. , Ashburn P. , de Groot C. H. , Hutchison J. L. 
Published: April 2013

AbstractReview: (CNT: carbon nanotube) 74 refs.
Production of 1‐Octanol from n‐Octane by Pseudomonas putida KT2440
Authors: Vallon Tobias , Glemser Matthias , Malca Sumire Honda , Scheps Daniel , Schmid Joachim , Siemann‐Herzberg Martin , Hauer Bernhard , Takors Ralf 
Published: April 2013

AbstractA two‐phase biotransformation process for selective hydroxylation of n‐octane to 1‐octanol via Pseudomonas putida KT2440 harboring heterologously expressed P450 monooxygenase from Mycobacterium marinum is presented. Maximum cell‐specific conversion rates of 12.7 mgoctanol gCDWh–1 were observed not only in shaking flasks but also in 3.7‐L‐bioreactor studies. The bioreactor experiments were performed avoiding explosive gas mixtures by lowering volumetric power input, aeration rates and substrate concentrations. Based on a stoichiometric network of P. putida KT2440 topological studies were carried out. As a conclusion, potential limitations of NAD(P)H and/or ATP supply at production conditions can be excluded. Hence, the great potential of the host for further increasing conversion is outlined.
Effect of Water Flow Rate on Decontamination Efficiency of Emergency Safety Showers
Authors: Brock Thomas H. , Heil Volker , Philipp Hermann , Seifert Ulrich , Steffens Wilfried , Timm Kurt 
Published: April 2013

AbstractNormen für Überkopf‐Personennotduschen in Laboratorien und Betrieben zum Abspülen von Gefahrstoffkontaminationen stellen Anforderungen an das Sprühbild und an den Wasservolumenstrom – bislang ohne wissenschaftlich gesicherte Grundlage. In einer praxisorientierten Untersuchung an 15 anwendungsüblichen Duschköpfen wurde die Abspülwirkung für wasserlösliche Kontaminanten bei 20 bis 110 L min–1 Wasservolumenstrom untersucht. Ein Zusammenhang zwischen Wirkung und Volumenstrom konnte nicht gezeigt werden: Bei 30 L min–1 Wasser ist die Abspülzeit nicht generell länger als bei wesentlich höheren Volumenströmen. Die kürzeste Abspülzeit wurde an Notduschen mit nicht‐normkonformem Sprühbild gefunden.
Hydrodynamic Studies in Slurry Bubble Columns: Experimental and Numerical Study
Authors: Rabha Swapna , Schubert Markus , Hampel Uwe 
Published: April 2013

AbstractTo overcome the current difficulties in designing a slurry bubble column (SBC) reactor with respect to the effect of particle properties, the influence of solid concentration (Cs) on the hydrodynamics of a SBC was studied experimentally using ultrafast electron beam X‐ray tomography. The real time gas flow structure, average bubble diameter and average gas holdup as a function of the superficial gas velocity and Cs have been reported. Corresponding three‐phase simulations were also performed using the Euler‐Euler multi‐fluid model implemented in CFX 14. The bubble size distribution was calculated using the MUSIG model. The predicted gas holdup and bubble size distribution also show dependence on UG and Cs and agree well with the measurements.
A vertical‐loop‐array transmit coil for two‐channel B1 shimming at 3T
Authors: Kang Lae Hoon , Park Yong Moon , Kim Dong Eun , Lee Soo Yeol 
Published: April 2013

ABSTRACTWe propose a whole‐body transmit coil structure for two‐channel B1 shimming at 3T. The transmit coil consists of four identical vertical‐loop‐coils placed on a cylindrical former by equiangular basis. A vertical loop coil consists of an inner‐conductor plane and an outer‐conductor plane both of which constitute a vertical loop when the two planes are connected by tuning capacitors at both ends. To improve the B1 homogeneity of the transmit coil, we split the inner‐ and outer‐conductor planes into two rungs. We made the transmit coil with the length of 500 mm on a frame that had the inner and outer diameters of 550mm and 600mm, respectively. In the B1 shimming experiment with the transmit coil, we drove the coil with two RF power amplifiers of 18kWp each through two quadrature hybrids. Before the B1 shimming, we performed B1 mapping for each driving channel, and then, we determined the optimal magnitude and phase of the input signals to the RF power amplifiers. In the B1 shimming experiment on a human‐body‐mimicking phantom, the optimized transmission improved the image uniformity by 24.7% as compared to the conventional quadrature transmission. © 2013 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 43B: 59–68, 2013
Controlling the π‐Stacking Behavior of Pyrene Derivatives: Influence of H‐Bonding and Steric Effects in Different States of Aggregation
Authors: Haedler Andreas T. , Misslitz Holger , Buehlmeyer Christian , Albuquerque Rodrigo Q. , Köhler Anna , Schmidt Hans‐Werner 
Published: April 2013

AbstractThe performance of opto‐electronic devices built from low‐molecular‐weight dye molecules depends crucially on the stacking properties and the resulting coupling of the chromophoric systems. Herein we investigate the influence of H‐bonding amide and bulky substituents on the π‐stacking of pyrene‐containing small molecules in dilute solution, as supramolecular aggregates, and in the solid state. A set of four pyrene derivatives was synthesized in which benzene or 4‐tert‐butyl benzene was linked to the pyrene unit either through an ester or an amide. All four molecules form supramolecular H‐aggregates in THF solution at concentrations above 1×10−4 mol L−1. These aggregates were transferred on a solid support and crystallized. We investigate: the excimer formation rates within supramolecular aggregates; the formation of H‐bonds as well as the optical changes during the transition from the amorphous to the crystalline state; and the excimer to monomer fluorescence ratio in crystalline films at low temperatures. We reveal that in solution supramolecular aggregation depends predominantly on the pyrene chromophores. In the crystalline state, however, the pyrene stacking can be controlled gradually by H‐bonding and steric effects. These results are further confirmed by molecular modeling. This work bears fundamental information for tailoring the solid state of functional optoelectronic materials.
Conversion of Cellulose and Cellobiose into Sorbitol Catalyzed by Ruthenium Supported on a Polyoxometalate/Metal–Organic Framework Hybrid
Authors: Chen Jinzhu , Wang Shengpei , Huang Jing , Chen Limin , Ma Longlong , Huang Xing 
Published: April 2013

AbstractCellulose and cellobiose were selectively converted into sorbitol over water‐tolerant phosphotungstic acid (PTA)/metal– organic‐framework‐hybrid‐supported ruthenium catalysts, Ru‐PTA/MIL‐100(Cr), under aqueous hydrogenation conditions. The goal was to investigate the relationship between the acid/metal balance of bifunctional catalysts Ru‐PTA/MIL‐100(Cr) and their performance in the catalytic conversion of cellulose and cellobiose into sugar alcohols. The control of the amount and strength of acid sites in the supported PTA/MIL‐100(Cr) was achieved through the effective control of encapsulated‐PTA loading in MIL‐100(Cr). This design and preparation method led to an appropriately balanced Ru‐PTA/MIL‐100(Cr) in terms of Ru dispersion and hydrogenation capacity on the one hand, and acid site density of PTA/MIL‐100(Cr) (responsible for acid‐catalyzed hydrolysis) on the other hand. The ratio of acid site density to the number of Ru surface atoms (nA/nRu) of Ru‐PTA/MIL‐100(Cr) was used to monitor the balance between hydrogenation and hydrolysis functions; the optimum balance between the two catalytic functions, that is, 8.84<nA/nRu<12.90, achieves maximum conversion of cellulose and cellobiose into hexitols. Under the applied reaction conditions, optimal results (63.2 % yield in hexitols with a selectivity for sorbitol of 57.9 % at complete conversion of cellulose, and 97.1 % yield in hexitols with a selectivity for sorbitol of 95.1 % at complete conversion of cellobiose) were obtained using a Ru‐PTA/MIL‐100(Cr) catalyst with loadings of 3.2 wt % for Ru and 16.7 wt % for PTA. This research thus opens new perspectives for the rational design of acid/metal bifunctional catalysts for biomass conversion.
Parallel and non‐parallel morphological divergence among foraging specialists in European whitefish (Coregonus lavaretus)
Authors: Siwertsson Anna , Knudsen Rune , Adams Colin E. , Præbel Kim , Amundsen Per‐Arne 
Published: April 2013

AbstractParallel phenotypic evolution occurs when independent populations evolve similar traits in response to similar selective regimes. However, populations inhabiting similar environments also frequently show some phenotypic differences that result from non‐parallel evolution. In this study, we quantified the relative importance of parallel evolution to similar foraging regimes and non‐parallel lake‐specific effects on morphological variation in European whitefish (Coregonus lavaretus). We found evidence for both lake‐specific morphological characteristics and parallel morphological divergence between whitefish specializing in feeding on profundal and littoral resources in three separate lakes. Foraging specialists expressed similar phenotypes in different lakes in both overall body shape and selected measured morphological traits. The morphology of the two whitefish specialists resembled that predicted from other fish species, supporting the conclusion of an adaptive significance of the observed morphological characteristics. Our results indicate that divergent natural selection resulting from foraging specialization is driving and/or maintaining the observed parallel morphological divergence. Whitefish in this study may represent an early stage of divergence towards the evolution of specialized morphs.
Analysis of the relationship between inundation frequency and wetland vegetation in Dongting Lake using remote sensing data
Authors: Deng Fan , Wang Xuelei , Cai Xiaobin , Li Enhua , Jiang Liuzhi , Li Hui , Yan Ranran 
Published: April 2013

ABSTRACTHydrological characteristics significantly drive the formation of and variations in wetland vegetation. Given increasing impact from human activities and climate change, the hydrological regime has become exceedingly unstable, thereby heavily affecting the distribution and dynamics of wetland vegetation. The relationship between inundation frequency – an important hydrological factor – and vegetation community distribution in Dongting Lake was analysed to depict how the hydrological regime determines the distribution of wetland vegetation cover. Wide tempo‐spatial scales were used to calculate the inundation frequency in the lake and to compare the distribution patterns of the communities. For the implementation of the aforementioned tasks, this study provides remote sensing‐ and geographical information system‐based methods. The responses of individual vegetation communities to inundation frequency differ depending on their specific physiological characteristics. Wood and reed communities are more suitable for regions with low inundation frequency, whereas grass and lake‐grass communities are more adaptable to areas of high inundation frequency. The variations in inundation frequency may explain the succession of vegetation communities, which occurs when inundation frequency decreases with increasing wood and reed communities. These results can serve as support for evaluating the impact of hydrological changes on the community structures and distributions of wetland vegetation. Copyright © 2013 John Wiley & Sons, Ltd.
Thermal and Photoinduced Electron Transfer in Directional Bis(terpyridine)ruthenium(II)–(Bipyridine)platinum(II) Complexes
Authors: Dietrich Jan , Wünsche von Leupoldt Anica , Grabolle Markus , Resch‐Genger Ute , Heinze Katja 
Published: April 2013

AbstractMetalloligands L1 and L2 consisting of directional bis(terpyridine)ruthenium(II) units and bipyridine moieties were constructed by amide formation. From these metalloligands two Ru–Pt heterobimetallic complexes 1 and 2 were derived by a building‐block method by means of platination with [PtCl2(dmso)2]. Both bimetallic complexes 1 and 2 feature metal‐to‐ligand charge transfer (MLCT) absorptions, and emission occurs at room temperature in fluid solution from 3MLCT(Ru) states in all cases. Energy transfer from platinum to ruthenium is observed in 2 but not in 1 (light harvesting). The one‐electron‐reduced species [1]– and [2]– were prepared by reduction of 1 and 2 with decamethylcobaltocene. EPR spectra and DFT calculations reveal that the spin density is localized at the tpy–CO/Ru (tpy = terpyridine) site in [1]–, whereas it is centered at bpy–CO/Pt (bpy = 2,2′‐bipyridine) in [2]–. Efficient photoinduced electron transfer from triethanolamine to 1 and 2 is feasible by excitation at 500 nm [MLCT(Ru)].
Chelate Structure of a Dirhodium–Amino Acid Complex Identified by Chiroptical and NMR Spectroscopy
Authors: Majer Zsuzsa , Szilvágyi Gábor , Benedek László , Csámpai Antal , Hollósi Miklós , Vass Elemér 
Published: April 2013

AbstractDinuclear rhodium complexes have attracted considerable attention as a result of their chemical and biological reactivity. We report herein the synthesis and structural elucidation by combined spectroscopic methods of a new rhodium complex containing N‐methyl‐D‐phenylalaninate (NMfO–) as a chiral ligand. It has been demonstrated that the structure of the chiral complex formed in water is independent of the ligand/metal molar ratio, the type of solvent, and reaction time, as shown by HPLC and ESI‐MS analyses. The steric structure of the isolated and identified [Rh2(OAc)2(OfMN)2] complex was determined by chiroptical (VCD, ECD) and NMR spectroscopy supported by DFT calculations. By this combined analysis, our studies have shown that the complex formed has two chiral ligands chelated through the O and N atoms of their carboxylate and sec‐amino groups, respectively, in the vicinity of the two bridging acetate ligands.
The Ant‐Pro Reverse‐Turn Motif. Structural Features and Conformational Characteristics
Authors: Thorat Vijaykumar H. , Ingole Tukaram S. , Vijayadas Kuruppanthara N. , Nair Roshna V. , Kale Sangram S. , Ramesh Veera V. E. , Davis Hilda C. , Prabhakaran Panchami , Gonnade Rajesh G. , Gawade Rupesh L. , Puranik Vedavati G. , Rajamohanan Pattuparambil R. , Sanjayan Gangadhar J. 
Published: April 2013

AbstractThis article details the characteristic conformational features of the Ant‐Pro reverse turn ― a folded pseudo β‐turn motif that displays a closed nine‐membered‐ring hydrogen‐bonded network involving just two amino acid residues, namely anthranilic acid (Ant; a constrained β‐amino acid), and proline (Pro; a constrained α‐amino acid). The results from the extensive investigation of ten crystal structures and their NMR conformations in the solution state provide a clear idea about the conformational characteristics of the Ant‐Pro reverse turn. The Ant and Pro residues, which form the turn segment, maintain a perfect antiperiplanar orientation throughout, leaving little possibility for the formation of the otherwise possible six‐membered hydrogen‐bonding that requires a coplanar disposition of the two amino acid residues, as clearly evident from investigation of several crystal structures. The closed hydrogen‐bonded network observed in the Ant‐Pro reverse turn motif, formed in the forward direction of the sequence (1→2 amino acid interactions) involving only two amino acid residues, is in stark contrast to the native β‐turns that involve four residues to form hydrogen‐bonded network featuring backward 1←4 amino acid interactions. The readily available two‐residue Ant‐Pro motif raises the possibility of a practical utility, particularly in the application of rigidifying flexible peptide backbones by inserting the robust Ant‐Pro reverse turn motifs into their backbone.
Foldamer Stability Coupled to Aggregation Propensity of Elongated Trp‐Cage Miniproteins
Authors: Farkas Viktor , Csordás Barbara , Hegyi Orsolya , Tóth Gábor K. , Perczel András 
Published: April 2013

AbstractHere we present folding‐associated aggregation propensity of three Trp‐cage foldamers: E0 (20 aa), E5 (25 aa) and E10 (30 aa), models of different sizes but comparable molecular properties. Electronic circular dichroism (ECD), vibrational circular dichroism (VCD) and FT‐IR spectroscopic measurements were used to monitor their concentration‐dependent, heat‐induced (5 °C → 65 °C) “α→β” fold transition. The ECD curves of E0 display an ensemble of highly dynamic structures. ECD of both E5 and E10 foldamers show the expected Trp‐cage fold, dominated by their α‐helical properties. No sign of β‐structures was revealed by ECD at any conditions (5 °C < T < 65 °C, 5 < pH < 7, c ≈ 30 μM) for any of these miniproteins. However, at higher concentration (c ≈ 1–30 mM) both VCD and FT‐IR spectral features of E5 as well as E10 resemble that of a β‐strand (ca. 1615 cm–1), accompanied with “free β‐edges”, or native β‐sheets (ca. 1635 cm–1). E5 at lower concentrations (c ≈ 1–3 mM), and E10 at higher concentration (c ≈ 30 mM) display the α→native‐β→β‐sheet folding transitions, monitored by the characteristic C=O vibrational normal mode frequency shift as follows: ca. 1650 cm–1 → ca. 1635 cm–1 → ca. 1615 cm–1, respectively. The latter folding path is irreversible. The shortest polypeptide E0 has an “unordered” fold, while E10 presents the most tightly packed Trp‐cage 3D‐structure. We have found that both high dynamicity and/or tight molecular core packing are different in nature, but common in efficacy in preventing the polypeptide backbone chain against self‐aggregation. However, E5 is intermediate in size and stability, and thus among these three polypeptides it is the quickest to aggregate. The present molecular triad, E0, E5 and E10, serves as a good example of larger globular proteins for which aggregation and amyloid fiber‐like nanoparticle formations are often associated with Alzheimer's, Creutzfeldt–Jakob, or prion diseases.