bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing aggressive intergroup action tendencies: Effects of intergroup contact via perceived intergroup threat
Authors: Schmid Katharina , Hewstone Miles , Küpper Beate , Zick Andreas , Tausch Nicole
Published: December 2013

Two studies tested the prediction that more positive intergroup contact would be associated with reduced aggressive intergroup action tendencies, an effect predicted to occur indirectly via reduced intergroup threat perceptions, and over and above well‐established effects of contact on intergroup attitudes. Study 1, using data based on a cross‐section of the general population of eight European countries (France, Germany, Hungary, Italy, the Netherlands, Poland, Portugal, and the UK; N = 7,042), examined this hypothesis in the context of aggressive action tendencies towards immigrants. Study 2, using longitudinal data obtained from a general population sample in Northern Ireland, considered effects on aggressive action tendencies between ethno‐religious groups in conflict. Both studies confirmed our predictions, showing that while perceived threat was associated with greater intergroup aggressive tendencies, positive intergroup contact was indirectly associated with reduced aggressive action tendencies, via reduced intergroup threat. Findings are discussed in terms of the theoretical contributions of this research for understanding the relationship between intergroup contact and intergroup aggression. Aggr. Behav. 40:250–262, 2014. © 2013 Wiley Periodicals, Inc.
Magnetic Assembly of Soft Robots with Hard Components
Authors: Kwok Sen W. , Morin Stephen A. , Mosadegh Bobak , So Ju‐Hee , Shepherd Robert F. , Martinez Ramses V. , Smith Barbara , Simeone Felice C. , Stokes Adam A. , Whitesides George M.
Published: December 2013

This paper describes the modular magnetic assembly of reconfigurable, pneumatically actuated robots composed of soft and hard components and materials. The soft components of these hybrid robots are actuators fabricated from silicone elastomers using soft lithography, and the hard components are acrylonitrile–butadiene–styrene (ABS) structures made using 3D printing. Neodymium–iron–boron (NdFeB) ring magnets are embedded in these components to make and maintain the connections between components. The reversibility of these magnetic connections allows the rapid reconfiguration of these robots using components made of different materials (soft and hard) that also have different sizes, structures, and functions; in addition, it accelerates the testing of new designs, the exploration of new capabilities, and the repair or replacement of damaged parts. This method of assembling soft actuators to build soft machines addresses some limitations associated with using soft lithography for the direct molding of complex 3D pneumatic networks. Combining the self‐aligning property of magnets with pneumatic control makes it possible for a teleoperator to modify the structures and capabilities of these robots readily in response to the requirements of different tasks.
A Stereospecific Synthesis and Unambiguous Assignment of the Absolute Configuration of (−)‐erythro‐Mefloquine Hydrochloride
Authors: Zhou Gang , Liu Xian , Liu Xueying , Nie Huifang , Zhang Shengyong , Chen Weiping
Published: December 2013

(−)‐erythro‐Mefloquine hydrochloride was synthesized stereospecifically from commercially available (S)‐(−)‐1‐Boc‐2‐piperidinecarboxylic acid in four steps without disturbing the chiral center, and the absolute configuration of (−)‐erythro‐mefloquine hydrochloride was unambiguously determined as (11R,12S). (11S,12R)‐(+)‐erythro‐Mefloquine hydrochloride was synthesized utilizing [(S,S)‐TsDpen]Ru(p‐cymene)Cl complexes‐catalyzed enantioselective transfer hydrogenation of pyridyl ketone 7 as the key step, and the sense of asymmetric induction of 2‐pyridyl ketone 7 is opposite to that of normal ketones in the transfer hydrogenation. Our results confirm the correctness of the determination of the absolute configuration by three physical chemistry methods, and, unbelievably, the erroneous assignments by all previous five asymmetric syntheses.

magnified image
Efficient Synthesis of Dibenzoxaborininols from Diaryl Ethers and Their Application to Dibenzofuran Synthesis
Authors: Niu Liting , Yang Haijun , Jiang Yuyang , Fu Hua
Published: December 2013

A convenient and efficient method for the borylation of diaryl ethers leading to dibenzoxaborininols and the synthesis of dibenzofuran derivatives has been developed. The borylation involves the sequential three‐step process: lithiation, borylation and hydrolysis. The synthesized dibenzoxaborininols could be readily transformed into dibenzofuran derivatives in good to excellent yields under palladium catalysis in the presence of iodine, and this is the first example for the formation of an aryl CC bond from diarylborinic acids.

magnified image
Palladium Nanoparticles in Glycerol: A Versatile Catalytic System for CX Bond Formation and Hydrogenation Processes
Authors: Chahdoura Faouzi , Pradel Christian , Gómez Montserrat
Published: December 2013

Palladium nanoparticles stabilised by tris(3‐sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in CX bond formation processes (X=C, N, P, S) and CC multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as‐prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular‐ and surface‐like behaviour), has allowed attractive applications in one‐pot multi‐step transformations catalysed by palladium, such as CC coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor.

magnified image
Oxidative Heck Coupling of Allylic Amines with 2,2,6,6‐Tetramethylpiperidine‐N‐oxyl (TEMPO) as Oxidant for the Preparation of Tetrasubstituted Alkenes
Authors: He Zhiheng , Wibbeling Birgit , Studer Armido
Published: December 2013

The paper describes the oxidative Heck arylation of various allylic amines using arylboronic acids for the preparation of tetrasubstituted alkenes. As oxidant the commercially available 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) is used and coupling reactions occur under very mild conditions at room temperature. The densely substituted alkenes are formed in good to excellent yields with complete control of the diastereoselectivity. Substrate scope with respect to the allylic amine and the arylboronic acid is investigated.

magnified image
Highly Efficient Catalytic Dimerization of StyrenesviaCationic Palladium(II) Complexes
Authors: Choi Ji Hye , Kwon Jae Kwan , RajanBabu T. V. , Lim Hwan Jung
Published: December 2013

A highly efficient head‐to‐tail dimerization of a styrene was developed using a cationic palladium(II)‐catalyzed selective CC bond forming reaction. The complex [AllylPd(PPh3)]+OTf−, which is believed to generate ‘palladium hydride’ (PdH), catalyzed the dimerization of various styrenes in excellent yields as single isomers. This Pd(II)‐catalyzed reaction provides a new economical CC bond forming method.

magnified image
Die Elektrochemie des Sauerstoffs als Meilenstein für eine nachhaltige Energieumwandlung
Authors: Katsounaros Ioannis , Cherevko Serhiy , Zeradjanin Aleksandar R. , Mayrhofer Karl J. J.
Published: December 2013

Elektrochemie wird eine entscheidende Rolle bei der Einführung von nachhaltigen Lösungen zur Energieversorgung spielen, besonders im Bereich der Umwandlung und Speicherung von elektrischer in chemische Energie in Elektrolysezellen sowie bei der Rückumwandlung und Verwendung der gespeicherten Energie in galvanischen Zellen. Die gemeinsame Herausforderung für beide Prozesse ist die Entwicklung von – bevorzugt leicht verfügbaren – nanostrukturierten Materialien, die diese elektrochemischen Reaktionen mit einem hohen Umsatz und über einen genügend langen Zeitraum katalysieren können. Für die gezielte Entwicklung von Materialien, die diese Voraussetzungen erfüllen, ist es notwendig, die zugrunde liegenden Prozesse und Mechanismen, die unter realen Bedingungen auftreten, vollständig zu verstehen. Eine vielversprechende Strategie, um dieses Verständnis zu erreichen, besteht in der Untersuchung des Einflusses der Materialeigenschaften auf die Aktivität oder Selektivität der Reaktion und die Stabilität unter Anwendungsbedingungen sowie in der Verwendung von komplementären In‐situ‐Techniken zur Untersuchung der Katalysatorstruktur und ‐zusammensetung.
Activation and Retention: A Magnetic Resonance Probe for the Detection of Acute Thrombosis
Authors: Loving Galen S. , Caravan Peter
Published: December 2013

Blood‐clot formation that results in the complete occlusion of a blood vessel (thrombosis) often leads to serious life‐threatening events, such as strokes and heart attacks. As the composition of a thrombus changes as it matures, new imaging methods that are capable of distinguishing new clots from old clots may yield important diagnostic and prognostic information. To address this need, an activatable magnetic resonance (MR) probe that is responsive to a key biochemical process associated with recently formed clots has been developed.
Oxygen Electrochemistry as a Cornerstone for Sustainable Energy Conversion
Authors: Katsounaros Ioannis , Cherevko Serhiy , Zeradjanin Aleksandar R. , Mayrhofer Karl J. J.
Published: December 2013

Electrochemistry will play a vital role in creating sustainable energy solutions in the future, particularly for the conversion and storage of electrical into chemical energy in electrolysis cells, and the reverse conversion and utilization of the stored energy in galvanic cells. The common challenge in both processes is the development of—preferably abundant—nanostructured materials that can catalyze the electrochemical reactions of interest with a high rate over a sufficiently long period of time. An overall understanding of the related processes and mechanisms occurring under the operation conditions is a necessity for the rational design of materials that meet these requirements. A promising strategy to develop such an understanding is the investigation of the impact of material properties on reaction activity/selectivity and on catalyst stability under the conditions of operation, as well as the application of complementary in situ techniques for the investigation of catalyst structure and composition.
Vinyl polymerizations of norbornene catalyzed by nickel complexes with acetoacetamide ligands
Authors: Feng Qian , Chen Dajun , Feng Danyang , Jiao Libin , Peng Zhigang , Pei Lixia
Published: December 2013

On the basis of a remote effect, a series of acetoacetamide ligands and corresponding nickel complexes N‐(R‐phenyl) acetoacetamide Ni(CH2Ph) (PMe3) (R = H, 1; R = 2‐methyl, 2; R = 2,6‐dimethyl, 3; R = 2,6‐diisopropyl, 4; R = 4‐NO2, 5) were synthesized and characterized. The solid structure of complex 3 was confirmed by X‐ray single‐crystal analysis to be of cis form. 1H and 31P NMR spectroscopy confirmed that cis and trans isomers of nickel complexes were present in solution. Norbornene polymerizations with acetoacetamide nickel complexes activated with modified methylaluminoxane (MMAO) were investigated in detail. Remote steric and electronic effects of acetoacetamide ligand on catalytic activity and molecular weight of polynorbornenes (PNBs) were observed. Characterizations of the obtained PNBs show that the obtained polymer products are non‐crystalline vinylic‐addition polynorbornenes. Copyright © 2013 John Wiley & Sons, Ltd.
Hydrodynamics of binary mixtures in a tapered gas–solid fluidized bed
Authors: Ren Gang , Pei Pei , Zhang Kai , Wen Dongsheng
Published: December 2013

Tapered fluidized‐bed reactors are suggested for biomass catalytic pyrolysis in this work. Both experiments and computational fluid dynamics simulations on hydrodynamics are conducted in a two‐dimensional bed with an overall taper angle of 43.8° by using rapeseed as biomass and resin as substitutable catalyst. The results show that the jet penetration depth decreases with increasing initial bed height or decreasing jet gas velocity. However, the jet penetration depth displays a first‐increase and then‐decrease tendency with increasing resin fraction or annular gas velocity. A comparison of hydrodynamics between measured and simulated data, including the stochastic nature of the jets, identifies that the simple non‐viscous two‐fluid model can be used to predict the jet behaviors of both mono‐particle system and well‐mixed biomass mixtures. The results provide fundamental information for the design and scale‐up of tapered fluidized‐bed reactors for solid biomass catalytic pyrolysis. Copyright © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
Diels–Alder‐based crosslinked self‐healing polyurethane/urea from polymeric methylene diphenyl diisocyanate
Authors: Du Pengfei , Wu Meiyin , Liu Xuanxuan , Zheng Zhen , Wang Xinling , Joncheray Thomas , Zhang Yuefan
Published: December 2013

Crosslinked self‐healing polyurethane/urea based on a Diels–Alder reaction (C‐PMPU–DA) was synthesized from a multiple‐furan monomer and a commercial bismaleimide. The multiple‐furan monomer (PMPU–furan) was obtained from a functionalized prepolymer (polymeric MDI: PBA‐2000 = 2:1) by furfuryl amine. The structures of both the PMPU–furan and C‐PMPU–DA were characterized by attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and 1H‐NMR. The Diels–Alder bonds enabled C‐PMPU–DA thermal reversibility, which was investigated by ATR–FTIR spectroscopy, 1H‐NMR, gel–solution–gel experiments, and viscosity tests. Meanwhile, the self‐healing properties of C‐PMPU–DA were also investigated by the recovery of the mechanical properties. The results showed that C‐PMPU–DA exhibited good thermal reversibility and self‐healing properties. C‐PMPU–DA exhibited thermosetting properties at room temperature, although it exhibited thermoplastic properties at higher temperatures and may find applications in self‐healing materials, recyclable materials, or removable materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40234.
REVISITING RUBISCO AS A PROTEIN SUBSTRATE FOR INSECT MIDGUT PROTEASES
Authors: Bhardwaj Usha , Bhardwaj Amit , Kumar Rakesh , Leelavathi Sadhu , Reddy Vanga Siva , Mazumdar‐Leighton Sudeshna
Published: December 2013

Gene fragments encoding the large subunit (LS) of Rubisco (RBCL) were cloned from various species of host plants of phytophagous Lepidoptera and expressed as recombinant proteins in Escherichia coli. Recombinant RBCLs were compared among each other along with casein and native Rubisco as proteinaceous substrates for measuring total midgut protease activities of fourth instar larvae of Helicoverpa armigera feeding on casein, Pieris brassicae feeding on cauliflower, and Antheraea assamensis feeding on Litsea monopetala and Persea bombycina. Cognate rRBCL (from the pertinent host plant species) substrates performed similar to noncognate rRBCL reflecting the conserved nature of encoding genes and the versatile use of these recombinant proteins. Casein and recombinant RBCL generally outperformed native Rubisco as substrates, except where inclusion of a reducing agent in the enzyme assay likely unfolded the plant proteins. Levels of total midgut protease activities detected in A. assamensis larvae feeding on two primary host species were similar, suggesting that the suite(s) of digestive enzymes in these insects could hydrolyze a plant protein efficiently. Protease activities detected in the presence of protease inhibitors and the reducing agent dithiothreitol (DTT) suggested that recombinant RBCL was a suitable protein substrate for studying insect proteases using in vitro enzyme assays and substrate zymography.
Simulation of aerosol effects on orographic clouds and precipitation using WRF model with a detailed bin microphysics scheme
Authors: Xiao Hui , Yin Yan , Jin Lianji , Chen Qian , Chen Jinghua
Published: December 2013

The effects on orographic clouds and precipitation of aerosol loading have been investigated by simulating an idealized mixed‐phase orographic cloud using the Weather Research Forecast (WRF) mesoscale model coupled with a detailed bin microphysics scheme. The results show that the total precipitation amount is reduced by 23.4% with increasing aerosol loading on the orographic clouds. Moreover, increasing aerosol loading will increase the number concentration of cloud droplets in small size range (<19.84 µm in diameter) and lead to a decrease in the peak diameter from 12.5 to 9.92 µm.
The ability of stratospheric climate engineering in stabilizing global mean temperatures and an assessment of possible side effects
Authors: Izrael Yu. A. , Volodin E. M. , Kostrykin S. V. , Revokatova A. P. , Ryaboshapko A. G.
Published: December 2013

A coupled atmosphere–ocean general circulation model is used to assess the ability of stratospheric climate engineering (CE) in stabilizing global mean temperatures at the threshold level +2 °C compared to pre‐industrial conditions. CE impact by solar radiation management (SRM) method is applied, when temperature threshold (+2 °C) is reached. Injection intensity is adjusted by the model so that calculated global temperature is remained close to the threshold value. We demonstrate that CE temperature stabilization during the 21st century is possible within the range of +2 ± 0.11 °C. Changes of precipitation intensity as well as effect of sharp termination of CE are investigated.
Atypical teratoid rhabdoid tumor: improved long‐term survival with an intensive multimodal therapy and delayed radiotherapy. The Medical University of Vienna Experience 1992–2012
Authors: Slavc Irene , Chocholous Monika , Leiss Ulrike , Haberler Christine , Peyrl Andreas , Azizi Amedeo A. , Dieckmann Karin , Woehrer Adelheid , Peters Christina , Widhalm Georg , Dorfer Christian , Czech Thomas
Published: December 2013

Atypical teratoid rhabdoid tumors (ATRTs) are recently defined highly aggressive embryonal central nervous system tumors with a poor prognosis and no definitive guidelines for treatment. We report on the importance of an initial correct diagnosis and disease‐specific therapy on outcome in 22 consecutive patients and propose a new treatment strategy. From 1992 to 2012, nine patients initially diagnosed correctly as ATRT (cohort A, median age 24 months) were treated according to an intensive multimodal regimen (MUV‐ATRT) consisting of three 9‐week courses of a dose‐dense regimen including doxorubicin, cyclophosphamide, vincristine, ifosfamide, cisplatin, etoposide, and methotrexate augmented with intrathecal therapy, followed by high‐dose chemotherapy (HDCT) and completed with local radiotherapy. Thirteen patients were treated differently (cohort B, median age 30 months) most of whom according to protocols in use for their respective diagnoses. As of July 2013, 5‐year overall survival (OS) and event‐free survival (EFS) for all 22 consecutive patients was 56.3 ± 11.3% and 52.9 ± 11.0%, respectively. For MUV‐ATRT regimen‐treated patients (cohort A) 5‐year OS was 100% and EFS was 88.9 ± 10.5%. For patients treated differently (cohort B) 5‐year OS and EFS were 28.8 ± 13.1%. All nine MUV‐ATRT regimen‐treated patients are alive for a median of 76 months (range: 16–197), eight in first complete remission. Our results compare favorably to previously published data. The drug combination and sequence used in the proposed MUV‐ATRT regimen appear to be efficacious in preventing early relapses also in young children with M1–M3 stage disease allowing postponement of radiotherapy until after HDCT.
Mitsunobu Reactions of 5‐Fluorouridine with the Terpenols Phytol and Nerol: DNA Building Blocks for a Biomimetic Lipophilization of Nucleic Acids
Authors: Malecki Edith , Knies Christine , Werz Emma , Rosemeyer Helmut
Published: December 2013

The cancerostatic 5‐fluorouridine (5‐FUrd; 1) was sequentially sugar‐protected by introduction of a 2′,3′‐O‐heptylidene ketal group (→2), followed by 5′‐O‐monomethoxytritylation (→3). This fully protected derivative was submitted to Mitsunobu reactions with either phytol ((Z and E)‐isomer) or nerol ((Z)‐isomer) to yield the nucleoterpenes 4a and 4b. Both were 5′‐O‐deprotected with 2% Cl2CHCOOH in CH2Cl2 to yield compounds 5a and 5b, respectively. These were converted to the 5′‐O‐cyanoethyl phosphoramidites 6a and 6b, respectively. Moreover, the 2′,3′‐O‐(1‐nonyldecylidene) derivative, 7a, of 5‐fluorouridine was resynthesized and labelled at C(5′) with an Eterneon‐480 fluorophor® (→7b). The resulting nucleolipid was studied with respect to its incorporation in an artificial bilayer, as well as to its aggregate formation. Additionally, two oligonucleotides carrying terminal phytol‐alkylated 5‐fluorouridine tags were prepared, one of which was studied concerning its incorporation in an artificial lipid bilayer.
Catheter approach to redirect hepatic venous return for treatment of unilateral pulmonary arteriovenous malformations after fontan
Authors: Dori Yoav , Sathanandam Shyam , Glatz Andrew C. , Gillespie Matthew J. , Rome Jonathan J.
Published: December 2013

Objectives

The goal of this report is to describe a percutaneous approach to rerouting hepatic venous return in patients who developed progressive cyanosis due to unilateral pulmonary arteriovenous malformations (PAVM) after the total cavopulmonary connection (TCPC) operation.

Background

Unilateral PAVM can develop in patients after TCPC operation when there is unequal distribution of hepatic venous return between the two lungs. This often results in progressive cyanosis and the need for surgical re‐intervention. A percutaneous based approach for rerouting hepatic venous return has never been described.

Methods

We retrospectively reviewed the clinical data on four patients who underwent percutaneous rerouting procedures. One patient with a misaligned TCPC underwent realignment of the circuit with a bare metal stent. In three patients a combination of bare metal and covered stents were needed to achieve the desired results.

Results

The rerouting procedures were successful in all patients with significant improvement in oxygen saturation from a median of 75% (range 55–80%) to a median of 90% (range 84–92%) (P = 0.02). There were no recorded short term or intermediate term complications with maximum follow‐up time of 43 months.

Conclusions

Percutaneous rerouting of hepatic venous flow is feasible and should be considered when a surgical approach is not possible; this strategy may serve as a viable alternative to complex operative approaches in select cases. Furthermore studies are needed to determine the long‐term efficacy of this procedure. © 2013 Wiley Periodicals, Inc.
Frequency and outcomes of aortocoronary dissection during percutaneous coronary intervention of chronic total occlusions
Authors: Shorrock Deborah , Michael Tesfaldet T. , Patel Vishal , Kotsia Anna , Rangan Bavana V. , Abdullah Shuaib A. , Grodin Jerrold M. , Banerjee Avantika , Brilakis Emmanouil S.
Published: December 2013

Background

Aortocoronary dissection can complicate percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs).

Methods

We retrospectively examined the frequency and outcomes of aortocoronary dissection among 336 consecutive CTO PCIs performed at our institution between 2005 and 2012 and performed a systematic review of the published literature.

Results

Aortocoronary dissection occurred in six patients (1.8%, 95% confidence intervals 0.7%, 3.8%). All aortocoronary dissections occurred in the right coronary artery (CTO target vessel in five patients and donor vessel in one patient). The baseline clinical characteristics of patients with and without aortocoronary dissection were similar. Compared to patients without, those with aortocoronary dissection were more likely to undergo crossing attempts using the retrograde approach (25% vs. 67%, P = 0.036) and experience a major complication (2.4% vs. 33.3%, P = 0.008). Technical and procedural success rates were similar in both groups. Of the six patients with aortocoronary dissection one underwent emergency coronary bypass graft surgery (CABG), four were treated with ostial stenting, and one was treated conservatively without subsequent adverse clinical outcomes. Systematic literature review provided 107 published cases of aortocoronary dissection during PCI, that occurred mainly in the right coronary artery (74.8%) and were treated with stenting (49.5%), emergency CABG (29%), or conservatively (21.5%).

Conclusions

Aortocoronary dissection is an infrequent complication of CTO PCI and although it can be treated with stents in most patients, it may infrequently require emergency CABG. © 2013 Wiley Periodicals, Inc.
Pillared Cobalt–Amino Acid Framework Catalysis for Styrene Carbonate Synthesis from CO2 and Epoxide by Metal–Sulfonate–Halide Synergism
Authors: Kathalikkattil Amal Cherian , Roshan Roshith , Tharun Jose , Soek Han‐Geul , Ryu Hyeong‐Seok , Park Dae‐Won
Published: December 2013

The sulfonate anion is proposed as a remarkable partaker in catalyzing epoxide–CO2 cycloaddition for cyclic carbonate synthesis. The role is illustrated by the concerted action of a sulfonate‐rich cobalt–amino acid framework catalyst [{Co(4,4′‐bipy)(L‐cys)(H2O)}⋅H2O]n (2 D‐CCB) and a quaternary ammonium bromide co‐catalyst in synthesizing styrene carbonate (SC) at a turnover number of 228. SC yield at atmospheric pressure is presumed to result from the activation of CO2 by the sulfonate group. The involvement of SO3− anions as basic sites in 2 D‐CCB is ascertained from the initial rate (r0) for catalyzing Knoevenagel condensation reactions and by using CO2 temperature programmed desorption. Microwave pulses are used for synthesizing 2 D‐CCB at a rate that is 288‐fold faster than conventionally employed solvothermal methods. Unambiguous evidence for the pulsating role‐play of sulfonate groups in 2 D‐CCB is perceived by comparing the activity of an analogous metal organic framework (3 D‐CCB) in which the sulfonate oxyanions are jammed by coordination with cobalt. 2 D‐CCB is analyzed for heterogeneity, and reused four times.
Enantioselective Rearrangement Coupled with Water Addition: Direct Synthesis of Enantiomerically Pure Saturated Carboxylic Acids from α,β‐Unsaturated Aldehydes
Authors: Winkler Till , Gröger Harald , Hummel Werner
Published: December 2013

A novel type of organic synthesis enabling a direct one‐pot transformation of α,β‐unsaturated aldehydes into saturated carboxylic acids is described. As sole reagent water is required, which is integrated completely in the product. This tandem process proceeds under perfect atom economy, and consists of two coupled redox biotransformations without the need of external co‐substrates for cofactor regeneration. The initial reduction of the CC double bond of an α,β‐unsaturated aldehyde is catalyzed by an NADPH‐dependent ene reductase, leading to the formation of the saturated aldehyde and NADP+. The aldehyde intermediate is then oxidized to the corresponding carboxylic acid, thus regenerating NADPH for the next catalytic cycle. When using prochiral α,β‐unsaturated aldehydes as substrates the corresponding carboxylic acids are formed enantioselectively with up to >99 % ee as demonstrated, e.g., for the transformation of citral to (S)‐citronellic acid.
Quinonediimine‐Induced Oxidative Coupling of Organomagnesium Reagents
Authors: Amaya Toru , Suzuki Riyo , Hirao Toshikazu
Published: December 2013

N,N′‐Diphenyl‐p‐benzoquinonediimine, a redox‐active unit of polyaniline, efficiently induced the oxidative homocoupling of various aryl‐ and vinylmagnesium reagents in suppressing the side reactions, such as 1,2‐ or 1,4‐addition reaction.
Dimers of N‐Heterocyclic Carbene Copper, Silver, and Gold Halides: Probing Metallophilic Interactions through Electron Density Based Concepts
Authors: Pinter Balazs , Broeckaert Lies , Turek Jan , Růžička Aleš , De Proft Frank
Published: December 2013

Homobimetallic metallophilic interactions between copper, silver, and gold‐based [(NHC)MX]‐type complexes (NHC=N‐heterocyclic carbene, i.e, 1,3,4‐trimethyl‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ylidene; X=F, Cl, Br, I) were investigated by means of ab initio interaction energies, Ziegler–Rauk‐type energy‐decomposition analysis, the natural orbital for chemical valence (NOCV) framework, and the noncovalent interaction (NCI) index. It was found that the dimers of these complexes predominantly adopt a head‐to‐tail arrangement with typical M⋅⋅⋅M distance of 3.04–3.64 Å, in good agreement with the experimental X‐ray structure determined for [{(NHC)AuCl}2], which has an Au⋅⋅⋅Au distance of 3.33 Å. The interaction energies between silver‐ and gold‐based monomers are calculated to be about −25 kcal mol−1, whereas that for the Cu congener is significantly lower (−19.7 kcal mol−1). With the inclusion of thermal and solvent contributions, both of which are destabilizing, by about 15 and 8 kcal mol−1, respectively, an equilibrium process is predicted for the formation of dimer complexes. Energy‐decomposition analysis revealed a dominant electrostatic contribution to the interaction energy, besides significantly stabilizing dispersion and orbital interactions. This electrostatic contribution is rationalized by NHC(δ+)⋅⋅⋅halogen(δ−) interactions between monomers, as demonstrated by electrostatic potentials and derived charges. The dominant NOCV orbital indicates weakening of the π backdonation in the monomers on dimer formation, whereas the second most dominant NOCV represents an electron‐density deformation according to the formation of a very weak M⋅⋅⋅M bond. One of the characteristic signals found in the reduced density gradient versus electron density diagram corresponds to the noncovalent interactions between the metal centers of the monomers in the NCI plots, which is the manifestation of metallophilic interaction.
Reactivity of Oxygen Radical Anions Bound to Scandia Nanoparticles in the Gas Phase: CH Bond Activation
Authors: Tian Li‐Hua , Meng Jing‐Heng , Wu Xiao‐Nan , Zhao Yan‐Xia , Ding Xun‐Lei , He Sheng‐Gui , Ma Tong‐Mei
Published: December 2013

The activation of CH bonds in alkanes is currently a hot research topic in chemistry. The atomic oxygen radical anion (O−.) is an important species in CH activation. The mechanistic details of CH activation by O−. radicals can be well understood by studying the reactions between O−. containing transition metal oxide clusters and alkanes. Here the reactivity of scandium oxide cluster anions toward n‐butane was studied by using a high‐resolution time‐of‐flight mass spectrometer coupled with a fast flow reactor. Hydrogen atom abstraction (HAA) from n‐butane by (Sc2O3)NO− (N=1–18) clusters was observed. The reactivity of (Sc2O3)NO− (N=1–18) clusters is significantly sizedependent and the highest reactivity was observed for N=4 (Sc8O13−) and 12 (Sc24O37−). Larger (Sc2O3)NO− clusters generally have higher reactivity than the smaller ones. Density functional theory calculations were performed to interpret the reactivity of (Sc2O3)NO− (N=1–5) clusters, which were found to contain the O−. radicals as the active sites. The local charge environment around the O−. radicals was demonstrated to control the experimentally observed size‐dependent reactivity. This work is among the first to report HAA reactivity of cluster anions with dimensions up to nanosize toward alkane molecules. The anionic O−. containing scandium oxide clusters are found to be more reactive than the corresponding cationic ones in the CH bond activation.
Ethane‐Bridged Periodic Mesoporous Organosilicas Functionalized with High Loadings of Carboxylic Acid Groups: Synthesis, Bifunctionalization, and Fabrication of Metal Nanoparticles
Authors: Deka Juti Rani , Kao Hsien‐Ming , Huang Shu‐Ying , Chang Wei‐Chieh , Ting Chun‐Chiang , Rath Purna Chandra , Chen Ching‐Shiun
Published: December 2013

Well‐ordered periodic mesoporous organosilicas (PMOs) functionalized with high contents of carboxylic acid (COOH) groups, up to 85 mol % based on silica, were synthesized by co‐condensation of 1,2‐bis(triethoxysilyl)ethane (BTEE) and carboxyethylsilanetriol sodium salt (CES) under acidic conditions by using alkyl poly(oxyethylene) surfactant Brij 76 as a structure‐directing agent. A variety of techniques including powder X‐ray diffraction (XRD), nitrogen adsorption/desorption, Fourier‐transformed infrared (FTIR), transmission electron microscopy (TEM), 13C‐ and 29Si solid‐state nuclear magnetic resonance (NMR) were used to characterize the products. The materials thus obtained were used as an effective support to synthesize metal nanoparticles (Ag and Pt) within the channel of 2D hexagonal mesostructure of PMOs. The size and distribution of the nanoparticles were observed to be highly dependent on the interaction between the carboxylic acid functionalized group and the metal precursors. The size of Pt nanoparticles reduced from 3.6 to 2.5 nm and that of Ag nanoparticles reduced from 5.3 to 3.4 nm with the increase in the COOH loading from 10 to 50 %.
Theoretical and Structural Analysis of Long CC Bonds in the Adducts of Polycyanoethylene and Anthracene Derivatives and Their Connection to the Reversibility of Diels–Alder Reactions
Authors: Hirsch Anna K. H. , Reutenauer Philippe , Le Moignan Marc , Ulrich Sébastien , Boul Peter J. , Harrowfield Jack M. , Jarowski Peter D. , Lehn Jean‐Marie
Published: December 2013

X‐ray structure determinations on four Diels–Alder adducts derived from the reactions of cyano‐ and ester‐substituted alkenes with anthracene and 9,10‐dimethylanthracene have shown the bonds formed in the adduction to be particularly long. Their lengths range from 1.58 to 1.62 Å, some of the longest known for Diels–Alder adducts. Formation of the four adducts is detectably reversible at ambient temperature and is associated with free energies of reaction ranging from −2.5 to −40.6 kJ mol−1. The solution equilibria have been experimentally characterised by NMR spectroscopy. Density‐functional‐theory calculations at the MPW1K/6‐31+G(d,p) level with PCM solvation agree with experiment with average errors of 6 kJ mol−1 in free energies of reaction and structural agreement in adduct bond lengths of 0.013 Å. To understand more fully the cause of the reversibility and its relationship to the long adduct bond lengths, natural‐bond‐orbital (NBO) analysis was applied to quantify donor–acceptor interactions within the molecules. Both electron donation into the σ*‐anti‐bonding orbital of the adduct bond and electron withdrawal from the σ‐bonding orbital are found to be responsible for this bond elongation.
Nanosheet‐Stacked Chiral Silica Transcribed from Metal Ion‐ and pH‐Tuned Supramolecular Crystalline Complexes of Polyamine‐D‐Glucarate
Authors: Matsukizono Hiroyuki , Murada Hiroki , Jin Ren‐Hua
Published: December 2013

D‐Glucaric acid (D‐Glc) associates with linear poly(ethyleneimine) (PEI) through hydrogen bonding and electrostatic interactions in aqueous media to form nanostructured crystalline PEI/D‐Glc/H2O complexes with PEI/D‐Glc/H2O ratios of 2:1:2. These complexes can serve as templates for silica depositions from hydrolytic condensation of tetramethoxysilane to guide morphologically duplicated silica under very mild conditions. Their microscale morphologies are tunable by use of the crystalline complexes regulated in the different pH of the PEI/D‐Glc solutions. It was also found that some metal ions added in the PEI/D‐Glc complexation process could have a synergistic effect under a certain pH regimes, bringing about remarkable changes in the hierarchy of the resulting complexes. Especially, the complexes formed through fine‐tuning of the complexation conditions could direct torsionally stacked silica nanosheets, in which the nanosheets are composed of orderly‐bundled nanofibrils. Final elimination of organic components of the templates afforded chiral inorganic silica while retaining the morphologically higher‐order structures. The chirality of the silica, which was obtained after calcination at 600 °C, was characterized by means of diffused reflectance circular dichroism (DRCD) spectroscopy with a remote confirmation of the appearance of induced‐CD (ICD) signals of achiral or racemic chromophores covalently linked on the silica frames. Interestingly, the shapes and signs of these ICD signals are dramatically changed depending on the pH‐tuned templates used in silicification and are strongly correlated to that of the CD signals of the complex templates, indicating that the chiral transcription proceeds accurately with imprinting the higher‐order chirality of the complexes on the morphologically structured silica networks.
Polar Red‐Emitting Rhodamine Dyes with Reactive Groups: Synthesis, Photophysical Properties, and Two‐Color STED Nanoscopy Applications
Authors: Kolmakov Kirill , Wurm Christian A. , Meineke Dirk N. H. , Göttfert Fabian , Boyarskiy Vadim P. , Belov Vladimir N. , Hell Stefan W.
Published: December 2013

The synthesis, reactivity, and photophysical properties of new rhodamines with intense red fluorescence, two polar residues (hydroxyls, primary phosphates, or sulfonic acid groups), and improved hydrolytic stability of the amino‐reactive sites (NHS esters or mixed N‐succinimidyl carbonates) are reported. All fluorophores contain an N‐alkyl‐1,2‐dihydro‐2,2,4‐trimethylquinoline fragment, and most of them bear a fully substituted tetrafluoro phenyl ring with a secondary carboxamide group. The absorption and emission maxima in water are in the range of 635–639 and 655–659 nm, respectively. A vastly simplified approach to red‐emitting rhodamines with two phosphate groups that are compatible with diverse functional linkers was developed. As an example, a phosphorylated dye with an azide residue was prepared and was used in a click reaction with a strained alkyne bearing an N‐hydroxysuccinimid (NHS) ester group. This method bypasses the undesired activation of phosphate groups, and gives an amphiphilic amino‐reactive dye, the solubility and distribution of which between aqueous and organic phases can be controlled by varying the pH. The presence of two hydroxyl groups and a phenyl ring with two carboxyl residues in the dyes with another substitution pattern is sufficient for providing the hydrophilic properties. Selective formation of a mono‐N‐hydroxysuccinimidyl ester from 5‐carboxy isomer of this rhodamine is reported. The fluorescence quantum yields varied from 58 to 92 % for free fluorophores, and amounted to 18–64 % for antibody conjugates in aqueous buffers. The brightness and photostability of these fluorophores facilitated two‐color stimulated emission depletion (STED) fluorescence nanoscopy of biological samples with high contrast and minimal background. Selecting a pair of fluorophores with absorption/emission bands at 579/609 and 635/655 nm enabled two‐color channels with low cross‐talk and negligible background at approximately 40 nm resolution.
Stereoselective Synthesis of Fluoroalkenoates and Fluorinated Isoxazolidinones: N‐Substituents Governing the Dual Reactivity of Nitrones
Authors: Prakash G. K. Surya , Zhang Zhe , Wang Fang , Rahm Martin , Ni Chuanfa , Iuliucci Marc , Haiges Ralf , Olah George A.
Published: December 2013

α‐Fluoroalkenoates and 4‐fluoro‐5‐isoxazolidinones are of vast interest due to their potential biological applications. We now demonstrate the syntheses of (E)‐α‐fluoroalkenoates and 4‐fluoro‐5‐isoxazolidinones by the reactions between nitrones and α‐fluoro‐α‐bromoacetate. By altering N‐substituents in nitrones, (E)‐α‐fluoroalkenoates and 4‐fluoro‐5‐isoxazolidinones can be achieved, respectively, with high chemo‐ and stereoselectivities. Experimental and computational studies have been conducted to elucidate the reaction mechanisms. Linear free energy relationship studies further revealed that the N‐substituent effects are primarily of electronic origin.
Reactivity of TpMe2‐Supported Yttrium Alkyl Complexes toward Aromatic N‐Heterocycles: Ring‐Opening or CC Bond Formation Directed by CH Activation
Authors: Yi Weiyin , Zhang Jie , Huang Shujian , Weng Linhong , Zhou Xigeng
Published: December 2013

Unusual chemical transformations such as three‐component combination and ring‐opening of N‐heterocycles or formation of a carbon–carbon double bond through multiple C–H activation were observed in the reactions of TpMe2‐supported yttrium alkyl complexes with aromatic N‐heterocycles. The scorpionate‐anchored yttrium dialkyl complex [TpMe2Y(CH2Ph)2(THF)] reacted with 1‐methylimidazole in 1:2 molar ratio to give a rare hexanuclear 24‐membered rare‐earth metallomacrocyclic compound [TpMe2Y(μ‐N,C‐Im)(η2‐N,C‐Im)]6 (1; Im=1‐methylimidazolyl) through two kinds of C–H activations at the C2‐ and C5‐positions of the imidazole ring. However, [TpMe2Y(CH2Ph)2(THF)] reacted with two equivalents of 1‐methylbenzimidazole to afford a C–C coupling/ring‐opening/C–C coupling product [TpMe2Y{η3‐(N,N,N)‐N(CH3)C6H4NHCHC(Ph)CN(CH3)C6H4NH}] (2). Further investigations indicated that [TpMe2Y(CH2Ph)2(THF)] reacted with benzothiazole in 1:1 or 1:2 molar ratio to produce a C–C coupling/ring‐opening product {(TpMe2)Y[μ‐η2:η1‐SC6H4N(CHCHPh)](THF)}2 (3). Moreover, the mixed TpMe2/Cp yttrium monoalkyl complex [(TpMe2)CpYCH2Ph(THF)] reacted with two equivalents of 1‐methylimidazole in THF at room temperature to afford a trinuclear yttrium complex [TpMe2CpY(μ‐N,C‐Im)]3 (5), whereas when the above reaction was carried out at 55 °C for two days, two structurally characterized metal complexes [TpMe2Y(Im‐TpMe2)] (7; Im‐TpMe2=1‐methyl‐imidazolyl‐TpMe2) and [Cp3Y(HIm)] (8; HIm=1‐methylimidazole) were obtained in 26 and 17 % isolated yields, respectively, accompanied by some unidentified materials. The formation of 7 reveals an uncommon example of construction of a CC bond through multiple C–H activations.
Copper–Boxmi Complexes as Highly Enantioselective Catalysts for Electrophilic Trifluoromethylthiolations
Authors: Deng Qing‐Hai , Rettenmeier Christoph , Wadepohl Hubert , Gade Lutz H.
Published: December 2013

The enantioselective trifluoromethylthiolation of β‐ketoesters using chiral copper–boxmi complexes as catalysts is reported. A number of α‐SCF3‐substituted β‐ketoesters have been obtained with up to >99 % enantiomeric excess (ee), and the trifluoromethylthiolated products were then transformed diastereoselectively to α‐SCF3‐β‐hydroxyesters with two adjacent quaternary stereocenters.
Combined Use of Warfarin and Oral P2Y12 Inhibitors in Patients With Atrial Fibrillation and Acute Coronary Syndrome
Authors: Jones W. Schuyler , Mi Xiaojuan , Patel Manesh R. , Mills Roger , Hernandez Adrian F. , Curtis Lesley H.
Published: December 2013

Background

Although atrial fibrillation (AF) occurs frequently in patients hospitalized with acute coronary syndrome (ACS), strategies for prevention of thromboembolic complications are poorly characterized.

Hypothesis

We sought to examine exposure to warfarin and P2Y12 inhibitors and clinical outcomes among patients with AF and ACS.

Methods

Patients age >65 years hospitalized with a primary diagnosis of ACS and a secondary diagnosis of AF between 2007 and 2010 were identified in the Medicare 5% sample. Medication exposure was ascertained during a 90‐day period following the index discharge using Medicare drug claims. Among patients who were alive and not readmitted during the ascertainment period, we examined the cumulative incidence of all‐cause mortality and all‐cause readmission by medication exposure at 1 year.

Results

A total of 2509 Medicare beneficiaries met the inclusion criteria. Among the 1633 patients (65%) who were alive and not readmitted during the 90‐day ascertainment period, 24.0% received warfarin, 38.9% received P2Y12 inhibitors, 10.2% received combination therapy, and 26.8% received neither therapy. Readmission rates were high in all groups at 1 year (warfarin, 47.5%; P2Y12 inhibitors, 46.6%; combination therapy, 38.0%; and neither therapy, 39.3%), and the overall 1‐year mortality rate was 12.5%.

Conclusions

Among Medicare beneficiaries with AF and ACS, combination therapy with warfarin and P2Y12 inhibitor was uncommon during the 90‐day ascertainment period, and more than one‐quarter of patients had no claims for warfarin or P2Y12 inhibitors. Rates of all‐cause readmission and mortality within 1 year of hospitalization for ACS were high.
The Synthesis and Biological Evaluation of Multifunctionalised Derivatives of Noscapine as Cytotoxic Agents
Authors: DeBono Aaron J. , Mistry Sarah J. , Xie Jinhan , Muthiah Divya , Phillips Jackson , Ventura Sabatino , Callaghan Richard , Pouton Colin W. , Capuano Ben , Scammells Peter J.
Published: December 2013

Noscapine, a phthalideisoquinoline alkaloid derived from Papaver somniferum, is a well‐known antitussive drug that has a relatively safe in vitro toxicity profile. Noscapine is also known to possess weak anticancer efficacy, and since its discovery, efforts have been made to design derivatives with improved potency. Herein, the synthesis of a series of noscapine analogues, which have been modified in the 6′, 9′, 1 and 7‐positions, is described. In a previous study, replacement of the naturally occurring N‐methyl group in the 6′‐position with an N‐ethylaminocarbonyl was shown to promote cell‐cycle arrest and cytotoxicity against three cancer cell lines. Here, this modification has been combined with other structural changes that have previously been shown to improve anticancer activity, namely halo substitution in the 9′‐position, regioselective O‐demethylation to reveal a free phenol in the 7‐position, and reduction of the lactone to the corresponding cyclic ether in the 1‐position. The incorporation of new aryl substituents in the 9′‐position was also investigated. The study identified interesting new compounds able to induce G2/M cell‐cycle arrest and that possess cytotoxic activity against the human prostate carcinoma cell line PC3, the human breast adenocarcinoma cell line MCF‐7, and the human pancreatic epithelioid carcinoma cell line PANC‐1. In particular, the ethyl urea cyclic ether noscapinoids and a compound containing a 6′‐ethylaminocarbonyl along with 9′‐chloro, 7‐hydroxy and lactone moieties exhibited the most promising biological activities, with EC50 values in the low micromolar range against all three cancer cell lines, and these derivatives warrant further investigation.