bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical training prevents oxidative stress in L‐NAME‐induced hypertension rats
Authors: Cardoso Andréia Machado , Martins Caroline Curry , Fiorin Fernando da Silva , Schmatz Roberta , Abdalla Fátima Husein , Gutierres Jessié , Zanini Daniela , Fiorenza Amanda Maino , Stefanello Naiara , Serres Jonas Daci da Silva , Carvalho Fabiano , Castro Verônica Paiva , Mazzanti Cinthia Melazzo , Royes Luiz Fernando Freire , Belló‐Klein Adriane , Goularte Jeferson Ferraz , Morsch Vera Maria , Bagatini Margarete Dulce , Schetinger Maria Rosa Chitolina
Published: September 2012

The present study investigated the effects of a 6‐week swimming training on blood pressure, nitric oxide (NO) levels and oxidative stress parameters such as protein and lipid oxidation, antioxidant enzyme activity and endogenous non‐enzymatic antioxidant content in kidney and circulating fluids, as well as on serum biochemical parameters (cholesterol, triglycerides, urea and creatinine) from Nω‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME)‐induced hypertension treated rats. Animals were divided into four groups (n = 10): Control, Exercise, L‐NAME and Exercise L‐NAME. Results showed that exercise prevented a decrease in NO levels in hypertensive rats (P < 0·05). An increase in protein and lipid oxidation observed in the L‐NAME‐treated group was reverted by physical training in serum from the Exercise L‐NAME group (P < 0·05). A decrease in the catalase (CAT) and superoxide dismutase (SOD) activities in the L‐NAME group was observed when compared with normotensive groups (P < 0·05). In kidney, exercise significantly augmented the CAT and SOD activities in the Exercise L‐NAME group when compared with the L‐NAME group (P < 0·05). There was a decrease in the non‐protein thiols (NPSH) levels in the L‐NAME‐treated group when compared with the normotensive groups (P < 0·05). In the Exercise L‐NAME group, there was an increase in NPSH levels when compared with the L‐NAME group (P < 0·05). The elevation in serum cholesterol, triglycerides, urea and creatinine levels observed in the L‐NAME group were reverted to levels close to normal by exercise in the Exercise L‐NAME group (P < 0·05). Exercise training had hypotensive effect, reducing blood pressure in the Exercise L‐NAME group (P < 0·05). These findings suggest that physical training could have a protector effect against oxidative damage and renal injury caused by hypertension. Copyright © 2012 John Wiley & Sons, Ltd.
NMR Studies of HAR1 RNA Secondary Structures Reveal Conformational Dynamics in the Human RNA
Authors: Ziegeler Melanie , Cevec Mirko , Richter Christian , Schwalbe Harald
Published: September 2012

Comparative genomics has shown that noncoding RNAs can display substantial differences between humans and chimpanzees. The human accelerated region 1 (HAR1) is a section in the human genome that exhibits the most strongly accelerated rate of nucleotide substitution in relation to the chimpanzee genome. It is associated with higher cognitive functions in human brains. The HAR1 region of the HAR1F gene is transcribed into a 118 nt noncoding RNA. We provide experimental data to validate available secondary structure models of chimpanzee and human HAR1 RNA by utilizing CD and NMR spectroscopy and applying a “divide‐and‐conquer” strategy. The mutations lead to more dynamic secondary and tertiary structure in the human HAR1 RNA, presumably as part of its function. We have also determined NMR solution structures of helix H1 as the most conserved part of the chimpanzee and human HAR1 RNAs. Helix H1 contains a GAA asymmetric internal loop, the structure of which had not been solved previously. 37 nt chimpanzee and human RNA fragments (c37 and h37 RNAs) differ in a single base pair. h37 RNA folds into a slightly more stable and rigid structure than c37 RNA. Both NMR structures show structural heterogeneity of the residues corresponding to the GAA loop.
Genome Mining of the Biosynthetic Gene Cluster of the Polyene Macrolide Antibiotic Tetramycin and Characterization of a P450 Monooxygenase Involved in the Hydroxylation of the Tetramycin B Polyol Segment
Authors: Cao Bo , Yao Fen , Zheng Xiaoqing , Cui Dongbing , Shao Yucheng , Zhu Changxiong , Deng Zixin , You Delin
Published: September 2012

A polyene macrolide antibiotic tetramycin biosynthetic gene cluster was identified by genome mining and isolated from Streptomyces hygrospinosus var. beijingensis. Genetic and in silico analyses gave insights into the mechanism of biosynthesis of tetramycin, and a model of the tetramycin biosynthetic pathway is proposed. Inactivation of a cytochrome P450 monooxygenase gene, tetrK, resulted in the production of a tetramycin B precursor: tetramycin A, which lacks a hydroxy group in its polyol region. TetrK was subsequently overexpressed heterologously in E. coli with a His6 tag, and purified TetrK efficiently hydroxylated tetramycin A to afford tetramycin B. Kinetic studies revealed no inhibition of TetrK by substrate or product. Surprisingly, sequence‐alignment analysis showed that TetrK, as a hydroxylase, has much higher homology with epoxidase PimD than with hydroxylases NysL and AmphL. The 3D structure of TetrK was then constructed by homology modeling with PimD as reference. Although TetrK and PimD catalyzed different chemical reactions, homology modeling indicated that they might share the same catalytic sites, despite also possessing some different sites correlated with substrate binding and substrate specificity. These findings offer good prospects for the production of improved antifungal polyene analogues.
Sulfite Action in Glycolytic Inhibition: In Vivo Real‐Time Observation by Hyperpolarized 13C NMR Spectroscopy
Authors: Meier Sebastian , Solodovnikova Natalia , Jensen Pernille R. , Wendland Jürgen
Published: September 2012

Detecting the molecular targets of xenobiotic substances in vivo poses a considerable analytical challenge. Here, we describe the use of an NMR‐based tracer methodology for the instantaneous in vivo observation of sulfur(IV) action on cellular metabolism. Specifically, we find that glycolytic flux is directed towards sulfite adducts of dihydroxyacetone phosphate and pyruvate as off‐pathway intermediates that obstruct glycolytic flux. In particular, the pyruvate–sulfite association hinders the formation of downstream metabolites. The apparent in vivo association constant of pyruvate and sulfite agrees with the apparent inhibition constant of CO2 formation, thus supporting the importance of pyruvate interception in disturbing central metabolism and inhibiting NAD regeneration.
From an Icosahedron to a Plane: Flattening Dodecaiodo‐dodecaborate by Successive Stripping of Iodine
Authors: Farràs Pau , Vankova Nina , Zeonjuk Lei Liu , Warneke Jonas , Dülcks Thomas , Heine Thomas , Viñas Clara , Teixidor Francesc , Gabel Detlef
Published: September 2012

It has been shown by electrospray ionization–ion‐trap mass spectrometry that B12I122− converts to an intact B12 cluster as a result of successive stripping of single iodine radicals or ions. Herein, the structure and stability of all intermediate B12In− species (n=11 to 1) determined by means of first‐principles calculations are reported. The initial predominant loss of an iodine radical occurs most probably via the triplet state of B12I122−, and the reaction path for loss of an iodide ion from the singlet state crosses that from the triplet state. Experimentally, the boron clusters resulting from B12I122− through loss of either iodide or iodine occur at the same excitation energy in the ion trap. It is shown that the icosahedral B12 unit commonly observed in dodecaborate compounds is destabilized while losing iodine. The boron framework opens to nonicosahedral structures with five to seven iodine atoms left. The temperature of the ions has a considerable influence on the relative stability near the opening of the clusters. The most stable structures with five to seven iodine atoms are neither planar nor icosahedral.
Protonation of an Oxo‐Bridged Diiron Unit Gives Two Different Iron Centers: Synthesis and Structure of a New Class of Diiron(III)‐μ‐hydroxo Bisporphyrins and the Control of Spin States by Using Counterions
Authors: Bhowmik Susovan , Ghosh Sudip Kumar , Layek Samar , Verma Harish Chandra , Rath Sankar Prasad
Published: September 2012

Reported herein is a hitherto unknown family of diiron(III)‐μ‐hydroxo bisporphyrins in which two different spin states of Fe are stabilized in a single molecular framework, although both cores have identical molecular structures. Protonation of the oxo‐bridged dimer (2) by using strong Brønsted acids, such as HI, HBF4, and HClO4, produce red μ‐hydroxo complexes with I3− (3), BF4− (4), and ClO4− (5) counterions, respectively. The X‐ray structure of the molecule reveals that the FeO bond length increases on going from the μ‐oxo to the hydroxo complex, whereas the Fe‐O(H)‐Fe unit becomes more bent, which results in the smallest known Fe‐O(H)‐Fe angles of 142.5(2) and 141.2(1)° for 3 and 5, respectively. In contrast, the Fe‐O(H)‐Fe angle remains unaltered in 4 from the corresponding μ‐oxo complex. The close approach of two rings in a molecule results in unequal core deformations in 3 and 4, whereas the cores are deformed almost equally but to a lesser extent in 5. Although 3 was found to have nearly high‐spin and admixed intermediate Fe spin states in cores I and II, respectively, two admixed intermediate spin states were observed in 4. Even though the cores have identical chemical structures, crucial bond parameters, such as the FeNp, FeO, and Fe⋅⋅⋅Ctp bond lengths and the ring deformations, are all different between the two FeIII centers in 3 and 4, which leads to an eventual stabilization of two different spin states of Fe in each molecule. In contrast, the two Fe centers in 5 are equivalent and assigned to high and intermediate spin states in the solid and solution states, respectively. The spin states are thus found to be dependent on the counterions and can also be reversibly interconverted. Upon protonation, the strong antiferromagnetic coupling in the μ‐oxo dimer (J, −126.6 cm−1) is attenuated to almost zero in the μ‐hydroxo complex with the I3− counterion, whereas the values of J are −36 and −42 cm−1, respectively, for complexes with BF4− and ClO4− counterions.
ChemInform Abstract: The Complex Metal‐Rich Boride Ti1+xRh2‐x+yIr3‐yB3 (x = 0.68, y = 1.06) with a New Structure Type Containing B4 Zigzag Fragments: Synthesis, Crystal Chemistry and Theoretical Calculations.
Authors: Goerens Christian , Fokwa Boniface P. T.
Published: September 2012

Ti1.68Rh2.38Ir1.94B3 is prepared by arc‐melting of the elements and characterized by single crystal XRD and DFT calculations.
ChemInform Abstract: Crystal Structure of Sr6Y2Al4O15: XRD Refinements and First‐Principle Calculations.
Authors: Wang Chun‐Hai , Guo Dong‐Fang , Li Zhao‐Fei , Wang Xiao‐Ming , Lin Jian‐Hua , Zeng Zheng‐Zhi , Jing Xi‐Ping
Published: September 2012

The compounds Sr6Ln2Al4O15 (Ln: Y, Tb, Dy, Ho, Er, Tm, Yb, Lu) are prepared by solid state reactions of stoichiometric amounts of SrCO3, Ln2O3, and Al2O3 (alumina crucibles, 1500 °C, 12 h).
ChemInform Abstract: Phase Diagrams of the Tb—Ag—In and Dy—Ag—In Systems at 870 K.
Authors: Demchyna M. , Belan B. , Manyako M. , Pietraszko A. , Kalychak Ya.
Published: September 2012

The phase equilibria of the title systems at 870 K are characterized by powder and single crystal XRD.
ChemInform Abstract: α‐Sulfur Crystals as a Visible‐Light‐Active Photocatalyst.
Authors: Liu Gang , Niu Ping , Yin Lichang , Cheng Hui‐Ming
Published: September 2012

α‐Sulfur (S8) is characterized by DFT electronic structure calculations, XRD, XPS, fluorescence and UV/VIS spectroscopy, and by photocatalytic and photoelectrochemical measurements.
ChemInform Abstract: [(C4N2H12) 3·H2O] [(Al2P3O12)2]: A New Anionic Open‐Framework Aluminophosphate with Helical Chains and Multi‐Directional Intersecting Twelve‐Ring Channels.
Authors: Tong Xiaoqiang , Huang Pai , Lu Huiying , Yan Wenfu , Yu Jihong , Xu Ruren
Published: September 2012

The new title compound is hydrothermally synthesized from an aqueous mixture of Al2O3, H3PO4, and piperazine (autoclave, 180 °C, 3 d) and its structure is determined by single crystal XRD.
ChemInform Abstract: Synthesis, Structure, and Electrical Resistivity of Cs3U18Se38.
Authors: Oh George N. , Ibers James A.
Published: September 2012

The title compound is synthesized by solid state reaction of U, Se, CsCl or Cs2Se3, and P or As (1273 K for 4 h, 1223 K for 96 h, 1073 K for 96 h, 5 wt.% yield).
ChemInform Abstract: Syntheses and Structure of Hydrothermally Prepared CsNiX3 (X: Cl, Br, I).
Authors: Raw Adam D. , Ibers James A. , Poeppelmeier Kenneth R.
Published: September 2012

Single crystals of the title compounds are prepared by hydrothermal reaction of NiX2 (X: Cl, Br, I), CsOH, and 85% aq.
ChemInform Abstract: Synthesis of Enantioenriched Tertiary Boronic Esters from Secondary Allylic Carbamates. Application to the Synthesis of C30 Botryococcene.
Authors: Pulis Alexander P. , Aggarwal Varinder K.
Published: September 2012

The reaction of lithiated allylic carbamates with boronic esters proceeds with excellent α‐selectivity and retention of stereochemistry.
ChemInform Abstract: Undirected Arene and Chelate‐Assisted Olefin C—H Bond Activation: [RhIIICp*]‐Catalyzed Dehydrogenative Alkene—Arene Coupling as a New Pathway for the Selective Synthesis of Highly Substituted Z Olefins.
Authors: Wencel‐Delord Joanna , Nimphius Corinna , Patureau Frederic W. , Glorius Frank
Published: September 2012

Reaction of vinylic substrates (I) with bromobenzene gives a mixture of meta‐ and para‐substituted Z‐olefins [cf.
ChemInform Abstract: Palladium‐Catalyzed Substitution and Cross‐Coupling of Benzylic Fluorides.
Authors: Blessley George , Holden Patrick , Walker Matthew , Brown John M. , Gouverneur Veronique
Published: September 2012

A variety of benzyl fluorides is applied in the reactions using carbon, nitrogen, oxygen or sulfur nucleophiles.
ChemInform Abstract: Asymmetric Calcium Catalysis: Highly Enantioselective Carbonyl‐Ene and Friedel—Crafts Reactions for the Synthesis of Quaternary α‐Hydroxy Esters Bearing a Trifluoromethyl Group.
Authors: Rueping Magnus , Bootwicha Teerawut , Kambutong Supakeat , Sugiono Erli
Published: September 2012

First enantioselective calcium‐catalyzed addition reaction of trifluoropyruvate (III) with various styrene derivatives (II) provides α‐hydroxy‐α‐trifluoromethyl esters (IV) in good yields and high enantioselectivities at low catalyst loading.
ChemInform Abstract: Iron(III) Chloride Catalyzed Aerobic Reduction of Olefins Using Aqueous Hydrazine at Ambient Temperature.
Authors: Lamani Manjunath , Ravikumara Guralamata S. , Prabhu Kandikere Ramaiah
Published: September 2012

A chemoselective reduction reaction is applied to a variety of terminal and internal alkenes and a terminal alkyne.
ChemInform Abstract: Efficient Procedures to Prepare Primary and Secondary Alkyl Halides from Alkanols via the Corresponding Sulfonates under Mild Conditions.
Authors: Cahiez Gerard , Gager Olivier , Moyeux Alban , Delacroix Thomas
Published: September 2012

A wide range of tosylates, methyl‐ or phenylsulfonates is easily converted using lithium halides as a halogen source and THF as a solvent.
ChemInform Abstract: Acetohydroxamic Acid: A New Reagent for Efficient Synthesis of Nitriles Directly from Aldehydes Using Bi(O‐Tf)3 as the Catalyst.
Authors: Sridhar Madabhushi , Reddy Mallu Kishore Kumar , Sairam Vangipuram Venkata , Raveendra Jillella , Godala Kondal Reddy , Narsaiah Chinthala , Ramanaiah Beeram China , Reddy Cirandur Suresh
Published: September 2012

Treatment of aldehydes according to A) results in formation of nitriles via an aldoxime intermediate.
ChemInform Abstract: Diastereo‐ and Enantioselective Synthesis of (E)‐2‐Methyl‐1,2‐syn‐ and (E)‐2‐Methyl‐1,2‐anti‐3‐pentenediols via Allenylboronate Kinetic Resolution with (dlpc)2BH and Aldehyde Allylboration.
Authors: Han Jeng‐Liang , Chen Ming , Roush William R.
Published: September 2012

It provides an efficient approach to enantioenriched 1,2‐syn‐ and 1,2‐anti‐pentenediols.
ChemInform Abstract: Halodiazophosphonates, a New Class of Diazo Compounds for the Diastereoselective Intermolecular Rh(II) Catalyzed Cyclopropanation.
Authors: Schnaars Christian , Hansen Tore
Published: September 2012

Generation of the title compounds and their cyclopropanation with styrenes proceeds in one pot to afford the cyclopropane derivatives with high diastereoselectivity.
ChemInform Abstract: Synthesis of Dispiro[2.1.3.1]nonane (VIII) and Trispiro[2.1.1.37.15.13]dodecane (VI)
Authors: Molchanov A. P. , Kostikov R. R.
Published: September 2012

starting from ester (I)
ChemInform Abstract: Electrophilic Trifluoromethylation by Copper‐Catalyzed Addition of CF3‐Transfer Reagents to Alkenes and Alkynes.
Authors: Janson Paer G. , Ghoneim Ibrahim , Ilchenko Nadia O. , Szabo Kalman J.
Published: September 2012

The reaction of the hypervalent iodine reagent (I) with alkynes proceeds with complete stereoselectivity.
ChemInform Abstract: Highly Stereoselective Synthesis of (Z)‐1,2‐Dihaloalkenes by a Pd‐Catalyzed Hydrohalogenation of Alkynyl Halides.
Authors: Zhu Gangguo , Chen Dongxu , Wang Yuyi , Zheng Renwei
Published: September 2012

The obtained products are suitable for subsequent reactions such as Sonogashira couplings or Diels—Alder cyclizations.
ChemInform Abstract: Enantio‐ and Diastereoselective Michael Addition Reactions of α‐Cyanoketones to Nitroalkenes Catalyzed by Binaphthyl‐Derived Organocatalyst.
Authors: Lee Hyun Joo , Woo Saet Byeol , Kim Dae Young
Published: September 2012

The use of catalyst (I) provides the corresponding γ‐nitro α‐cyanoketones with excellent diastereo‐ and enantioselectivity.
ChemInform Abstract: Synthesis of Symmetric 1,4‐Diamino‐2‐butynes via a Cu(I)‐Catalyzed One‐Pot A3‐Coupling/Decarboxylative Coupling of a Propiolic Acid, an Aldehyde, and an Amine.
Authors: Feng Huangdi , Ermolat'ev Denis S. , Song Gonghua , Van der Eycken Erik V.
Published: September 2012

The target compounds are obtained as diastereomeric mixtures, inseparable by chromatography and spectroscopy.
ChemInform Abstract: Organophosphorus‐Catalyzed Staudinger Reduction.
Authors: van Kalkeren Henri A. , Bruins Jorick J. , Rutjes Floris P. J. T. , van Delft Floris L.
Published: September 2012

A wide range of electron‐poor and electron‐rich aryl azides is converted to anilines.
ChemInform Abstract: CuI/DMPAO‐Catalyzed N‐Arylation of Acyclic Secondary Amines.
Authors: Zhang Yu , Yang Xinye , Yao Qizheng , Ma Dawei
Published: September 2012

It is found that CuI/DMPAO efficiently promotes the N‐arylation of acyclic secondary amines.
ChemInform Abstract: Ruthenium(II)‐Catalyzed Synthesis of Hydroxylated Arenes with Ester as an Effective Directing Group.
Authors: Yang Yiqing , Lin Yun , Rao Yu
Published: September 2012

K2S2O8, iodic acid or Selectfluor can be used as oxidants to afford ortho‐hydroxylated benzoates selectively.
ChemInform Abstract: Organocatalytic Dakin Oxidation by Nucleophilic Flavin Catalysts.
Authors: Chen Shuai , Hossain Mohammad S. , Foss Frank W. Jr.
Published: September 2012

Electron‐rich arylaldehydes are effectively converted to phenols using the flavin catalysts (I).
ChemInform Abstract: An Iron Catalyzed Regioselective Oxidation of Terminal Alkenes to Aldehydes.
Authors: Chowdhury Abhishek Dutta , Ray Ritwika , Lahiri Goutam Kumar
Published: September 2012

The mild and benign title reaction for anti‐Markovnikov oxidation is developed by using an abundant, cheap, and simple catalyst.
ChemInform Abstract: An Unprecedented Ring‐Opening Reaction of N‐(Aziridin‐2‐ylmethylene)hydrazines to Facile Synthesis of Functionalized Enamines Catalyzed by Lewis Acid.
Authors: Zhang Zhen , Wei Yin , Shi Min
Published: September 2012

In the mild ring‐opening, the anchimeric assistance of the anchored hydrazone moiety is proposed.
ChemInform Abstract: Synthesis of α‐Hydroxyacetophenones.
Authors: McLaughlin Mark , Belyk Kevin M. , Qian Gang , Reamer Robert A. , Chen Cheng‐yi
Published: September 2012

The acidic hydrolysis proceeds with minimal formation of polymeric by‐products and affords the important synthetic intermediates with good yields.
ChemInform Abstract: Ru‐Catalyzed Highly Chemo‐ and Enantioselective Hydrogenation of γ‐Halo‐γ,δ‐unsaturated‐β‐keto Esters under Neutral Conditions.
Authors: Ma Xin , Li Wanfang , Li Xiaoming , Tao Xiaoming , Fan Weizheng , Xie Xiaomin , Ayad Tahar , Ratovelomanana‐Vidal Virginie , Zhang Zhaoguo
Published: September 2012

The reaction of the compound (Id) also gives traces of debrominated by‐product.
ChemInform Abstract: Iron‐Catalyzed Efficient Synthesis of Amides from Aldehydes and Amine Hydrochloride Salts.
Authors: Ghosh Subhash Chandra , Ngiam Joyce S. Y. , Chai Christina L. L. , Seayad Abdul M. , Dang Tuan Thanh , Chen Anqi
Published: September 2012

The reaction is applied to a wide range or primary and secondary amines hydrochlorides or aromatic and aliphatic aldehydes.
ChemInform Abstract: Tetraethylammonium 2‐(N‐Hydroxycarbamoyl)benzoate: A Powerful Bifunctional Metal‐Free Catalyst for Efficient and Rapid Cyanosilylation of Carbonyl Compounds under Mild Conditions.
Authors: Dekamin Mohammad G. , Karimi Zhara , Farahmand Mehdi
Published: September 2012

The new catalyst, which is prepared from inexpensive precursors, is successfully applied to the title reaction which includes an easy work‐up.
ChemInform Abstract: NCP Pincer Palladacycle as a Phosphine‐Free Catalyst Precursor for the Heck—Mizoroki Coupling of Aryl Halides.
Authors: Rosa Gilber R. , Rosa Diego S.
Published: September 2012

The NCP pincer palladacycle complex efficiently catalyzes the Heck reaction of various aryl iodides (II) and bromides (IV) with butyl acrylate (I).
ChemInform Abstract: Inside‐Out Core—Shell Architecture: Controllable Fabrication of Cu2O@Cu with High Activity for the Sonogashira Coupling Reaction.
Authors: Kou Jiahui , Saha Amit , Bennett‐Stamper Christina , Varma Rajender S.
Published: September 2012

The applied catalyst is easily prepared from copper chloride and consists of a Cu2O core and a Cu shell which is in contrast to the generally reported Cu2O‐outside structure.
ChemInform Abstract: Rhodium(I)‐Catalyzed Domino Asymmetric Ring Opening/Enantioselective Isomerization of Oxabicyclic Alkenes with Water.
Authors: Tsui Gavin C. , Lautens Mark
Published: September 2012

Chiral trans‐1,2‐diols are synthesized in one step with good yields and excellent enantioselectivity under mild conditions.
ChemInform Abstract: Carbon—Carbon Bond Formation via the Electrophilic Addition of Carbocations to Allenes.
Authors: Meng Bo , Ma Shengming
Published: September 2012

1,1‐Disubstituted allenes react with 1,3‐diarylprop‐2‐en‐1‐ols in the presence of ZnCl2 to afford indenes.
ChemInform Abstract: Palladium‐Catalyzed Arylation of Methylene‐Bridged Polyarenes: Synthesis and Structures of 9‐Arylfluorene Derivatives.
Authors: Chen Jheng‐Jhih , Onogi Satoru , Hsieh Ya‐Chu , Hsiao Chien‐Chi , Higashibayashi Shuhei , Sakurai Hidehiro , Wu Yao‐Ting
Published: September 2012

The reaction of fluorene (I) with various aromatic bromides and chlorides affords arylated products, mostly as mixtures of rotamers.
ChemInform Abstract: Synthesis of Highly Functionalized 9,10‐Phenanthrenequinones by Oxidative Coupling Using MoCl5.
Authors: Trosien Simon , Waldvogel Siegfried R.
Published: September 2012

An efficient method to prepare functionalized 9,10‐phenanthrenequinones including the natural cypripediquinone A (VIIIa) is reported.
ChemInform Abstract: Chiral Phosphoric Acid‐Catalyzed Enantioselective and Diastereoselective Spiroketalizations.
Authors: Sun Zhankui , Winschel Grace A. , Borovika Alina , Nagorny Pavel
Published: September 2012

The axially chiral BINOL‐derived phosphoric acid TRIP is an efficient catalyst for highly enantio‐ or diastereoselective cyclization reactions of various achiral and chiral cyclic enol ethers to give nonthermodynamic spiroketals.
ChemInform Abstract: Furan Ring Opening—Indole Ring Closure: SnCl2‐Induced Reductive Transformation of Difuryl(2‐nitroaryl)methanes into 2‐(2‐Acylvinyl)indoles.
Authors: Uchuskin Maxim G. , Molodtsova Natalia V. , Abaev Vladimir T. , Trushkov Igor V. , Butin Alexander V.
Published: September 2012

The reaction proceeds via reductive furan ring opening followed by indole ring closure.
ChemInform Abstract: Atom‐Economical Synthesis of the Functionalized Spirocyclic Oxindole‐Butenolide via Three‐Component [2 + 2 + 1] Cycloaddition Strategy.
Authors: Li Jian , Liu Yuejin , Li Chunju , Jie Haohua , Jia Xueshun
Published: September 2012

The [2 + 2 + 1] multicomponent cycloaddition of isatins (I), alkynes (II), and isocyanides (III) yields the desired spirocyclic oxindole‐butenolides (IV).
ChemInform Abstract: Multicomponent Domino Reactions of Acetylenedicarboxylates: Divergent Synthesis of Multi‐functionalized Pyrazolones and C‐Tethered Bispyrazol‐5‐ols.
Authors: Tu Xing‐Chao , Feng Hui , Tu Man‐Su , Jiang Bo , Wang Shu‐Liang , Tu Shu‐Jiang
Published: September 2012

The reaction of equimolar amounts of aldehydes bearing electron‐donating aryl groups, hydrazines and esters (II) results in formation of pyrazolones.
ChemInform Abstract: Palladium‐Catalyzed Aerobic Oxidative C—H Amination: Synthesis of 2‐Unsubstituted and 2‐Substituted N‐Aryl Benzimidazoles.
Authors: Kumar Rapolu Kiran , Punniyamurthy Tharmalingam
Published: September 2012

A general synthesis of 2‐unsubstituted and 2‐substituted N‐arylbenzimidazoles nvolves the Pd‐catalyzed oxidative cyclization of bis(aryl)amidines.
ChemInform Abstract: Phenyliodine Bis(trifluoroacetate) Mediated Intramolecular Oxidative Coupling of Electron‐Rich N‐Phenyl Benzamides.
Authors: Yu Zhengsen , Ma Lijuan , Yu Wei
Published: September 2012

Optimized metal‐free conditions are elaborated for the title reaction and a variety of the desired heterocycles can be prepared under conditions A).
ChemInform Abstract: DDQ‐Promoted C—S Bond Formation: Synthesis of 2‐Aminobenzothiazole Derivatives under Transition‐Metal‐, Ligand‐, and Base‐Free Conditions.
Authors: Wang Rui , Yang Wen‐juan , Yue Liang , Pan Wei , Zeng Hong‐yao
Published: September 2012

Various target compounds are available starting from o‐iodobenzothioureas.
ChemInform Abstract: Design, Synthesis and Cytotoxicity of Novel 2‐Arylvinyl‐4‐aminoquinoline Derivatives.
Authors: Jiang Nan , Zhai Xin , Chen Zhichao , Liang Chuang , Sun Chao , Han Jing , Gong Ping
Published: September 2012

Aminoquinoline derivatives (Va)‐(Vc) show 5.7‐ to 112‐fold better cytotoxic activities against four human cancer cell lines than the positive control iressa.
ChemInform Abstract: An Unexpected Silver Triflate Catalyzed Reaction of 2‐Alkynylbenzaldehyde with 2‐Isocyanoacetate.
Authors: Zheng Danqing , Li Shaoyu , Wu Jie
Published: September 2012

The title reaction does not produce a cyclic system including an oxazole ring, but a n isoquinoline system.
ChemInform Abstract: KOtBu‐Mediated Synthesis of Phenanthridinones and Dibenzoazepinones.
Authors: Bhakuni Bhagat Singh , Kumar Amit , Balkrishna Shah Jaimin , Sheikh Javeed Ahmed , Konar Sanjit , Kumar Sangit
Published: September 2012

The heterocyclic systems are available in the presence of either KOtBu or AIBN.
ChemInform Abstract: A One‐Pot Double C—H Activation Palladium Catalyzed Route to a Unique Class of Highly Functionalized Thienoisoquinolines.
Authors: Wong Nicholas W. Y. , Forgione Pat
Published: September 2012

A regioselective C—H activation approach is used to prepare biologically relevant title compounds.
ChemInform Abstract: Silver Triflate and Palladium Acetate Co‐Catalyzed Reaction of N′‐(2‐Alkynylbenzylidene)hydrazide with N‐Allyl Ynamide.
Authors: Huang Ping , Chen Zhiyuan , Yang Qin , Peng Yiyuan
Published: September 2012

The reaction affords various 2‐amino‐H‐pyrazolo[5,1‐a]isoquinolines.
ChemInform Abstract: Design, Synthesis, and in vitro Antiproliferative Activity of Novel Dasatinib Derivatives.
Authors: Cai Jin , Zhang Shaoning , Zheng Ming , Wu Xiaoqing , Chen Junqing , Ji Min
Published: September 2012

Novel dasatinib analogues (I) are designed, synthesized and screened for their in vitro cytostatic effect on two human myeloid leukemia cell lines.
ChemInform Abstract: Synthesis of 5‐Benzyl‐2‐phenylpyrazolo[1,5‐a]pyrazin‐4,6(5H,7H)‐dione Derivatives and Discovery of an Apoptosis Inducer for H322 Lung Cancer Cells.
Authors: Lv Hong‐Shui , Kong Xiang‐Qian , Ming Qian‐Qian , Jin Xing , Miao Jun‐Ying , Zhao Bao‐Xiang
Published: September 2012

Novel pyrazolo‐fused dihydropyrazine diones (I) are synthesized and tested for their inhibitory effects on the proliferation of A549 and H322 lung cancer cells.
ChemInform Abstract: Metal‐Free Catalytic Enantioselective C—B Bond Formation: (Pinacolato)boron Conjugate Additions to α,β‐Unsaturated Ketones, Esters, Weinreb Amides, and Aldehydes Promoted by Chiral N‐Heterocyclic Carbenes.
Authors: Wu Hao , Radomkit Suttipol , O'Brien Jeannette M. , Hoveyda Amir H.
Published: September 2012

Chiral imidazolium salts are transformed in situ to the catalytically active diastereo‐ and enantiomerically pure N‐heterocyclic carbenes by DBU.
ChemInform Abstract: Base‐Free Dehydrogenative Coupling of Enolizable Carbonyl Compounds with Silanes.
Authors: Koenigs C. David F. , Klare Hendrick F. T. , Ohki Yasuhiro , Tatsumi Kazuyuki , Oestreich Martin
Published: September 2012

The catalysis with complex (I) proceeds mostly chemoselectively for a wide range of linear or cyclic, aromatic or aliphatic ketones.
ChemInform Abstract: Sesquiterpenes and Cyclopeptides from the Endophytic Fungus Trichoderma asperellum Samuels, Lieckf. & Nirenberg.
Authors: Ding Gang , Chen Amanda Juan , Lan Jin , Zhang Hongwu , Chen Xiangdong , Liu Xingzhong , Zou Zhongmei
Published: September 2012

Trichodone A (I), B (II) and C (III) are isolated together with the known cyclopeptides PF1022F and halobacillin.
ChemInform Abstract: A Simple Protocol for the Synthesis of Triazole‐Linked Cyclic Glycopeptidomimetics: A Sequential Ugi‐MCR and Azide—Alkyne Cycloaddition Approach.
Authors: Samarasimhareddy M. , Hemantha Hosahalli P. , Sureshbabu Vommina V.
Published: September 2012

An Ugi four‐component coupling reaction is developed to prepare functionalized azido alkynes of type (V).
ChemInform Abstract: Enantioselective Straightforward Access to Benzo[b]thiophene Analogues of Azatoxin.
Authors: Gracia Stephanie , Marion Cedric , Rey Jullien , Popowycz Florence , Pellet‐Rostaing Stephane , Lemaire Marc
Published: September 2012

The benzothiophene analogue (Xb) of azatoxin (XI) and related compounds are synthesized by a Pictet—Spengler condensation of aldehydes with key intermediate (VIII).
ChemInform Abstract: Degradation Issues in Solid Oxide Cells During High Temperature Electrolysis
Authors: Sohal M. S. , O'Brien J. E. , Stoots C. M. , Sharma V. I. , Yildiz B. , Virkar A.
Published: September 2012

Review: 22 refs.
ChemInform Abstract: Practical Approach to Zeolitic Membranes and Coatings: State of the Art, Opportunities, Barriers, and Future Perspectives
Authors: Gascon Jorge , Kapteijn Freek , Zornoza Beatriz , Sebastian Victor , Casado Clara , Coronas Joaquin
Published: September 2012

Review: 212 refs.
ChemInform Abstract: Optimized Fabrication of High Quality La0.67Sr0.33MnO3 Thin Films Considering All Essential Characteristics
Authors: Boschker H. , Huijben M. , Vailionis A. , Verbeeck J. , van Aert S. , Luysberg M. , Bals S. , van Tendeloo G. , Houwman E. P. , Koster G. , et al. et al.
Published: September 2012

Review: 61 refs.
ChemInform Abstract: Transition Metal Complexes Meet the Rylenes
Authors: Castellano Felix N.
Published: September 2012

Review: 59 refs.
ChemInform Abstract: Advances in the Mechanistic Understanding of Selected Reactions of Transition Metal Polyaminecarboxylate Complexes
Authors: Brausam Ariane , Van Eldik Rudi
Published: September 2012

Review: 76 refs.
ChemInform Abstract: Metal‐Catalyzed Furan Synthesis. A Review
Authors: Moran Wesley J. , Rodriguez Arantxa
Published: September 2012

Review: 95 refs.
ChemInform Abstract: Non‐asymmeric Organocatalysis
Authors: Renzi Polyssena , Bella Marco
Published: September 2012

Review: 86 refs.
ChemInform Abstract: Photochemical Key Steps in Organic Synthesis
Authors: Hoffmann Norbert
Published: September 2012

Review: 318 refs.
ChemInform Abstract: Photolabile Protecting Groups in Organic Synthesis
Authors: Bochet Christian G. , Blanc Aurelien
Published: September 2012

Review: 135 refs.
ChemInform Abstract: Bioavailability Enhancement and Brain Targeting of Curcumin: A Potential Antitumor Agent
Authors: Kaur Indu Pai , Kakkar Vandita
Published: September 2012

Review: 168 refs.
ChemInform Abstract: Novel Glycomimetics: Anomeric and N‐Glycosyl Sulfonamides
Authors: Colinas Pedro A.
Published: September 2012

Review: 50 refs.
ChemInform Abstract: 2‐Mercaptobenzothiazole and Its Derivatives. Syntheses, Reactions, and Applications
Authors: Wu Feng‐Ling , Hussein Waleed M. , Ross Benjamin P. , McGeary Ross P.
Published: September 2012

Review: 257 refs.
ChemInform Abstract: Acyclic Aminocarbenes in Catalysis
Authors: Slaughter LeGrande M.
Published: September 2012

Review: 170 refs.
ChemInform Abstract: Production of Microbial Biosurfactants by Solid‐State Cultivation
Authors: Krieger Nadia , Camilios Neto Doumit , Mitchell David Alexander
Published: September 2012

Review: 28 refs.
ChemInform Abstract: Carbon Nanotubes in Sample Preparation
Authors: Samanidou Victoria F. , Karageorgou Eftichia G.
Published: September 2012

Review: 129 refs.
ChemInform Abstract: Plant Cell Walls to Ethanol
Authors: Jordan Douglas B. , Bowman Michael J. , Braker Jay D. , Dien Bruce S. , Hector Ronald E. , Lee Charles C. , Mertens Jeffrey A. , Wagschal Kurt
Published: September 2012

Review: 194 refs.
ChemInform Abstract: Spinach A Software Library for Simulation of Spin Dynamics in Large Spin Systems
Authors: Hogben H. J. , Krzystyniak M. , Charnock G. T. P. , Hore P. J. , Kuprov Ilya
Published: September 2012

Review: 100 refs.
ChemInform Abstract: CH/π‐Interactions
Authors: Tsuzuki Seiji
Published: September 2012

Review: 151 refs.
ChemInform Abstract: Two‐Photon Fluorescent Probes for Bioimaging.
Authors: Yao Sheng , Belfield Kevin D.
Published: September 2012

Review: ca. 90 refs.
Resource Efficiency Potentials of Innovations in Resource‐Intensive Production Processes
Authors: Albrecht Stefan , Bollhöfer Esther , Brandstetter Peter , Fröhling Magnus , Mattes Katharina , Ostertag Katrin , Peuckert Jan , Seitz Ralph , Trippe Frederik , Woidasky Jörg
Published: September 2012

Ressourceneffizienz ist ein zentrales Element der Sicherung der industriellen Produktion in Deutschland und Europa und gleichzeitig eine wichtige Strategie zur Steigerung der Nachhaltigkeit. Umfangreiche Forschungsanstrengungen werden derzeit unternommen, um ressourceneffiziente Produktionsverfahren zu entwickeln und in der industriellen Praxis zu etablieren. Der Beitrag nimmt basierend auf einem Förderschwerpunkt des deutschen Bundesministeriums für Bildung und Forschung eine erste qualitative Einordnung der Ressourceneffizienzpotenziale vor, die mit ausgewählten aktuellen technologischen Entwicklungen im Bereich rohstoffintensiver Produktionsprozesse verbunden sind. An einem Branchenbeispiel werden die erwarteten Einsparpotenziale hinsichtlich kumuliertem Materialaufwand, Primärenergiebedarf und Treibhauspotenzial quantifiziert. Ergänzend werden ausgewählte Herausforderungen der Umsetzung dieser ressourceneffizienten Verfahrensinnovationen beleuchtet.
A comparison of nonlinear control performance assessment techniques for nonlinear processes
Authors: Yu Wei , Wilson David I. , Young Brent R.
Published: September 2012

Assessing the quality of industrial control loops is an important auditing task for the control engineer. However, there are complications when considering the ubiquitous nonlinearities present in many industrial control loops. If one simply ignores these nonlinearities, there is the danger of over‐estimating the performance of the control loop in rejecting disturbances and thereby possibly overlooking loops that need attention. To address this problem, several techniques have been recently developed to extend the control performance assessment (CPA) of single input/single output linear systems to nonlinear systems. This article surveys these nonlinear CPA techniques and compares their performances using three case studies. These results can be used to guide control engineers to select the most suitable CPA techniques for their particular applications. © 2012 Canadian Society for Chemical Engineering
Evaluating the Prognostic Value of Positron‐Emission Tomography Myocardial Perfusion Imaging Using Automated Software to Calculate Perfusion Defect Size
Authors: Williams Brent A. , Dorn Joan M. , LaMonte Michael J. , Donahue Richard P. , Trevisan Maurizio , Leonard Deborah A. , Greene Robert S. , Merhige Michael E.
Published: September 2012

Background:

Myocardial perfusion imaging by positron‐emission tomography (PET MPI) is regarded as a valid technique for the diagnosis of coronary artery disease (CAD), but the incremental prognostic value of PET MPI among individuals with known or suspected CAD is not firmly established.

Hypothesis:

Myocardial perfusion defect sizes as measured by PET MPI using automated software will provide incremental prognostic value for cardiac and all‐cause mortality.

Methods:

This study included 3739 individuals who underwent rest‐stress rubidium‐82 PET MPI for the evaluation of known or suspected CAD. Rest, stress, and stress‐induced myocardial perfusion defect sizes were determined objectively by automated computer software. Study participants were followed for a mean of 5.2 years for cardiac and all‐cause mortality. Cox proportional hazards models were developed to evaluate the incremental prognostic value of PET MPI.

Results:

A strong correlation was observed between perfusion defect sizes assessed visually and by automated software (r = 0.76). After adjusting for cardiac risk factors, known CAD, noncoronary vascular disease, and use of cardioprotective medications, stress perfusion defect size was strongly associated with cardiac death (P < 0.001). Rest perfusion defects demonstrated a stronger association with cardiac death (P < 0.001) than stress‐induced perfusion defects (P = 0.01), yet both were highly significant. Similar patterns held for all‐cause death.

Conclusions:

The current study is the largest to date demonstrating PET MPI provides incremental prognostic value among individuals with known or suspected CAD. Automated calculation of perfusion defect sizes may provide valuable supplementary information to visual assessment.

This work was partially funded by a predoctoral fellowship grant awarded to the first author by the American Heart Association's Founders' Affiliate. Additional funding was provided by Niagara Falls Memorial Medical Center, Positron Corporation, the University at Buffalo, and Niagara University. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Growth of Plankton (Scenedesmus acutus (Chlorophyceae) and Moina macracopa (Cladocera)) on Domestic Wastewater
Authors: Nandini S. , Alonso‐Soto Ricardo , Sarma S. S. S.
Published: September 2012

The population growth of the freshwater chlorophyte, Scenedesmus acutus and the cladoceran Moina macrocopa cultured in the laboratory and in microcosms of a wastewater treatment plant was studied. S. acutus was cultured in a defined algal medium and mixed with wastewater. On diets of S. acutus cultured using Bold medium or a mixture with wastewater, the peak densities of M. macrocopa were 6–7 ind. mL−1, while on a diet of algae cultured on wastewater alone the cladoceran density fluctuated around 2 ind. mL−1. Population growth rates of M. macrocopa, which ranged from 0.3 to 0.4 d−1, were significantly lower on alga cultured in wastewater alone. The body size structure of M. macrocopa was larger on algae cultured in Bold medium than in wastewater. Peak densities of M. macrocopa were around 700 ind. L−1 when the organic matter in the containers was supplemented with algae but it reached lower densities (400 ind. L−1) when cultured on the organic matter in wastewater alone. Our study indicates that the nutrients in the final stages of wastewater treatment can support the growth of both phytoplankton and zooplankton.
Measurement of Aluminum–Carbon Distances Using S‐RESPDOR NMR Experiments
Authors: Pourpoint Frédérique , Trébosc Julien , Gauvin Régis M. , Wang Qiang , Lafon Olivier , Deng Feng , Amoureux Jean‐Paul
Published: September 2012

It is demonstrated that reliable aluminum–carbon distances can be measured in samples with 13C natural abundance by NMR spectroscopy. Overcoupled resonators, with only one radio‐frequency synthesizer and one amplifier, are used to irradiate in the same pulse sequence 27Al and 13C nuclei, which differ by only 3.6 % in Larmor frequencies. The combination of 27Al saturation pulse with heteronuclear dipolar recoupling yields dipolar dephasing of the 13C signal, which only depends on the AlC distance and the efficiency of the saturation pulse. Therefore, reliable distances can be obtained by rapid fitting of experimental data to an analytical expression. It is demonstrated that with natural isotopic abundance this approach allows recovery of AlC distances of 216 pm for the covalent bond in lithium tetraalkyl aluminates, commonly used as a co‐catalyst in olefin polymerization processes, and which range from 274 to 381 pm for the three carbon atoms in aluminum lactate. The accuracy of the measured internuclear distances is carefully estimated.
A Facile Approach to Highly Efficient and Thermally Stable Solid‐State Emitters: Knitting up AIE‐Active TPE Luminogens by Aryl Linkers
Authors: Chan Carrie Yin Kwan , Lam Jacky Wing Yip , Zhao Zujin , Deng Chunmei , Chen Shuming , Lu Ping , Sung Herman H. Y. , Kwok Hoi Sing , Ma Yuguang , Williams Ian D. , Tang Ben Zhong
Published: September 2012

A facile approach to thermally stable and efficient solid‐state emitters is proposed. By hooking up tetraphenylethene (TPE) units through aryl linkers under Suzuki coupling conditions, a series of arylene bis(tetraphenylethene)s (TPE‐Ar‐TPE Ar=2,5‐dimethyl‐1,4‐phenylene, 2,5‐bis(hexyloxyl)‐1,4‐phenylene, 1,5‐naphthylene, and 9,10‐anthracenylene) are prepared in satisfactory to high yields (67–96 %). These molecules are nonluminescent when dissolved in solutions but become highly emissive when aggregated in poor solvents or fabricated as thin film in the solid state, displaying a phenomenon of aggregation‐induced emission. Fluorescence quantum yields of 100 % were achieved in the amorphous films of the luminogens. The luminogens exhibit mechano‐, vapo‐, and thermochromism: their emissions can be repeatedly switched between blue and blue‐green colors by simple grinding‐fuming and grinding‐heating cycles owing to the morphological change from a crystalline to an amorphous state and vice versa. These compounds are thermally stable, losing little of their weight at high temperatures of 421–452 °C. All the luminogens are morphological stable with high glass transition temperatures. Multilayer light‐emitting diodes with a device configuration of ITO/NPB/dye/TPBi/Alq3/LiF/Al are fabricated, which emit sky‐blue electroluminescence with maximum luminance and external quantum efficiency of 7900 cd m−2 and 2.1 %, respectively.
Unlike αβ T cells, γδ T cells, LTi cells and NKT cells do not require IRF4 for the production of IL‐17A and IL‐22
Authors: Raifer Hartmann , Mahiny Azita J. , Bollig Nadine , Petermann Franziska , Hellhund Anne , Kellner Kerstin , Guralnik Anna , Reinhard Katharina , Bothur Evita , Huber Magdalena , Bauer Stefan , Löhning Max , Kiss Elina A. , Ganal Stephanie C. , Diefenbach Andreas , Korn Thomas , Lohoff Michael
Published: September 2012

Apart from conventional CD4+ Th17 cells, the cytokines IL‐17A and IL‐22 can also be produced by γδ T cells, NK cells and lymphoid tissue inducer (LTi) cells. Th17 cells develop from precursor cells after T‐cell receptor stimulation in the presence of TGF‐β, IL‐6 and IL‐23. In contrast, a subset of γδ T cells (“γδT17”) is committed for fast IL‐17 production already in the thymus; however, γδ T cells can also produce IL‐17 after prolonged in vitro stimulation via their γδ T‐cell receptor plus IL‐23. Here, we show that γδ T‐, LTi‐ and NKT cells differ extensively from Th17 cells in their signalling requirements for the generation of IL‐17A and IL‐22. While production of these cytokines by Th17 cells totally depends on the transcription factor interferon regulatory factor 4 (IRF4), IRF4 is irrelevant in the other cell types. As for γδ T cells, this finding pertains to both thymic commitment and prolonged in vitro culture. Furthermore, IL‐17A‐producing γδ T cells accumulate in the central nervous system of IRF4 deficient (Irf4−/−) mice during experimental autoimmune encephalomyelitis. IL‐17A‐producing WT and Irf4−/− γδ T cells equally express CCR6 and lack CD27. The underlying IRF4‐independent pathway partially involves STAT3 during in vitro stimulation.
Unexpected One‐Step Formation of Iodo[1,3]dioxolo[4,5‐c]pyridine Derivatives by a Hofmann–Löffler–Freytag Reaction: Studies on the Synthesis of a Pyridine‐Containing Macrocycle
Authors: Lechel Tilman , Podolan Gabriel , Brusilowskij Boris , Schalley Christoph A. , Reissig Hans‐Ulrich
Published: September 2012

During attempts to prepare functionalized 5‐iodopyridine derivatives the unexpected formation of iodo[1,3]dioxolo[4,5‐c]pyridines was discovered. The conversion of 3‐alkoxypyridin‐4‐ols into the corresponding 5‐iodo compounds was achieved by reaction with one equivalent of iodine or tetramethylammonium dichloroiodate under basic conditions. When three equivalents of iodine were used in chlorinated solvents, after 5‐iodination, subsequent reaction of the 3‐alkoxy group took place to form a 1,3‐dioxolane ring with the 4‐hydroxyl group. Generation of the resulting iodo[1,3]dioxolo[4,5‐c]pyridines is explained by a radical process known as the Hofmann–Löffler–Freytag reaction. Two 6‐ethynylpyridine derivatives were examined in the iodination process to establish a route to pyridine‐containing macrocycles. The pentasubstituted 5‐iodopyridine derivative21could be prepared; however, attempts to achieve cyclotrimerization of this building block under different conditions were not successful. Reaction of21with copper chloride allowed isolation of a copper acetylide22, which aggregates to a triangular trimeric complex containing four copper(I) ions such as [23·Cu]+as monitored by ESI mass spectrometry.
Synthesis of [2‐(Trimethylsilyl)ethynyl]pyrazoles Based on Bis(trimethylsilyl)acetylene and Arylacetyl Chlorides
Authors: Pankova Alena S. , Golubev Pavel R. , Ananyev Ivan V. , Kuznetsov Mikhail A.
Published: September 2012

A practical approach to the synthesis of [2‐(trimethylsilyl)ethynyl]pyrazoles was developed through condensation of hydrazines with enynones that are easily accessible frombis(trimethylsilyl)acetylene and arylacetyl chlorides. Optimized conditions for reactions with monoarylhydrazines permit the chemoselective formation of 5‐alkynylpyrazoles in high yields (48–94 %). When monoalkylhydrazines or the parent hydrazine is used, mixtures of 3‐ and 5‐alkynylpyrazoles are formed in 73–79 % yields. The method uses inexpensive starting materials and can be applied to a variety of substrates, which makes it convenient for the synthesis of alkynylpyrazoles.
Synthesis of Unsaturated Macrocycles by Ru‐Catalyzed Ring‐Closing Metathesis: A Comparative Study
Authors: Grisi Fabia , Costabile Chiara , Grimaldi Anna , Viscardi Colomba , Saturnino Carmela , Longo Pasquale
Published: September 2012

The activity and stereoselectivity of phosphane‐ and N‐heterocyclic carbene (NHC)‐containing ruthenium benzylidene complexes have been evaluated in macrocyclic ring‐closing olefin metathesis to produce unsaturated lactones and lactams. The success of the macrocyclization depends on the nature of the ligand (phosphane or N‐heterocyclic carbene) on the ruthenium center and on the NHC properties. As for stereoselectivity, E/Z ratios seem to be influenced not only by the nature of the ruthenium catalyst but also by the thermodynamic stabilities of the resulting unsaturated macrocycles, as confirmed by theoretical results.