bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfilimine als vielseitige Nitrentransfer‐Reagenzien: Einfacher Zugang zu vielfältigen aza‐Heterocyclen
Authors: Tian Xianhai , Song Lina , Rudolph Matthias , Rominger Frank , Oeser Thomas , Hashmi A. Stephen K. 
Published: January 2019

AbstractWir berichten hier über die neue Synthese verschiedener biologisch wichtiger aza‐Heterocyclen mittels Sulfiliminen als Nitrentransfer‐Reagenzien. Diese Klasse von schwefelbasierten aza‐Yliden ist bisher für einen Gold‐Nitren‐Transfer nicht erfolgreich genutzt worden. In dieser Arbeit wird die effiziente Generierung von α‐Imino‐Gold‐Carbenen über eine N‐S‐Bindungsspaltung in Sulfiliminen gezeigt. Die Goldcarbene gehen C‐H‐Insertionen, Cyclopropanierungen und nukleophile Angriffe ein, die zu Indolen (44 Beispiele), 3‐Azabicyclo[3.1.0]hexan‐2‐iminen (24 Beispiele) und Imidazolen (3 Beispiele) führen. Diese Arbeit präsentiert die bisher unbekannte goldkatalysierte Reaktion zwischen Alkinen und Schwefelyliden. Zudem wird das erste Beispiel einer aza‐Heterocyclisierung über intermolekularen Nitrentransfer, gefolgt von der Cyclopropanierung des α‐Imino‐Goldcarbens, gezeigt. Sogar die unerwartete Synthese eines 4‐Acylchinolins (3 Beispiele) aus 2‐Acylphenylsulfiliminen und propargylischen Silyletherderivaten über eine 1,2‐Hydridverschiebung auf das α‐Imino‐Goldcarben und eine nachfolgende Mukaiyama‐Aldol‐Cyclisierung wurde entdeckt.
Structural Snapshots of Cluster Growth from {U6} to {U38} During the Hydrolysis of UCl4
Authors: Chatelain Lucile , Faizova Radmila , Fadaei‐Tirani Farzaneh , Pécaut Jacques , Mazzanti Marinella 
Published: January 2019

AbstractHerein we report the assembly of large uranium(IV) clusters with novel nuclearities and/or shapes from the controlled hydrolysis of UCl4 in organic solution and in the presence of the benzoate ligands. {U6}, {U13}, {U16}, {U24}, {U38} oxo and oxo/hydroxo clusters were isolated and crystallographically characterized. These structural snapshots indicate that larger clusters are slowly built from the condensation of octahedral {U6} building blocks. The uranium/benzoate ligand ratio, the reaction temperature and the presence of base play an important role in determining the structure of the final assembly. Moreover, the isolation of different size cluster {U6} (few hours), {U16} (3 days), {U24} (21 days) from the same solution in a chosen set of conditions shows that the assembly of uranium oxo clusters in hydrolytic conditions is time dependent.
Umpolung Reactivity of Ynamides: An Unconventional [1,3]‐Sulfonyl and [1,5]‐Sulfinyl Migration Cascade
Authors: Prabagar B. , Mallick Rajendra K. , Prasad Rangu , Gandon Vincent , Sahoo Akhila K. 
Published: January 2019

AbstractA regioselective sulfonyl/sulfinyl migration cycloisomerization cascade of alkyne‐tethered ynamides is developed in the presence of XPhosgold catalyst. This reaction is the first example of a general [1,3]‐sulfonyl migration from the nitrogen center to the β‐carbon atom of ynamides, followed by umpolung 5‐endo‐dig cyclization of the ynamide α‐carbon atom to the gold‐activated alkyne, and final deaurative [1,5]‐sulfinylation. This process allows the synthesis of peripherally decorated unconventional 4‐sulfinylated pyrroles with broad scope from N‐propargyl‐tethered ynamides. In contrast, N‐homopropargyl‐tethered ynamides undergo intramolecular tetradehydro Diels–Alder reaction to provide 2,3‐dihydro‐benzo[f]indole derivatives. Control experiments and density‐functional theory studies were used to study the reaction pathways.
Chemical Regulation of DNA i‐Motifs for Nanobiotechnology and Therapeutics
Authors: Debnath Manish , Fatma Khushnood , Dash Jyotirmayee 
Published: January 2019

AbstractDNA sequences rich in cytosine have the propensity, under acidic pH, to fold into four‐stranded intercalated DNA structures called i‐motifs. Recent studies have provided significant breakthroughs that demonstrate how chemists can manipulate these structures for nanobiotechnology and therapeutics. The first section of this Minireview discusses the development of advanced functional nanostructures by synthetic conjugation of i‐motifs with organic scaffolds and metal nanoparticles and their role in therapeutics. The second section highlights the therapeutic targeting of i‐motifs with chemical scaffolds and their significance in biology. For this, first we shed light on the long‐lasting debate regarding the stability of i‐motifs under physiological conditions. Next, we present a comparative analysis of recently reported small molecules for specifically targeting i‐motifs over other abundant DNA structures and modulating their function in cellular systems. These advances provide new insights into i‐motif‐targeted regulation of gene expression, telomere maintenance, and therapeutic applications.
The Bacterial [Fe]‐Hydrogenase Paralog HmdII Uses Tetrahydrofolate Derivatives as Substrates
Authors: Watanabe Tomohiro , Wagner Tristan , Huang Gangfeng , Kahnt Jörg , Ataka Kenichi , Ermler Ulrich , Shima Seigo 
Published: January 2019

Abstract[Fe]‐hydrogenase (Hmd) catalyzes the reversible hydrogenation of methenyl‐tetrahydromethanopterin (methenyl‐H4MPT+) with H2. H4MPT is a C1‐carrier of methanogenic archaea. One bacterial genus, Desulfurobacterium, contains putative genes for the Hmd paralog, termed HmdII, and the HcgA–G proteins. The latter are required for the biosynthesis of the prosthetic group of Hmd, the iron–guanylylpyridinol (FeGP) cofactor. This finding is intriguing because Hmd and HmdII strictly use H4MPT derivatives that are absent in most bacteria. We identified the presence of the FeGP cofactor in D. thermolithotrophum. The bacterial HmdII reconstituted with the FeGP cofactor catalyzed the hydrogenation of derivatives of tetrahydrofolate, the bacterial C1‐carrier, albeit with low enzymatic activities. The crystal structures show how Hmd recognizes tetrahydrofolate derivatives. These findings have an impact on future biotechnology by identifying a bacterial Hmd paralog.
One‐Dimensional Fe2P Acts as a Fenton Agent in Response to NIR II Light and Ultrasound for Deep Tumor Synergetic Theranostics
Authors: Liu Yang , Zhen Wenyao , Wang Yinghui , Liu Jianhua , Jin Longhai , Zhang Tianqi , Zhang Songtao , Zhao Ying , Song Shuyan , Li Chengyu , Zhu Junjie , Yang Yang , Zhang Hongjie 
Published: January 2019

AbstractThe stringent reaction conditions for an effective Fenton reaction (pH range of 3–4) hinders its application in cancer therapy. Therefore, how to improve the efficiency of the Fenton reaction in a tumor site has been the main obstacle in chemodynamic therapy (CDT). Herein, we report biocompatible one‐dimensional (1D) ferrous phosphide nanorods (FP NRs) with ultrasound (US)‐ and photothermal (PT)‐enhanced Fenton properties and excellent photothermal conversion efficiency (56.6 %) in the NIR II window, showing synergistic therapeutic properties. Additionally, the high photothermal conversion efficiency and excellent traverse relaxivity (277.79 mm−1 s−1) of the FP NRs means they are excellent photoacoustic imaging (PAI) and magnetic resonance imaging (MRI) agents. This is the first report on exploiting the response of metallic phosphides to NIR II laser (1064 nm) and ultrasound to improve the CDT effect with a high therapeutic effect and PA/MR imaging.
Anchoring an Artificial Solid–Electrolyte Interphase Layer on a 3D Current Collector for High‐Performance Lithium Anodes
Authors: Li Panlong , Dong Xiaoli , Li Chao , Liu Jingyuan , Liu Yao , Feng Wuliang , Wang Congxiao , Wang Yonggang , Xia Yongyao 
Published: January 2019

AbstractThe application of Li anodes is hindered by dendrite growth and side reactions between Li and electrolyte, despite its high capacity and low potential. A simple approach for this challenge is now demonstrated. In our strategy, the garnet‐type Li6.4La3Zr1.4Ta0.6O12 (LLZTO)‐based artificial solid–electrolyte interphase (SEI) is anchored on Cu foam by sintering the Cu foam coated with LLZTO particles. The heat treatment leads to the interdiffusion of Cu and Ta2O5 at the Cu/LLZTO interface, through which LLZTO layer is fixed on Cu foam. 3D structure lowers the current density, and meanwhile the SEI reduces the contact of Li and electrolyte. Furthermore, the anchoring construction can endure Li‐deposition‐induced volume change. Therefore, LLZTO‐modified Cu foam shows much improved Li plating/stripping performance, including long lifespan (2400 h), high rate (maximum current density of 20 mA cm−2), high areal capacity (8 mA h cm−2 for 100 cycles), and high efficiency (over 98 %).
Stereoselective Total Synthesis of Eburnane‐Type Alkaloids Enabled by Conformation‐Directed Cyclization and Rearrangement
Authors: Li Guang , Piemontesi Cyril , Wang Qian , Zhu Jieping 
Published: January 2019

AbstractControlling the cis C20/C21 relative stereochemistry remains an unsolved issue in the synthesis of eburnane‐type indole alkaloids. Provided herein is a simple solution to this problem by developing a unified and diastereoselective synthesis of four representative members of this class of natural products, namely, eburnamonine, larutensine, terengganensine B, and melokhanine E. The synthesis features the following key steps: a) an α‐iminol rearrangement transforming the 3‐hydroxyindolenine into spiroindolin‐3‐one, b) a highly diastereoselective conformation‐directed cyclization leading to the melokhanine skeleton with the desired C20/C21 cis stereochemistry, and c) either an aza‐pinacol or an unprecedented α‐aminoketone rearrangement converting spiroindolinone back into the indole skeleton.
Asymmetric and Geometry‐Selective α‐Alkenylation of α‐Amino Acids
Authors: Abas Hossay , Mas‐Roselló Josep , Amer Mostafa Mahmoud , Durand Derek J. , Groleau Robin R. , Fey Natalie , Clayden Jonathan 
Published: January 2019

AbstractBoth E‐ and Z‐N′‐alkenyl urea derivatives of imidazolidinones may be formed selectively from enantiopure α‐amino acids. Generation of their enolate derivatives in the presence of K+ and [18]crown‐6 induces intramolecular migration of the alkenyl group from N′ to Cα with retention of double bond geometry. DFT calculations indicate a partially concerted substitution mechanism. Hydrolysis of the enantiopure products under acid conditions reveals quaternary α‐alkenyl amino acids with stereodivergent control of both absolute configuration and double bond geometry.
Constructing Mononuclear Palladium Catalysts by Precoordination/Solvothermal Polymerization: Recyclable Catalyst for Regioselective Oxidative Heck Reactions
Authors: Li Wen‐Hao , Li Cun‐Yao , Xiong Huan‐Yan , Liu Yang , Huang Wen‐Yong , Ji Guang‐Jun , Jiang Zheng , Tang Hai‐Tao , Pan Ying‐Ming , Ding Yun‐Jie 
Published: January 2019

AbstractHeterogeneous, metal, single‐site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stable mononuclear Pd‐metalized porous organic polymer catalyst (Pd@POP). Pd@POP was easy to use in regioselective organic reactions because the internal structure of this Pd@POP can be easily modified. The catalyst was used to solve the intractable regioselectivity problems of Heck reactions. Pd@POP‐9 can efficiently activate the ends of olefins, thereby leading to high selectivity for substitution at the external position. To understand the reason underlying the high selectivity and activity of the catalyst, the systemic characterization of Pd@POP‐9 and density‐functional theory calculations were conducted. This Heck reaction is the first to be catalyzed by a recyclable mononuclear metal catalyst with unprecedented catalytic activity and regioselectivity.
Enantioselective Synthesis of 3,3′‐Diaryl‐SPINOLs: Rhodium‐Catalyzed Asymmetric Arylation/BF3‐Promoted Spirocyclization Sequence
Authors: Yin Long , Xing Junhao , Wang Yuhan , Shen Yue , Lu Tao , Hayashi Tamio , Dou Xiaowei 
Published: January 2019

AbstractThe enantioselective synthesis of a series of C2‐symmetric 3,3′‐diarylated 1,1′‐spirobiindane‐7,7′‐diols (3,3′‐diaryl‐SPINOLs) was developed by sequential Rh‐catalyzed twofold asymmetric conjugate arylation/BF3‐promoted diastereoselective spirocyclization (>20:1 d.r. and >99 % ee for all examples). Some phosphoramidite ligands were prepared from the 3,3′‐Ph‐SPINOL and applied to several catalytic asymmetric reactions, and the 3,3′‐diarylated ligands showed higher enantioselectivities than the privileged nonsubstituted ligands.
Isolation, synthesis, and cytotoxicity evaluation of two impurities in nomegestrol acetate
Authors: Xie Bao‐Cheng , Song Shu‐Yong , Xie Xiao‐Yang , Sun Yu‐Tong , Zhang Xiao‐Yuan , Xu Dao‐Hua , Huang Yun‐Sheng 
Published: January 2019

AbstractNomegestrol acetate (NOMAc) is a synthetic progesterone analog and classified as a fourth‐generation progestin. It has been approved in many countries for oral contraception, hormonal replacement therapy (HRT), and treatment of various gynecological disorders. There are several synthetic routes reported for the synthesis of NOMAc and they all share the very similar last three to five steps toward the conversion of 6‐methylene to 6‐methyl‐6,7‐unsaturated structure. Therefore the final product from different processing routes may have similar impurity profiles. In the analysis of NOMAc, we identified two impurities, impurity A (listed in EP 8.0) and impurity B (not specified in EP 8.0). Both impurities were further confirmed by synthesis. In addition, both impurities and NOMAc were evaluated for their in vitro cytotoxicities against L02 liver cells, mesenchymal stem cells, MCF‐7 breast cancer cells, and C33A cervical cancer cells. These three analogs are not cytotoxic to the four cell lines at low concentrations (<20 μM). NOMAc and impurity A showed cytotoxicity to L02, MCF‐7, and C33A cells at high concentrations, while impurity B did not show significant cytotoxicity to any of the cell lines tested.
Unique Substitution Effect at 5,5′‐Positions of Fused Azobenzene–Boron Complexes with a N=N π‐Conjugated System
Authors: Gon Masayuki , Wakabayashi Junko , Tanaka Kazuo , Chujo Yoshiki 
Published: January 2019

AbstractA recent report illustrated superior optical properties, such as near‐infrared emission, of polymers connected at the 4,4′‐positions to a fused azobenzene–boron complex (BAz). In this study, it is initially demonstrated that further narrowing of the band gap can be realized through the substituent effect with bromine groups at the 5,5′‐positions of BAz compared with those at the 4,4′‐positions. From a series of mechanistic studies, perturbation of the energy levels was rationally explained by the difference in contributions of the inductive effect and the variable resonance effect, which was correlated with the degree of electron distribution of molecular orbitals at the substituent positions. Moreover, it was found that unique electronic states, such as delocalized HOMOs and LUMOs, should appear on the main chains of the BAz‐containing copolymers with fluorene and bithiophene units, according to the optical and electrochemical data and theoretical calculations. By taking advantage of property tunability and the dramatically low LUMO energy level (near −4.0 eV) of the BAz unit, it can be said that BAz should be a conjugated building block favorable for building advanced optoelectronic devices.
Chiral Sensing Using Circularly Polarized Luminescence of Bis(phenanthroline dicarboxylic acid) EuIII Complex Induced by Allosteric‐type Interaction with Amino Acid Molecules
Authors: Iwamura Munetaka , Fujii Mai , Yamada Ayano , Koike Hikaru , Nozaki Koichi 
Published: January 2019

Abstract[Eu(pda)2]− and [Eu(bda)2]− (pda=1,10‐phenanthroline‐2, 9‐dicarboxylic acid; bda=2,2′ bipyridine 5,5′‐dicarboxylic acid) have an achiral D2d structure in crystals. These complexes exhibit circularly polarized luminescence (CPL) in water containing chiral amino acids. In this work, induced CPL of [Eu(pda)2]− and [Eu(bda)2]− in water solutions containing a mixture of d‐ and l‐ amino acids were examined. Plots of glum values of the induced CPL as a function of mol‐fraction of l‐ and d‐ arginine reveal that [Eu(pda)2]− favors homo‐association ([Eu(pda)2]−‐(l‐arginine)2 or [Eu(pda)2]−‐(d‐arginine)2) over hetero‐association {[Eu(pda)2]−‐(l‐arginine)⋅(d‐arginine)}. This suggests that association of an arginine molecule induces a structural change in [Eu(pda)2]− to promote chiral selective association to another arginine, i.e., homo‐allosteric association. On the other hand, the system of [Eu(pda)2]− with histidine favors hetero‐allosteric association over homo‐association. No allosteric effect is recognized in CPL from [Eu(bda)2]−.
Does integrated reporting information influence internal decision making? An experimental study of investment behavior
Authors: Esch Martin , Schnellbächer Benedikt , Wald Andreas 
Published: January 2019

AbstractSustainable value creation has moved to the center of attention of many companies, leading to a shift in external corporate reporting. Sustainability information is provided within sustainability reports and CSR reports as well as integrated reports. Research has considered the motivations and different formats of integrated reports and how these reports provide a better information basis for investors. However, integrated reporting information may also affect internal decision making by providing decision makers with a more comprehensive picture of the impact of the firm's strategy. Here, we present the results of a scenario‐based experiment testing how financial, unlinked financial and nonfinancial, and integrated information affect the outcomes of investment decisions. We find that an integrated information basis leads to decisions with higher sustainable value creation. We thus show that information prepared for external reporting can also be used for internal purposes to help companies establish sustainable decision behavior.
Cervical cancer screening history prior to a diagnosis of cervical cancer in Danish women aged 60 years and older—A national cohort study
Authors: Hammer Anne , Soegaard Vibeke , Maimburg Rikke D. , Blaakaer Jan 
Published: January 2019

AbstractThe incidence and mortality of cervical cancer are high in Danish women aged 60 years and older who are about to exit the cervical cancer screening program. The present study aimed to describe the screening history in women ≥60 years old, diagnosed with cervical cancer in Denmark, 2009‐2013. We retrieved information on cases of cervical cancer and previous cervical cancer screening from national registries. During the study period, a total of 1907 women were diagnosed with cervical cancer, 574 (30.1%) of which were ≥60 years old. The majority of women were diagnosed with squamous cell carcinoma (73.7%) and advanced‐stage disease (ASD, ie, ≥FIGO IIB; 63.1%). The proportion of ASD increased with age, from 51.9% in women aged 60‐64% to 76.7% in women aged 75‐79. Among screened women (n = 377), 22.8% had a cervical cytology within 5 years of diagnosis, 73.3% of which were normal, and 45.1% were diagnosed with ASD. Women who had been sufficiently screened prior to screening exit (≥2 normal cytology test in the age interval 50‐59) accounted for 18.1%. Of note, 53.8% of the sufficiently screened women were diagnosed with ASD. Sufficiently screened women were less likely to be diagnosed with ASD compared to never‐screened women (53.8% vs 67.5%, P < 0.020), but no difference was observed between sufficiently and insufficiently screened women (53.8% vs 63.4%, P = 0.091). Our findings suggest that cancer in older women may occur due to insufficient screening prior to screening exit, a low sensitivity of screening, and premature screening exit.
Novel Aminomethyl Derivatives of 4‐Methyl‐2‐prenylphenol: Synthesis and Antioxidant Properties
Authors: Buravlev Evgeny V. , Fedorova Irina V. , Shevchenko Oksana G. , Kutchin Aleksandr V. 
Published: January 2019

Abstract4‐Methyl‐2‐prenylphenol (1) was synthesized from para‐cresol and prenol, natural alcohol under the conditions of heterogeneous catalysis. A series of nine new aminomethyl derivatives with secondary and tertiary amino groups were obtained on the basis of compound 1. A comparative evaluation of their antioxidant properties was carried out using in vitro models. It was established that Mannich base with octylaminomethyl group has radical‐scavenging activity, high Fe2+‐chelation ability as well as the ability to inhibit oxidative hemolysis of red blood cells.
Chemoselective Hydrogenation of α,β‐Unsaturated Carbonyls Catalyzed by Biomass‐Derived Cobalt Nanoparticles in Water
Authors: Song Tao , Ma Zhiming , Yang Yong 
Published: January 2019

AbstractHerein, we report highly chemoselective hydrogenation of α,β‐unsaturated carbonyls to saturated carbonyls catalyzed by cobalt nanoparticles supported on the biomass‐derived carbon from bamboo shoots with molecular hydrogen in water, which is the first prototype using a heterogeneous non‐noble metal catalyst for such organic transformation as far as we know. The optimal cobalt nanocatalyst, CoOx@NC‐800, manifested remarkable activity and selectivity for hydrogenation of C=C in α,β‐unsaturated carbonyls under mild conditions. A broad set of α,β‐aromatic and aliphatic unsaturated carbonyls were selectively reduced to their corresponding saturated carbonyls in up to 99 % yields with good tolerance of various functional groups. Meanwhile, a new straightforward one‐pot cascade synthesis of saturated carbonyls was realized with high activity and selectivity via the cross‐aldol condensation of ketones with aldehydes followed by selective hydrogenation. More importantly, this one‐pot strategy is applicable for the expedient synthesis of Loureirin A, a versatile bioactive and medicinal molecule, from readily available starting materials, further highlighting the practical utility of the catalyst. In addition, the catalyst can be easily separated for successive reuses without significant loss in both activity and selectivity.
Monocrystal Cu3Mo2O9 Confined in Polyaniline Protective Layer: an Effective Strategy for Promoting Lithium Storage Stability
Authors: Zhang Yang , Zhao Ganggang , Jiang Yunling , Hong Wanwan , Zhang Yu , Deng Mingxiang , Shuai Honglei , Xu Wei , Zou Guoqiang , Hou Hongshuai , Ji Xiaobo 
Published: January 2019

AbstractAttributed to the high theoretical capacity and abundant reserve, Cu3Mo2O9 has been considered as a potential anode material for lithium‐ion batteries. Nevertheless, the severe capacity fading caused by structure collapse and particle aggregation seriously hinders its practical application. In this work, Cu3Mo2O9 coated with homogeneous polyaniline layer is obtained through oxidative polymerization of aniline on the surface of Cu3Mo2O9. The lithium storage performance is investigated systematically. As a result, a high reversible specific capacity of 800.2 mA h g−1 at a current density of 100 mA g−1 is delivered in Cu3Mo2O9@PANI anode even after 200 cycles, which is much higher than that of pristine Cu3Mo2O9 anode (373.8 mA h g−1). Furthermore, a high capacity of 675 mA h g−1 at a high current density of 1 A g−1 is achieved even after 700 cycles. This result evidences that the introduction of a polyaniline protective layer is an effective way to improve the structural stability of the Cu3Mo2O9 anode and further enhance cycling durability. This strategy is a starting point for the preparation and stabilization of other binary metal oxide composite materials for applications in lithium‐ion batteries.