bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous isolation of artemisinin and its precursors from Artemisia annua L. by preparative RP‐HPLC
Authors: Tian Na , Li Juan , Liu Shuoqian , Huang Jianan , Li Xun , Liu Zhonghua 
Published: September 2011

ABSTRACTIt is still a major challenge to simultaneously isolate artemisinin and its precursors, especially dihydroartemisinic acid and artemisinic acid, from herbal Artemisia annua. A rapid, economical and automatical chromatographic separation process to isolate and purify artemisinin, dihydroartemisinic acid and artemisinic acid at the same time on a preparative scale was developed. The procedure included solvent extraction of ground Artemisia annua leaves by refluxing and purification of crude extract by preparative reverse‐phase high‐performance liquid chromatography (RP‐HPLC). Fractions containing artemisinin and its precursors were collected and identified by gas chromatography and mass spectrometry. High purity of artemisinin, dihydroartemisinic acid and artemisinic acid was obtained by preparative HPLC with a C18 column and 60% acetonitrile in water as the mobile phase. The techniques described here are useful tools for the preparative‐scale isolation of artemisinin and its precursors in a fast, cost‐effective and environmental friendly manner. Copyright © 2011 John Wiley & Sons, Ltd.
Reductive Elimination of ArCF3 from Bidentate PdII Complexes: A Computational Study
Authors: Anstaett Philipp , Schoenebeck Franziska 
Published: September 2011

AbstractThe reductive eliminations of ArCF3 from PdII complexes bearing small‐ and large‐bite‐angle phosphane ligands have been investigated using computational methods. QM/QM′ and QM/MM studies were applied and complemented with CP2 K molecular dynamics investigations. The ligand substituents were varied and a decomposition analysis was performed to allow us to gain insights into the steric and electronic properties of the ligands. The greater reactivity of Xantphos‐derived (Xantphos=4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene) complexes in the reductive elimination of ArCF3 is primarily due to the lower repulsive effect of the phoshine substituents in the transition state than in the reactant complex, combined with the increased electronic interaction in the transition state. For DPPE (1,2‐bis(diphenylphosphino)ethane), the steric effect of the ligand substituents is greater in the transition state, leading to a higher reaction barrier overall for reductive elimination. There is no direct correlation of the reactivity with the bite angle of the reactant complexes. Only for complexes with large ligand substituents may the bite angle of the Pd complexes be used as a guide for reactivity.
Is Electronegativity a Useful Descriptor for the Pseudo‐Alkali Metal NH4?
Authors: Whiteside Alexander , Xantheas Sotiris S. , Gutowski Maciej 
Published: September 2011

AbstractMolecular ions in the form of “pseudo‐atoms” are common structural motifs in chemistry, with properties that are transferrable between different compounds. We have determined one such property—the electronegativity—for the “pseudo‐alkali metal” ammonium (NH4), and evaluated its reliability as a descriptor versus the electronegativities of the alkali metals. The computed properties of ammonium’s binary complexes with astatine and of selected borohydrides confirm the similarity of NH4 to the alkali metal atoms, although the electronegativity of NH4 is relatively large in comparison to its cationic radius. We have paid particular attention to the molecular properties of ammonium (angular anisotropy, geometric relaxation and reactivity), which can cause deviations from the behaviour expected of a conceptual “true alkali metal” with this electronegativity. These deviations allow for the discrimination of effects associated with the molecular nature of NH4.
ChemInform Abstract: Ni‐Catalyzed Ketene Cycloaddition: A System that Resists the Formation of Decarbonylation Side Products.
Authors: Kumar Puneet , Troast Dawn M. , Cella Rodrigo , Louie Janis 
Published: September 2011

AbstractIn the title reaction, 2,4‐cyclohexadienones are formed instead of products which arise from decarbonylation of the ketenes.
ChemInform Abstract: Gold and Broensted Acid Catalyzed Hydride Shift onto Allenes: Divergence in Product Selectivity.
Authors: Bolte Benoit , Gagosz Fabien 
Published: September 2011

AbstractCyclic and benzyl allenyl ethers can be transformed into various spiro tetrahydrofurans and tetrahydropyrans following a hydride shift / cyclization sequence.
ChemInform Abstract: Preparation of Unsymmetrical Dialkyl Acetylenedicarboxylates and Related Esters by Enzymatic Transesterification.
Authors: Sultan Nisrine , Thomas Coralie , Blanco Luis , Deloisy Sandrine 
Published: September 2011

AbstractSymmetrical acetylene dicarboxylates undergo an unexpected highly selective mono‐transesterification with various alcohols in the presence of Candida rugosa lipase.
ChemInform Abstract: Asymmetric Neutral Amination of Nitroolefins Catalyzed by Chiral Bifunctional Ammonium Salts in Water‐Rich Biphasic Solvent.
Authors: Wang Lijia , Shirakawa Seiji , Maruoka Keiji 
Published: September 2011

AbstractA highly efficient organocatalyzed asymmetric amination of nitroolefins is presented.
ChemInform Abstract: Modular Amino Acid Amide Chiral Ligands for Enantioselective Addition of Diethylzinc to Aromatic Aldehydes.
Authors: Gou Shaohua , Ye Zhongbin , Chang Jing , Gou Guangjun , Feng Mingming 
Published: September 2011

AbstractAmong 9 ligands tested, the derivative AAA is found to be the most efficient one and the e.e.
ChemInform Abstract: InBr3‐Catalyzed Deoxygenation of Carboxylic Acids with a Hydrosilane: Reductive Conversion of Aliphatic or Aromatic Carboxylic Acids to Primary Alcohols or Diphenylmethanes.
Authors: Sakai Norio , Kawana Keita , Ikeda Reiko , Nakaike Yumi , Konakahara Takeo 
Published: September 2011

AbstractA variety of carboxylic acids is converted to primary alcohols applying InBr3 as a catalyst and tetramethyldisoxane as a reducing agent [cf.
ChemInform Abstract: The First Heterogeneous Sonogashira Coupling Reaction of Aryl Halides with Terminal Alkynes Catalyzed by Diatomite‐Supported Palladium(II) Salophen Complex.
Authors: Bahramian Bahram , Bakherad Mohammad , Keivanloo Ali , Bakherad Zohre , Karrabi Behzad 
Published: September 2011

AbstractThe new catalyst is air‐stable and can be reused at least 5 times without any decrease in activity.
ChemInform Abstract: Dual IGF‐1R/SRC Inhibitors Based on a N′‐Aroyl‐2‐(1H‐indol‐3‐yl)‐2‐oxoacetohydrazide Structure.
Authors: Schmidt Stefanie , Preu Lutz , Lemcke Thomas , Totzke Frank , Schaechtele Christoph , Kubbutat Michael H. G. , Kunick Conrad 
Published: September 2011

AbstractBenzoic acid hydrazides (III) and (VI) are reacted with indolyloxoacetyl chloride (IV) to afford N,N′‐diacylated hydrazides (V) and (VII).
ChemInform Abstract: Phosphonium Ion Tagged Chiral Phosphoric Acids and Their Application in Friedel—Crafts Reactions of Indoles.
Authors: Hermeke Julia , Toy Patrick H. 
Published: September 2011

AbstractThe new CPA is used in reactions of indoles with enamides (II) and β,γ‐unsaturated α‐keto esters (IV) to give alkylated indoles.
ChemInform Abstract: Stereoselective Synthesis of Polyoxygenated Linear Diaza‐Triquinanes via Intramolecular 1,3‐Dipolar Cycloaddition of Sugar‐Derived Hex‐5‐enals.
Authors: Li Yunfeng , Meng Yao , Meng Xiangbao , Li Zhongjun 
Published: September 2011

AbstractCycloaddition of various chiral hexenals with pyrazolidinones results in the stereoselective formation of diaza‐triquinane derivatives.
ChemInform Abstract: Synthesis of Benzimidazoles by Phosphine‐Mediated Reductive Cyclization of ortho‐Nitro‐anilides.
Authors: Duchek Jan , Vasella Andrea 
Published: September 2011

AbstractThe reactions of ortho‐nitroanilides and the pyridine‐derived analogue (XI) afford the 2‐substituted benzimidazoles and imidazopyridine respectively.
ChemInform Abstract: Cascade Formation of Isoxazoles: Facile Base‐Mediated Rearrangement of Substituted Oxetanes.
Authors: Burkhard Johannes A. , Tchitchanov Boris H. , Carreira Erick M. 
Published: September 2011

AbstractA novel synthesis of formylisoxazoles is presented, involving a tertiary amine‐mediated cascade Henri addition—elimination—rearrangement reaction of nitroalkanes (I), (IV) or (VI) with oxetanone (II).
ChemInform Abstract: Reactions of 2‐Benzylidenemalononitrile and 2‐Nitro‐3‐phenylacrylonitrile with Aryl Azides.
Authors: Nosachev S. B. , Shchurova N. A. , Tyrkov A. G. 
Published: September 2011

AbstractReactions of the title nitriles with aryl azides in Et2O give mixtures of regioisomeric triazoles, whilst aziridine derivatives are formed in refluxing CHCl3.
ChemInform Abstract: Model Route to 5‐Bromo‐3,4‐dihydro‐4‐hydroxy‐7,9,10‐trimethoxy‐1,3‐dimethyl‐1H‐naphtho[ 2,3‐c]pyran: A Potential Precursor to Extended Quinones.
Authors: Mei Mawonga N. , Hugo Victor I. , Green Ivan R. 
Published: September 2011

AbstractThe main purpose of the bromine atom at position 4′ is to favor cyclization at position 2′.
ChemInform Abstract: Diastereoselective Three‐Step Route to o‐(6‐Nitrocyclohex‐3‐en‐1‐yl)phenol and Tetrahydro‐6H‐benzo[c]chromen‐6‐ol Derivatives from Salicylaldehydes.
Authors: Lanari Daniela , Ballini Roberto , Palmieri Alessandro , Pizzo Ferdinando , Vaccaro Luigi 
Published: September 2011

AbstractCyclocondensation of salicylic aldehydes (I) with acetoacetate proceeds under solvent‐free conditions in the presence of a solid‐phase catalyst to give 3‐acetylcoumarins (III) [3‐nitrocoumarins (X) are formed analogously].
ChemInform Abstract: Synthesis of Novel 1,2,4‐Oxadiazoles and Analogues as Potential Anticancer Agents.
Authors: Kumar Dalip , Patel Gautam , Chavers Angela K. , Chang Kuei‐Hua , Shah Kavita 
Published: September 2011

AbstractThe key step in the synthesis of oxadiazoles (III) involves coupling of amidoxime (I) with a carboxylic acid (II) followed by thermal cyclization.
ChemInform Abstract: Synthesis and Antitumor Activity of 2‐Amino‐3‐cyano‐6‐(1H‐indol‐3‐yl)‐4‐phenylpyridine Derivatives in vitro.
Authors: Zhang Fan , Zhao Yanfang , Sun Li , Ding Lu , Gu Yucheng , Gong Ping 
Published: September 2011

AbstractThe title derivatives (IV) and (VI) are prepared by a one‐pot reaction between an aromatic aldehyde, indolylethanone, malononitrile, and ammonium acetate.
ChemInform Abstract: Buchwald Reaction as the Key Step for the Synthesis of Metabolically More Stable Analogues of Amodiaquine.
Authors: Le Fur Nicolas , Hochart Guillaume , Larchanche Paul‐Emmanuel , Melnyk Patricia 
Published: September 2011

AbstractTarget compounds (IX) are synthesized via key intermediates (VI) using a super‐electrophilic amidomethylation, cf.
ChemInform Abstract: Synthesis and Antibacterial Activity of Isochromene and Isoquinoline Derivative.
Authors: Dabholkar Vijay V. , Tripathi Dilip R. 
Published: September 2011

AbstractNovel thiazolylisochromene derivative (VII) is synthesized by reaction of benzoic acid (V) with benzoin, and transformed into corresponding isoquinoline derivatives (IX).
ChemInform Abstract: Synthesis and Anticonvulsant Activity of 7‐Phenyl‐6,7‐dihydro‐[1,2,4]triazolo[1,5‐a]pyrimidin‐5(4H)‐ones and their Derivatives.
Authors: Deng Xian‐Qing , Quan Li‐Na , Song Ming‐Xia , Wei Cheng‐Xi , Quan Zhe‐Shan 
Published: September 2011

AbstractCyclization of methyl cinnamates (I) with triazolamine (II), pyrazolamine (VI), aminoimidazole (VIII), and benzoimidazolamine (X), affords the corresponding fused compounds in low to sufficient yields.
ChemInform Abstract: Synthesis and Structure of Novel (S)‐1,6‐Dialkylpiperazine‐2,5‐diones and (3S,6S)‐1,3,6‐Trialkylpiperazine‐2,5‐diones.
Authors: Malavasic Crt , Groselj Uros , Golobic Amalija , Bezensek Jure , Stanovnik Branko , Stare Katarina , Wagger Jernej , Svete Jurij 
Published: September 2011

AbstractThe dialkylpiperazines are prepared from α‐amino acid ester hydrochlorides in three steps.
ChemInform Abstract: Highly Selective Methods for Synthesis of Internal (α‐) Vinylboronates Through Efficient NHC—Cu‐Catalyzed Hydroboration of Terminal Alkynes. Utility in Chemical Synthesis and Mechanistic Basis for Selectivity.
Authors: Jang Hwanjong , Zhugralin Adil R. , Lee Yunmi , Hoveyda Amir H. 
Published: September 2011

AbstractTerminal aliphatic or aromatic alkynes can easily undergo hydroboration in the presence of NHC—Cu complexes.
ChemInform Abstract: Synthesis of Conformationally Modified Peptides Through Isonitrile Chemistry: Implications for Dealing with Polypeptide Aggregation.
Authors: Wu Xiangyang , Park Peter K. , Danishefsky Samuel J. 
Published: September 2011

AbstractA method is presented for the introduction of a dimethyleneoxy bridge spanning the amide functionalities of two consecutive amino acids such as shown for (VII).
ChemInform Abstract: Synthetic Studies on Natural Products. Part 39. Total Synthesis of Racemic and (R)‐ and (S)‐4‐Methoxyalkanoic Acids and Their Antifungal Activity.
Authors: Das Biswanath , Shinde Digambar Balaji , Kanth Boddu Shashi , Kamle Avijeet , Kumar C. Ganesh 
Published: September 2011

AbstractMethoxydecanoic acid (VIIa) and methoxyundecanoic acid (VIIb) are synthesized both in racemic and stereoselective form.
ChemInform Abstract: Synthesis and Evaluation of Monoamidoxime Derivatives: Toward New Antileishmanial Compounds.
Authors: Paloque Lucie , Bouhlel Ahlem , Curti Christophe , Dumetre Aurelien , Verhaeghe Pierre , Azas Nadine , Vanelle Patrice 
Published: September 2011

AbstractPerforming manganese(III)‐ and microwave‐assisted reactions enable the synthesis of a new series of monoamidoximes.
ChemInform Abstract: Sasa quelpaertensis Phenylpropanoid Derivative Suppresses Lipopolysaccharide‐Induced Nitric Oxide Synthase and Cyclo‐oxygenase‐2 Expressions in RAW 264.7 Cells
Authors: Moon Ji‐Young , Yang Eun‐Jin , Kim Sang Suk , Kang Ji‐Yong , Kim Gi‐Ok , Lee Nam Ho , Hyun Chang‐Gu 
Published: September 2011

AbstractReview: 32 refs.
Analysis of energy dissipation in stirred suspension polymerisation reactors using computational fluid dynamics
Authors: Nogueira E. S. , Pinto J. C. , Vianna A. S. 
Published: September 2011

AbstractThis work evaluates the spatial distribution of normalised rates of droplet breakage and droplet coalescence in liquid–liquid dispersions maintained in agitated tanks at operation conditions normally used to perform suspension polymerisation reactions. Particularly, simulations are performed with multiphase computational fluid dynamics (CFD) models to represent the flow field in liquid–liquid styrene suspension polymerisation reactors for the first time. CFD tools are used first to compute the spatial distribution of the turbulent energy dissipation rates (ε) inside the reaction vessel; afterwards, normalised rates of droplet breakage and particle coalescence are computed as functions of ε. Surprisingly, multiphase simulations showed that the rates of energy dissipation can be very high near the free vortex surfaces, which has been completely neglected in previous works. The obtained results indicate the existence of extremely large energy dissipation gradients inside the vessel, so that particle breakage occurs primarily in very small regions that surround the impeller and the free vortex surface, while particle coalescence takes place in the liquid bulk. As a consequence, particle breakage should be regarded as an independent source term or a boundary phenomenon. Based on the obtained results, it can be very difficult to justify the use of isotropic assumptions to formulate particle population balances in similar systems, even when multiple compartment models are used to describe the fluid dynamic behaviour of the agitated vessel. © 2011 Canadian Society for Chemical Engineering
Impact of residual normal metaphases in core binding factor acute myeloid leukemia
Authors: Medeiros Bruno C. , Othus Megan , Fang Min , Appelbaum Frederick R. , Estey Elihu H. 
Published: September 2011

AbstractBACKGROUND:Karyotype allows for stratification of outcomes in acute myeloid leukemia (AML) patients. Previous data suggested that the presence of residual normal cells improved the prognosis in patients with monosomy 7. The Southwest Oncology Group (SWOG) reported the impact of residual normal metaphases in AML patients with monosomal karyotype (MK) and found a similar relationship. We determined the influence of residual normal metaphases in patients with core binding factor (CBF) AML.METHODS:The presence and total number of normal and abnormal metaphases were tallied for patients with CBF AML treated in 10 consecutive SWOG trials and used as a variable to determine the effect on complete remission, refractory disease, and overall survival (OS) rates.RESULTS:Among 113 CBF AML patients, median age of diagnosis was 45 years (range, 18‐77 years), and median OS was 4 years (CI—2 years—not reached). Patients with inv(16) and no normal metaphases had improved OS compared with those with 1+ normal metaphases (P = .00005), whereas no difference was noted for patients with t(8;21). Multivariate analysis demonstrated that having cells with a normal karyotype had a negative impact on survival (HR, 2.11; 95% CI, 1.09‐4.08; P = .026). This shorter survival was a consequence of a higher rate of refractory disease in older patients (OR, 1.03; 95% CI, 0.9998‐1.06; P = .05) and in those with normal metaphases (HR, 1.26 95% CI, 1.04‐1.51; P = .02).CONCLUSIONS:In patients with CBF AML, the presence of cells with normal metaphases and increasing age negatively affect the prognosis, especially in patients with inv(16). Cancer 2012;. © 2011 American Cancer Society.
Metabolism, Temperature, and Ventilation
Authors: Mortola Jacopo P. , Maskrey Michael 
Published: September 2011

AbstractIn mammals and birds, all oxygen used (o2) must pass through the lungs; hence, some degree of coupling betweeno2and pulmonary ventilation (e) is highly predictable. Nevertheless,eis also involved with CO2elimination, a task that is often in conflict with the convection of O2. In hot or cold conditions, the relationship betweeneando2includes the participation of the respiratory apparatus to the control of body temperature and water balance. Some compromise among these tasks is achieved through changes in breathing pattern, uncoupling changes in alveolar ventilation frome. This article examines primarily the relationship betweeneando2under thermal stimuli. In the process, it considers how the relationship is influenced by hypoxia, hypercapnia or changes in metabolic level. The shuffling of tasks in emergency situations illustrates that the constraints one‐o2for the protection of blood gases have ample room for flexibility. However, when other priorities do not interfere with the primary goal of gas exchange,efollows metabolic rate quite closely. The fact that arterial CO2remains stable when metabolism is changed by the most diverse circumstances (moderate exercise, cold, cold and exercise combined, variations in body size, caloric intake, age, time of the day, hormones, drugs, etc.) makes it unlikely thateand metabolism are controlled in parallel by the condition responsible for the metabolic change. Rather, some observations support the view that the gaseous component of metabolic rate, probably CO2, may provide the link between the metabolic level ande. © 2011 American Physiological Society.Compr Physiol1:1679‐1709, 2011.
Expiratory Flow Limitation
Authors: Pedersen Ole F. , Butler James P. 
Published: September 2011

AbstractExpiratory flow limitation occurs when flow ceases to increase with increasing expiratory effort. The equal pressure point concept has been largely successful in providing intuitive understanding of the phenomenon, wherein maximal flows are determined by lung recoil and resistance upstream of the site where bronchial transmural pressure is zero (the EPP). Subsequent work on the fluid dynamical foundations led to the wave‐speed theory of flow limitation, where flow is limited at a site when the local gas velocity is equal to speed of propagation of pressure waves. Each is a local theory; full predictions require knowledge of both density‐dependent Bernoulli pressure drops and viscosity‐dependent pressure losses due to dissipation. The former is dominant at mid to high lung volumes, whereas the latter is more important at low lung volumes as the flow‐limiting site moves peripherally. The observation of relative effort independence of the maximal flow versus volume curves is important clinically insofar as such maneuvers, when carefully performed, offer a unique window into the mechanics of the lung itself, with little confounding effects. In particular, the important contributions of lung recoil and airways resistance can often be assessed, with implications and applications to diagnosis and management of pulmonary disease. © 2011 American Physiological Society.Compr Physiol1:1861‐1882, 2011.
Neuronal Control of Breathing: Sex and Stress Hormones
Authors: Behan Mary , Kinkead Richard 
Published: September 2011

AbstractThere is a growing public awareness that hormones can have a significant impact on most biological systems, including the control of breathing. This review will focus on the actions of two broad classes of hormones on the neuronal control of breathing: sex hormones and stress hormones. The majority of these hormones are steroids; a striking feature is that both groups are derived from cholesterol. Stress hormones also include many peptides which are produced primarily within the paraventricular nucleus of the hypothalamus (PVN) and secreted into the brain or into the circulatory system. In this article we will first review and discuss the role of sex hormones in respiratory control throughout life, emphasizing how natural fluctuations in hormones are reflected in ventilatory metrics and how disruption of their endogenous cycle can predispose to respiratory disease. These effects may be mediated directly by sex hormone receptors or indirectly by neurotransmitter systems. Next, we will discuss the origins of hypothalamic stress hormones and their relationship with the respiratory control system. This relationship is 2‐fold: (i)viadirect anatomical connections to brainstem respiratory control centers, and (ii)viasteroid hormones released from the adrenal gland in response to signals from the pituitary gland. Finally, the impact of stress on the development of neural circuits involved in breathing is evaluated in animal models, and the consequences of early stress on respiratory health and disease is discussed. © 2011 American Physiological Society.Compr Physiol1:2101‐2139, 2011.
Inflammatory Mechanisms in the Pathogenesis of Pulmonary Arterial Hypertension
Authors: Chami Hala El , Hassoun Paul M. 
Published: September 2011

AbstractInflammation is a prominent feature of human and experimental pulmonary hypertension (PH) as suggested by infiltration of various inflammatory cells and increased expression of certain cytokines in remodeled pulmonary vessels. Macrophages, T and B lymphocytes, and dendritic cells are found in the vascular lesions of idiopathic pulmonary arterial hypertension (PAH) as well as in PAH associated with connective tissue diseases or infectious etiologies such as HIV. In addition, PAH is often characterized by the presence of circulating chemokines and cytokines, increased expression of growth (such as VEGF and PDGF) and transcriptional (e.g., nuclear factor of activated T cells or NFAT) factors, and viral protein components (e.g., HIV‐1Nef), which directly contribute to further recruitment of inflammatory cells and the pulmonary vascular remodeling process. These inflammatory pathways may thus serve as potential specific therapeutic targets. This article provides an overview of inflammatory pathways involving chemokines and cytokines as well as growth factors, highlighting their potential role in pulmonary vascular remodeling and the possibility of future targeted therapy. © 2011 American Physiological Society.Compr Physiol1:1929‐1941, 2011.