bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uracil‐Catalyzed Synthesis of Acetyl Phosphate: A Photochemical Driver for Protometabolism
Authors: Hagan William J. 
Published: December 2009

AbstractProgress toward a protometabolism (the earliest energy storage networks) has been severely hindered by a shortage of driver reactions, which could have harnessed solar photons or coupled electron sources/sinks on the primordial Earth. Here, it is reported for the first time that thioacetate can be converted into a known metabolite, acetyl phosphate, by ultraviolet light and in aqueous solution at neutral pH. Of more compelling importance, the synthesis is catalyzed by uracil, which suggests that a genetic component may have also facilitated the emergence of metabolic pathways. The chemistry of acetyl phosphate has been extensively studied, and it is known to be a precursor of phosphate esters, pyrophosphate and possibly longer inorganic chains. Moreover, its bifunctional reactivity (as either an acetyl or phosphoryl donor) would have been integral for the first metabolic cycles.
Ionic Liquids Based on Azolate Anions
Authors: Smiglak Marcin , Hines C. Corey , Wilson Timothy B. , Singh Shailendra , Vincek Adam S. , Kirichenko Kostyantyn , Katritzky Alan R. , Rogers Robin D. 
Published: December 2009

AbstractCompartmentalized molecular level design of new energetic materials based on energetic azolate anions allows for the examination of the effects of both cation and anion on the physiochemical properties of ionic liquids. Thirty one novel salts were synthesized by pairing diverse cations (tetraphenylphosphonium, ethyltriphenylphosphonium, N‐phenyl pyridinium, 1‐butyl‐3‐methylimidazolium, tetramethyl‐, tetraethyl‐, and tetrabutylammonium) with azolate anions (5‐nitrobenzimidazolate, 5‐nitrobenzotriazolate, 3,5‐dinitro‐1,2,4‐triazolate, 2,4‐dinitroimidazolate, 4‐nitro‐1,2,3‐triazolate, 4,5‐dinitroimidazolate, 4,5‐dicyanoimidazolate, 4‐nitroimidazolate, and tetrazolate). These salts have been characterized by DSC, TGA, and single crystal X‐ray crystallography. The azolates in general are surprisingly stable in the systems explored. Ionic liquids were obtained with all combinations of the 1‐butyl‐3‐methylimidazolium cation and the heterocyclic azolate anions studied, and with several combinations of tetraethyl‐ or tetrabutylammonium cations and the azolate anions. Favorable structure–property relationships were most often achieved when changing from 4‐ and 4,5‐disubstituted anions to 3,5‐ and 2,4‐disubstituted anions. The most promising anion for use in energetic ionic liquids of those studied here, was 3,5‐dinitro‐1,2,4‐triazolate, based on its contributions to the entire set of target properties.
Self‐Assembly of Ureido‐Pyrimidinone Dimers into One‐Dimensional Stacks by Lateral Hydrogen Bonding
Authors: Nieuwenhuizen Marko M. L. , de Greef Tom F. A. , van der Bruggen Rob L. J. , Paulusse Jos M. J. , Appel Wilco P. J. , Smulders Maarten M. J. , Sijbesma Rint P. , Meijer E. W. 
Published: December 2009

AbstractUreido‐pyrimidinone (UPy) dimers substituted with an additional urea functionality self‐assemble into one‐dimensional stacks in various solvents through lateral non‐covalent interactions. 1H NMR and DOSY studies in CDCl3 suggest the formation of short stacks (<10), whereas temperature‐dependent circular dichroism (CD) studies on chiral UPy dimers in heptane show the formation of much larger helical stacks. Analysis of the concentration‐dependent evolution of chemical shift in CDCl3 and the temperature‐dependent CD effect in heptane suggest that this self‐assembly process follows an isodesmic pathway in both solvents. The length of the aggregates is influenced by substituents attached to the urea functionality. In sharp contrast, UPy dimers carrying an additional urethane group do not self‐assemble into ordered stacks, as is evident from the absence of a CD effect in heptane and the concentration‐independent chemical shift of the alkylidene proton of the pyrimidinone ring in CDCl3.
Cluster‐Based Self‐Assembly Route toward MoO3 Single‐Walled Nanotubes
Authors: Hu Shi , Ling Xi , Lan Tian , Wang Xun 
Published: December 2009

AbstractMoO3 has a unique rigid double‐layer structure, which makes it a real challenge to prepare nanotubular structures. The controlled synthesis of MoO3 single‐walled nanotubes (SWNTs) is achieved through a cluster‐based self‐assembly route on the dodecanethiol/water interface. Various factors are studied at length, including precursor type, reaction time, temperature, pH value, and their influence on the morphology of products. The concept of “self‐assembly—from simple clusters to nanostructures” is proposed here based on preliminary results from the synthesis of MoO3 SWNTs, which provides a new aspect for traditional synthetic chemistry of nanomaterials and polyoxometalates.
Synthesis and Affinity Evaluation of a Small Library of Bidentate Cholera Toxin Ligands: Towards Nonhydrolyzable Ganglioside Mimics
Authors: Cheshev Pavel , Morelli Laura , Marchesi Marco , Podlipnik Črtomir , Bergström Maria , Bernardi Anna 
Published: December 2009

AbstractA small library of nonhydrolyzable mimics of GM1 ganglioside, featuring galactose and sialic acid as pharmacophoric carbohydrate residues, was synthesized and tested. All compounds were synthesized from readily available precursors using high‐performance reactions, including click chemistry protocols, and avoiding O‐glycosidic bonds. Some of the most active molecules also feature a point of further derivatization that can be used for conjugation with polyvalent aglycons. Their affinity towards cholera toxin was assessed by weak affinity chromatography, which allowed a systematic evaluation and selection of the best candidates. Affinity could be enhanced up to one or two orders of magnitude over the affinity of the individual pharmacophoric sugar residues.
A Panchromatic Supramolecular Fullerene‐Based Donor–Acceptor Assembly Derived from a Peripherally Substituted Bodipy–Zinc Phthalocyanine Dyad
Authors: Rio Yannick , Seitz Wolfgang , Gouloumis Andreas , Vázquez Purificacion , Sessler Jonathan L. , Guldi Dirk M. , Torres Tomás 
Published: December 2009

AbstractA panchromatic 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene –zinc phthalocyanine conjugate (Bodipy–ZnPc) 1 was synthesized starting from phthalocyanine aldehyde 4, via dipyrromethane 3 and dipyrromethene 2. Conjugate 1 represents the first example in which a Bodipy unit is tethered to the peripheral position of a phthalocyanine core. Electrochemical and optical measurements provided evidence for strong electronic interactions between the Bodipy and ZnPc constituents in the ground state of 1. When conjugate 1 is subjected to photoexcitation in the spectral region corresponding to the Bodipy absorption, the strong fluorescence characteristic of the latter subunit is effectively quenched (i.e., ≥97 %). Excitation spectral analysis confirmed that the photoexcited Bodipy and the tethered ZnPc subunits interact and that intraconjugate singlet energy transfer occurs with an efficiency of ca. 25 %. Treatment of conjugate 1 with N‐pyridylfulleropyrrolidine (8), an electron‐acceptor system containing a nitrogen ligand, gives rise to the novel electron donor–acceptor hybrid 1↔8 through ligation to the ZnPc center. Irradiation of the resulting supramolecular ensemble within the visible range leads to a charge‐separated Bodipy–ZnPc.+–C60.− radical‐ion‐pair state, through a sequence of excited‐state and charge transfers, characterized by a remarkably long lifetime of 39.9 ns in toluene.
Platinum Nanoparticles: The Crucial Role of Crystal Face and Colloid Stabilizer in the Diastereoselective Hydrogenation of Cinchonidine
Authors: Schmidt Erik , Kleist Wolfgang , Krumeich Frank , Mallat Tamas , Baiker Alfons 
Published: December 2009

AbstractThe preparation of stable metal nanoparticles requires a strong interaction between the (organic) stabilizer and the metal surface that might alter the catalytic properties. This behavior has been described as “poisoning” since the stabilizer normally decreases the catalytic activity due to site blocking. Here we show a striking influence of the stabilizer on the selectivity in the hydrogenation of cinchonidine (CD) over poly(acrylic acid) (PAA)‐stabilized Pt nanoparticles with well‐defined shape distributions. In the hydrogenation of the heteroaromatic ring of cinchonidine in toluene, the diastereomeric excess of the (S)‐hexahydrocinchonidine increased upon increasing Pt{111}/Pt{100} ratio, but this distinct shape selectivity was observed only after the oxidative removal of PAA at 473 K. The use of the as‐prepared nanoparticles inverted the major diastereomer to R, and this isomer was formed also in acetic acid. This striking change in the diastereoselectivity indicates that poly(acrylic acid), which remains on the Pt surface after preparation, interacts with CD during hydrogenation almost as strongly as the solvent acetic acid. The PAA stabilizer plays a dual role: it allows one to control the size and shape of the nanoparticles during their synthesis, and it affects the rate and diastereoselectivity of the hydrogenation of CD probably through a “surface‐localized acidification”.
Gold(I)‐Catalyzed Glycosylation with Glycosyl ortho‐Alkynylbenzoates as Donors: General Scope and Application in the Synthesis of a Cyclic Triterpene Saponin
Authors: Li Yao , Yang Xiaoyu , Liu Yunpeng , Zhu Cunsheng , Yang You , Yu Biao 
Published: December 2009

AbstractGlycosyl ortho‐alkynylbenzoates have emerged as a new generation of donors for glycosidation under the catalysis of gold(I) complexes such as Ph3PAuOTf and Ph3PAuNTf2 (Tf=trifluoromethanesulfonate). A wide variety of these donors, including 2‐deoxy sugar and sialyl donors, are easily prepared and shelf stable. The glycosidic coupling yields with alcohols are generally excellent; even direct coupling with the poorly nucleophilic amides gives satisfactory yields. Moreover, excellent α‐selective glycosylation with a 2‐deoxy sugar donor and β‐selective sialylation have been realized. Application of the present glycosylation protocol in the efficient synthesis of a cyclic triterpene tetrasaccharide have further demonstrated the versatility and efficacy of this new method, in that a novel chemoselective glycosylation of the carboxylic acid and a new one‐pot sequential glycosylation sequence have been implemented.
Cobalt‐Mediated Radical Coupling (CMRC): An Unusual Route to Midchain‐Functionalized Symmetrical Macromolecules
Authors: Debuigne Antoine , Poli Rinaldo , De Winter Julien , Laurent Pascal , Gerbaux Pascal , Dubois Philippe , Wathelet Jean‐Paul , Jérôme Christine , Detrembleur Christophe 
Published: December 2009

AbstractCobalt‐mediated radical coupling (CMRC) is a straightforward approach to the synthesis of symmetrical macromolecules that relies on the addition of 1,3‐diene compounds onto polymer precursors preformed by cobalt‐mediated radical polymerization (CMRP). Mechanistic features that make this process so efficient for radical polymer coupling are reported here. The mechanism was established on the basis of NMR spectroscopy and MALDI‐MS analyses of the coupling product and corroborated by DFT calculations. A key feature of CMRC is the preferential insertion of two diene units in the middle of the chain of the coupling product mainly according to a trans‐1,4‐addition pathway. The large tolerance of CMRC towards the diene structure is demonstrated and the impact of this new coupling method on macromolecular engineering is discussed, especially for midchain functionalization of polymers. It is worth noting that the interest in CMRC goes beyond the field of polymer chemistry, since it constitutes a novel carbon–carbon bond formation method that could be applied to small organic molecules.
Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover FeIII Complex into Bimetallic Oxalate‐Based Ferromagnets
Authors: Clemente‐León Miguel , Coronado Eugenio , López‐Jordà Maurici , Mínguez Espallargas Guillermo , Soriano‐Portillo Alejandra , Waerenborgh João C. 
Published: December 2009

AbstractThe syntheses, structures and magnetic properties of the compounds of formula [FeIII(sal2‐trien)][MnIICrIII(ox)3]⋅CH2Cl2 (1; H2sal2‐trien=N,N′‐disalicylidenetriethylenetetramine, ox=oxalate), [FeIII(sal2‐trien)][MnIICrIII(ox)3]⋅CH3OH (2), [InIII(sal2‐trien)][MnIICrIII(ox)3]⋅0.25 H2O ⋅0.25 CH3OH⋅0.25 CH3CN (3), and [InIII(sal2‐trien)][MnIICrIII(ox)3]⋅CH3NO2 ⋅0.5 H2O (4) are reported. The structure of 1 presents a 2D honeycomb anionic layer formed by MnII and CrIII ions linked through oxalate ligands and a cationic layer of [Fe(sal2‐trien)]+ complexes intercalated between the 2D oxalate network. The structures of 2, 3, and 4 present a 3D achiral anionic network formed by MnII and CrIII ions linked through oxalate ligands with [Fe(sal2‐trien)]+ or [In(sal2‐trien)]+ complexes and solvent molecules intercalated within the 3D oxalate network. The magnetic properties and Mössbauer spectroscopy of 1 and 2 indicate that these compounds undergo a long‐range ferromagnetic ordering at around 5 K and a spin crossover of the intercalated [Fe(sal2‐trien)]+ complexes above 130 K, which is complete in the case of 1. The magnetic properties of the compounds 3 and 4 confirm the ferromagnetic ordering of the bimetallic oxalate network.
Dynamic Kinetic Asymmetric Transformation (DYKAT) by Combined Amine‐ and Transition‐Metal‐Catalyzed Enantioselective Cycloisomerization
Authors: Zhao Gui‐Ling , Ullah Farman , Deiana Luca , Lin Shuangzheng , Zhang Qiong , Sun Junliang , Ibrahem Ismail , Dziedzic Pawel , Córdova Armando 
Published: December 2009

AbstractThe first examples of one‐pot highly chemo‐ and enantioselective dynamic kinetic asymmetric transformations (DYKATs) involving α,β‐unsaturated aldehydes and propargylated carbon acids are presented. These DYKATs, which proceed by a combination of catalytic iminium activation, enamine activation, and Pd0‐catalyzed enyne cycloisomerization, give access to functionalized cyclopentenes with up to 99 % eeand can be used for the generation of all‐carbon quaternary stereocenters.
Identification, SAR Studies, and X‐ray Co‐crystallographic Analysis of a Novel Furanopyrimidine Aurora Kinase A Inhibitor
Authors: Coumar Mohane Selvaraj , Tsai Ming‐Tsung , Chu Chang‐Ying , Uang Biing‐Jiun , Lin Wen‐Hsing , Chang Chun‐Yu , Chang Teng‐Yuan , Leou Jiun‐Shyang , Teng Chi‐Huang , Wu Jian‐Sung , Fang Ming‐Yu , Chen Chun‐Hwa , Hsu John T.‐A. , Wu Su‐Ying , Chao Yu‐Sheng , Hsieh Hsing‐Pang 
Published: December 2009

AbstractHerein we reveal a simple method for the identification of novel Aurora kinase A inhibitors through substructure searching of an in‐house compound library to select compounds for testing. A hydrazone fragment conferring Aurora kinase activity and heterocyclic rings most frequently reported in kinase inhibitors were used as substructure queries to filter the in‐house compound library collection prior to testing. Five new series of Aurora kinase inhibitors were identified through this strategy, with IC50 values ranging from ∼300 nM to ∼15 μM, by testing only 133 compounds from a database of ∼125 000 compounds. Structure–activity relationship studies and X‐ray co‐crystallographic analysis of the most potent compound, a furanopyrimidine derivative with an IC50 value of 309 nM toward Aurora kinase A, were carried out. The knowledge gained through these studies could help in the future design of potent Aurora kinase inhibitors.
Ovarian metastases from breast cancer
Authors: Bigorie Veronique , Morice Philippe , Duvillard Pierre , Antoine Martine , Cortez Annie , Flejou Jean François , Uzan Serge , Darai Emile , Barranger Emmanuel 
Published: December 2009

AbstractBACKGROUND:The objective of this study was to describe the characteristics and survival outcomes of patients with breast cancer who had ovarian metastases.METHODS:Data from 29 women who underwent surgery were reviewed retrospectively (from 1998 to 2007). Patient characteristics, tumor characteristics, and treatment data were collected. Pelvic extent of disease was documented using a system analogous to the International Federation of Gynecology and Obstetrics classification for ovarian cancer. Global survival, disease‐free intervals, and the distribution to other metastatic sites over time were studied. Outcomes were compared between the group who underwent macroscopic resection of lesions and the group who did not undergo resection.RESULTS:The data indicated a predominance of premenopausal and hormone receptor‐positive status and a greater prevalence of lobular infiltrating carcinoma, bilateral breast cancer, and predisposing genetic factors compared with the global population with breast cancer. Ovarian disease was diagnosed at a median of 5 years after breast cancer. Seventy‐five percent of patients were asymptomatic, and advanced‐stage pelvic extent or extra‐abdominal metastases were observed in 41.5% of patients. The median survival was 3 years, and the median follow‐up was 2 years. Survival improved significantly when optimal debulking surgery was performed.CONCLUSIONS:Breast cancers may be associated with ovarian metastases. The current results indicated that surgical resection tends to increase survival, which may be long; however, larger series would be needed to confirm other prognostic factors. The high rates of hormone receptor‐positive tumors and premenopausal patients led the authors to suggest that the surgical option should consist of at least bilateral oophorectomy, even when the contralateral ovary appears to be normal. Cancer 2010. © 2010 American Cancer Society.
Knowledge of hepatitis C virus screening in long‐term pediatric cancer survivors
Authors: Lansdale Meagan , Castellino Sharon , Marina Neyssa , Goodman Pamela , Hudson Melissa M. , Mertens Ann C. , Smith Stephanie M. , Leisenring Wendy , Robison Leslie L. , Oeffinger Kevin C. 
Published: December 2009

AbstractBACKGROUND:Pediatric cancer survivors who were treated before routine hepatitis C virus (HCV) screening of blood donors in 1992 have an elevated risk of transfusion‐acquired HCV.METHODS:To assess long‐term pediatric cancer survivors' knowledge of HCV testing and blood transfusion history, a questionnaire was administered to 9242 participants in the Childhood Cancer Survivor Study who are at risk for transfusion‐acquired HCV after cancer therapy from 1970 to 1986.RESULTS:More than 70% of survivors reported either no prior HCV testing (41%) or uncertainty about testing (31%), with only 29% reporting prior testing. One half recalled having a treatment‐related blood transfusion; those who recalled a transfusion were more likely to report HCV testing (39%) than those who did not (18%) or were unsure (20%). In multivariate models, survivors who reported no prior HCV testing were more likely to be older (odds ratio [OR] per 5‐year increase, 1.1; 95% confidence interval [CI], 1.0‐1.1) and to report no care at a cancer center within the past 2 years (OR, 1.2; 95% CI, 1.0‐1.4), no cancer treatment summary (OR, 1.3; 95% CI, 1.2‐1.5), and no transfusions (OR, 2.6; 95% CI, 2.3‐3.0) or uncertainty about transfusions (OR, 2.2; 95% CI, 1.9‐2.6), and less likely to be racial/ethnic minorities (OR, 0.9; 95% CI, 0.8‐1.0) or survivors of acute myeloid leukemia (OR, 0.7; 95% CI, 0.5‐1.0).CONCLUSIONS:Many pediatric cancer survivors at risk for transfusion‐acquired HCV are unaware of their transfusion history and prior testing for HCV and would benefit from programs to increase HCV knowledge and screening. Cancer 2010. © 2010 American Cancer Society.
Correlation of pretransplant and early post‐transplant response assessment with outcomes after reduced‐intensity allogeneic hematopoietic stem cell transplantation for non‐Hodgkin's lymphoma
Authors: Bishop Michael R. , Dean Robert M. , Steinberg Seth M. , Odom Jeanne , Pollack Seth M. , Pavletic Steven Z. , Sportes Claude , Gress Ronald E. , Fowler Daniel H. 
Published: December 2009

AbstractBACKGROUND:Chemotherapy sensitivity, defined simply as at least a partial response to chemotherapy, is an important outcome predictor for non‐Hodgkin lymphoma (NHL) patients undergoing reduced‐intensity allogeneic hematopoietic stem cell transplantation (allo‐HCT). The authors hypothesized that further differentiation of chemotherapy sensitivity by specific response, complete remission (CR) versus partial remission (PR) versus stable disease (SD) versus progression of disease (PD), correlates with post‐transplant outcomes.METHODS:The impact of pretransplant and early (28 days) post‐transplant disease response on transplant outcomes was analyzed in 63 NHL patients treated with reduced‐intensity allo‐HCT.RESULTS:The 3‐year event‐free survival (EFS) and overall survival (OS) (median potential follow‐up after reduced‐intensity allo‐HCT = 58 months) for all patients was 37% and 47%, respectively. The 3‐year EFS based on pretransplant response was: CR = 50%; PR = 66%; SD = 18%; no patient with PD pretransplant reached 3‐year follow‐up. The 3‐year OS based on pretransplant response was: CR = 63%; PR = 69%; SD = 45%. The 3‐year EFS based on post‐transplant response was: CR = 57%; PR = 32%; SD = 33%; no patient with PD post‐transplant reached 3‐year follow‐up. The 3‐year OS based on post‐transplant response was: CR = 65%; PR = 43%; SD = 50%. In multivariate analyses, pretransplant response was the best predictor of EFS (P< .0001). Pretransplant response (P< .0001) and age (P= .0035) were jointly associated with OS.CONCLUSIONS:These data suggest that NHL patients with pretransplant SD, generally considered inappropriate candidates, may benefit from reduced‐intensity allo‐HCT, and patients with pretransplant PD should only receive this therapy in clinical trials. Cancer 2010. © 2010 American Cancer Society.
Altered balance of γ‐aminobutyic acidergic and glutamatergic afferent inputs in rostral ventrolateral medulla‐projecting neurons in the paraventricular nucleus of the hypothalamus of renovascular hypertensive rats
Authors: Biancardi Vinicia Campana , Campos Ruy Ribeiro , Stern Javier Eduardo 
Published: December 2009

AbstractAn imbalance of excitatory and inhibitory functions has been shown to contribute to numerous pathological disorders. Accumulating evidence supports the idea that a change in hypothalamic γ‐aminobutyic acid (GABA)‐ergic inhibitory and glutamatergic excitatory synaptic functions contributes to exacerbated neurohumoral drive in prevalent cardiovascular disorders, including hypertension. However, the precise underlying mechanisms and neuronal substrates are still not fully elucidated. In the present study, we combined quantitative immunohistochemistry with neuronal tract tracing to determine whether plastic remodeling of afferent GABAergic and glutamatergic inputs into identified RVLM‐projecting neurons of the hypothalamic paraventricular nucleus (PVN‐RVLM) contributes to an imbalanced excitatory/inhibitory function in renovascular hypertensive rats (RVH). Our results indicate that both GABAergic and glutamatergic innervation densities increased in oxytocin‐positive, PVN‐RVLM (OT‐PVN‐RVLM) neurons in RVH rats. Despite this concomitant increase, time‐dependent and compartment‐specific differences in the reorganization of these inputs resulted in an altered balance of excitatory/inhibitory inputs in somatic and dendritic compartments. A net predominance of excitatory over inhibitory inputs was found in OT‐PVN‐RVLM proximal dendrites. Our results indicate that, along with previously described changes in neurotransmitter release probability and postsynaptic receptor function, remodeling of GABAergic and glutamatergic afferent inputs contributes as an underlying mechanism to the altered excitatory/inhibitory balance in the PVN of hypertensive rats. J. Comp. Neurol. 518:567–585, 2010. © 2010 Wiley‐Liss, Inc.