bluuebunny/crossref_metadata_2025_split huggingface dataset:
Whole‐Cell One‐Pot Biosynthesis of Azelaic Acid
Authors: Otte Konrad B. , Kittelberger Jens , Kirtz Marko , Nestl Bettina M. , Hauer Bernhard 
Published: December 2013

AbstractPolymers benefit from the use of biogenic resources such as fatty acids. They enable easy access to valuable monomeric building blocks, which, in comparison to their exclusively fossil counterparts, lead to products with improved physicochemical properties. Monomers of special interest are medium‐chain dicarboxylic acids, which are not easy to obtain by traditional chemical means. Previously, we established an in vitro pathway that combined a 9‐lipoxygenase and a 9/13‐hydroperoxide lyase, which enabled the conversion of linoleic acid via a hydroperoxy intermediate into 9‐oxononanoic acid, the precursor of azelaic acid. Herein, we aimed for the further development of the multi‐enzyme cascade, which included the oxidation of 9‐oxononanoic acid and the establishment of a suitable whole‐cell catalyst. A detailed investigation of the simultaneous in vitro reaction setup revealed that both lipoxygenase activation and the subsequent hydroperoxide lyase reaction depend on the hydroperoxide reaction intermediate. For the activation of lipoxygenase, the hydroperoxide lyase activity, therefore, has to be significantly reduced. In accordance with these observations, we established a suitable dual‐expression system and we further demonstrated that endogenous E. coli redox enzymes are feasible to oxidize 9‐oxononanoic acid to azelaic acid. The resulting whole‐cell catalyst is, therefore, able to perform the direct bioconversion of linoleic acid into azelaic acid. The use of organic solvent as the second phase improved the overall performance of the E. coli host strain. The developed one‐pot, single‐step process afforded 29 mg L−1 of azelaic acid within 8 h with a substrate conversion of 34 % and a selectivity of 47 %.
New Insight into Platinum Dissolution from Nanoparticulate Platinum‐Based Electrocatalysts Using Highly Sensitive In Situ Concentration Measurements
Authors: Jovanovič Primož , Pavlišič Andraž , Šelih Vid Simon , Šala Martin , Hodnik Nejc , Bele Marjan , Hočevar Samo , Gaberšček Miran 
Published: December 2013

AbstractTime‐ and potential‐resolved electrochemical Pt dissolution from commercial Pt and prepared PtCu alloy nanoparticulate catalysts have been studied under potentiodynamic conditions in 0.1 M HClO4 by using on‐line inductively coupled plasma mass spectrometry (ICP‐MS). For the first time the exact amount of dissolved Pt per cycle has been measured on real electrocatalysts. Results show clearly that Pt dissolution depends on the particle size: approximately seven times as much Pt is released into the solution from commercial 3 nm Pt particles as from a commercial 30 nm Pt sample. The stability of our prepared PtCu electrocatalyst is higher than that of a commercial 3 nm electrocatalyst, which is, however, still slightly lower than that of a commercial 30 nm Pt electrocatalyst.
Monitoring of a Pharmaceuticals Freeze‐Drying Process by Model‐Based Process Analytical Technology Tools
Authors: Bosca Serena , Fissore Davide 
Published: December 2013

AbstractPharmaceuticals freeze‐drying requires a careful monitoring to preserve product quality. This is a challenging task as it is not possible to measure inline the variables of interest, i.e., temperature and residual amount of ice in the product in the primary drying stage and residual unfrozen water in the secondary drying stage. Various sensors are available to estimate the state of the product, coupling experimental measures and a model of the process. Methods based on the measure of product temperature and on the pressure rise test are discussed and compared by means of experimental investigations. The former is a local intrusive method, as it requires placing thermocouples in various vials, but allows monitoring the batch taking into account its non‐uniformity, while the latter is a global and non‐intrusive method which permits a partial insight into process dynamics.
Oxidative Addition to Palladium(0) Diphosphine Complexes: Observations of Mechanistic Complexity with Iodobenzene as Reactant
Authors: Kurbangalieva Almira , Carmichael Duncan , Hii K. K. (Mimi) , Jutand Anny , Brown John M. 
Published: December 2013

AbstractUsing a combination of electrochemical and NMR techniques, the oxidative addition of PhX to three closely related bis‐diphosphine P2Pd0 complexes, where the steric bulk of just one substituent was varied, has been analysed quantitatively. For the complex derived from MetBu2P, a rapid reaction ensued with PhI following an associative mechanism, and data was also obtained by cyclic voltammetry for PhOTs, PhBr and PhCl, revealing distinct relative reactivities from the related (PCx3)2Pd complex (Cx=cyclohexyl) previously studied. The corresponding EttBu2P complex reacted more slowly with PhI and was studied by NMR spectroscopy. The reaction course indicated a mixture of pathways, with contribution from a component that was [PhI] independent. For the CxtBu2P complex, reaction was again monitored by NMR spectroscopy, and was even slower. At high PhI concentrations reaction was predominantly linear in [PhI], but at lower concentrations the [PhI] independent pathway was again observed, and an accelerating influence of the reaction product was observed over the concentration range. The NMR spectra of the EttBu2P and CxtBu2P complexes conducted in C6D6 shows some line broadening that was augmented on addition of PhI. NMR experiments carried out in parallel show that there is rapid ligand exchange between free phosphine and the Pd2Pd complex and also a slow ligand crossover between different P2Pd complexes. DFT calculations were carried out to further test the feasibility of C6D6 involvement in the oxidative addition process, and located Van der Waals complexes for association of the P2Pd0 complexes with either PhI or benzene. PhI or solvent‐assisted pathways for ligand loss are both lower in energy than direct ligand dissociation. Taken all together, these results provide a consistent explanation for the surprising complexity of an apparently simple reaction step. The clear dividing line between reactions that give a di‐ or monophosphine palladium complex after oxidative addition clarifies the participation of the ligand in coupling catalysis.
Hexanuclear Gold(I) Phosphide Complexes as Platforms for Multiple Redox‐Active Ferrocenyl Units
Authors: Lee Terence Kwok‐Ming , Cheng Eddie Chung‐Chin , Zhu Nianyong , Yam Vivian Wing‐Wah 
Published: December 2013

AbstractThe synthesis, X‐ray crystal structures, electrochemical, and spectroscopic studies of a series of hexanuclear gold(I) μ3‐ferrocenylmethylphosphido complexes stabilized by bridging phosphine ligands, [Au6(PP)n(Fc‐CH2‐P)2][PF6]2 (n=3, PP=dppm (bis(diphenylphosphino)methane) (1), dppe (1,2‐bis(diphenylphosphino)ethane) (2), dppp (1,3‐bis(diphenylphosphino)propane) (3), Ph2PN(C3H7)‐PPh2 (4), Ph2PN(Ph‐CH3‐p)PPh2 (5), dppf (1,1′‐bis(diphenylphosphino)ferrocene) (6); n=2, PP=dpepp (bis(2‐diphenylphosphinoethyl)phenylphosphine) (7)), as platforms for multiple redox‐active ferrocenyl units, are reported. The investigation of the structural changes of the clusters has been probed by introducing different bridging phosphine ligands. This class of gold(I) μ3‐ferrocenylmethylphosphido complexes has been found to exhibit one reversible oxidation couple, suggestive of the absence of electronic communication between the ferrocene units through the Au6P2 cluster core, providing an understanding of the electronic properties of the hexanuclear AuI cluster linkage. The present complexes also serve as an ideal system for the design of multi‐electron reservoir and molecular battery systems.
Isomerization‐ and Temperature‐Jump‐Induced Dynamics of a Photoswitchable β‐Hairpin
Authors: Deeg Andreas A. , Rampp Michael S. , Popp Alexander , Pilles Bert M. , Schrader Tobias E. , Moroder Luis , Hauser Karin , Zinth Wolfgang 
Published: December 2013

AbstractConformational changes in proteins and peptides can be initiated by diverse processes. This raises the question how the variation of initiation mechanisms is connected to differences in folding or unfolding processes. In this work structural dynamics of a photoswitchable β‐hairpin model peptide were initiated by two different mechanisms: temperature jump (T‐jump) and isomerization of a backbone element. In both experiments the structural changes were followed by time‐resolved IR spectroscopy in the nanosecond to microsecond range. When the photoisomerization of the azobenzene backbone switch initiated the folding reaction, pronounced absorption changes related to folding into the hairpin structure were found with a time constant of about 16 μs. In the T‐jump experiment kinetics with the same time constant were observed. For both initiation processes the reaction dynamics revealed the same strong dependence of the reaction time on temperature. The highly similar transients in the microsecond range show that the peptide dynamics induced by T‐jump and isomerization are both determined by the same mechanism and exclude a downhill‐folding process. Furthermore, the combination of the two techniques allows a detailed model for folding and unfolding to be presented: The isomerization‐induced folding process ends in a transition‐state reaction scheme, in which a high energetic barrier of 48 kJ mol−1 separates unfolded and folded structures.
Synthesis of Polycyclic Indole Skeletons by a Gold(I)‐Catalyzed Cascade Reaction
Authors: Wang Tao , Shi Shuai , Pflästerer Daniel , Rettenmeier Eva , Rudolph Matthias , Rominger Frank , Hashmi A. Stephen K. 
Published: December 2013

AbstractThe conversion of simple, easily available urea‐substituted 3‐phenylpropargyl alcohols catalyzed by a simple IPr–gold(I) catalyst in a gold(I)‐catalyzed cascade reaction composing of a gold‐catalyzed nucleophilic addition and a subsequent gold‐catalyzed substitution reaction delivers 1H‐imidazo[1, 5−a]indol‐3(2 H)‐ones. Other gold(I) catalysts or silver catalysts gave lower yields and often gave other side products. Gold(III) and copper(II) catalysts decomposed the starting material. Twelve examples, including donor and acceptor substituents on the distal nitrogen of the urea substructure, are provided. An X‐ray crystal structure analysis confirmed the structural assignment. The mechanistic investigation including isolation and further conversion of intermediates and reactions with enantiopure starting materials indicated that after the nucleophilic‐addition step, the substrate undergoes an SN1‐type benzylic substitution reaction at the indolyl alcohol intermediate or an intramolecular hydroamination reaction of the 2‐vinylindole intermediate.
Boryl‐Functionalized σ‐Alkynyl and Vinylidene Rhodium Complexes: Synthesis and Electronic Properties
Authors: Braunschweig Holger , Brown Christopher K. L. , Dewhurst Rian D. , Jimenez‐Halla J. Oscar C. , Kramer Thomas , Krummenacher Ivo , Pfaffinger Bernd 
Published: December 2013

AbstractThe synthesis, reactivity, and properties of boryl‐functionalized σ‐alkynyl and vinylidene rhodium complexes such as trans‐[RhCl(CCHBMes2)(PiPr3)2] and trans‐[Rh(CCBMes2)(IMe)(PiPr3)2] are reported. An equilibrium was found to exist between rhodium vinylidene complexes and the corresponding hydrido σ‐alkynyl complexes in solution. The complex trans‐[Rh(CCBMes2)(IMe)(PiPr3)2] (IMe=1,3‐dimethylimidazol‐2‐ylidene) was found to exhibit solvatochromism and can be quasireversibly oxidized and reduced electrochemically. Density functional calculations were performed to determine the reaction mechanism and to help rationalize the photophysical properties of trans‐[Rh(CCBMes2)(IMe)(PiPr3)2].
Electrophile‐Induced Nucleophilic Substitution of the nido‐Dicarbaundecaborate Anion nido‐7,8‐C2B9H12− by Conjugated Heterodienes
Authors: Frank René , Adhikari Anup Kumar , Auer Henry , Hey‐Hawkins Evamarie 
Published: December 2013

AbstractSubstitution of the dicarbaundecaborate anion nido‐7,8‐C2B9H12− (1) by precise hydride abstraction followed by nucleophilic attack usually leads to symmetric products 10‐R‐nido‐7,8‐C2B9H11. However, thioacetamide (MeC(S)NH2) as nucleophile and acetone/AlCl3 as hydride abstractor gave asymmetric 9‐[MeC(NHiPr)S]‐nido‐7,8‐C2B9H11 (2), whereas N,N‐dimethylthioacetamide (MeC(S)NMe2) gave the expected symmetric 10‐[MeC(NMe2)S]‐nido‐7,8‐C2B9H11 (4). For the formation of 2, acetone and thioacetamide are assumed to give the intermediate MeC(S)N(CMe2) (3), which then attacks 1 with formation of 2. Similarly, reaction of acetyliminium chloride [MeC(O)NH(CPh2)]Cl (5) with 1 in THF gave a mixture of 9‐ and 10‐substituted [MeC(NHCHPh2)O]‐nido‐7,8‐C2B9H11 (6 and 7, respectively). These reactions are the first examples in which compounds (here heterodienes) that unite the functionalities of both hydride acceptor and nucleophilic site react with 1 in a bimolecular fashion. Furthermore, the analogous reaction of 1 and 5 (in an equilibrium mixture with acetyl chloride and benzophenone imine) in MeCN afforded 10‐[MeC(NCPh2)NH]‐nido‐7,8‐C2B9H11 (8) and MeC(O)NHCHPh2 (9).
Tripod Immobilization of Triphenylphosphane on a Silica‐Gel Surface to Enable Selective Mono‐Ligation to Palladium: Application to Suzuki–Miyaura Cross‐Coupling Reactions with Chloroarenes
Authors: Iwai Tomohiro , Tanaka Ryotaro , Harada Tomoya , Sawamura Masaya 
Published: December 2013

AbstractA silica‐supported triphenylphosphane (Silica‐3p‐TPP) with a Ph3P‐type core, immobilized on a silica surface, was synthesized and characterized by nitrogen‐absorption measurements and solid‐state NMR spectroscopy. The tripodal immobilization constrains the mobility of the phosphane molecule and causes the lone pair on the phosphorus atom to face in the direction perpendicular to the support, resulting in the selective formation of a 1:1 metal–phosphane species that is free from unfavorable steric repulsions caused by the silica surface. Heterogeneous Pd catalysts created in this manner enabled room‐temperature Suzuki–Miyaura cross‐coupling reactions with unactivated chloroarenes, despite the moderate electronic and steric nature of the Ph3P‐based ligands. These catalysts also showed potential in reactions with more challenging substrates under mild conditions. Tripodally immobilized and well‐dispersed phosphanes on the silica surface were crucial for high catalytic activity.
ChemInform Abstract: Measurement of the Md3+/Md2+ Reduction Potential Studied with Flow Electrolytic Chromatography.
Authors: Toyoshima Atsushi , et al. et al. 
Published: December 2013

AbstractThe electrochemical reduction behavior of mendelevium is studied using a flow electrolytic chromatography apparatus employing C fibers modified with Nafion perfluorinated ion exchange resin as the working electrode.
ChemInform Abstract: Simultaneous Presence of (Si3O10)8‐ and (Si2O7)6‐ Groups in New Synthetic Mixed Sorosilicates: BaY4(Si2O7)(Si3O10) and Isotypic Compounds, Studied by Single‐Crystal X‐Ray Diffraction, Raman Spectroscopy and DFT Calculations.
Authors: Wierzbicka‐Wieczorek Maria , Toebbens Daniel M. , Kolitsch Uwe , Tillmanns Ekkehart 
Published: December 2013

AbstractThe new isotypic compounds BaY4(Si2O7)(Si3O10), SrYb4(Si2O7)(Si3O10), and SrSc4(Si2O7)(Si3O10) are synthesized by a high‐temperature flux growth method from mixtures of M2O3 (M: Y, Yb, Sc), BaCO3 or Sr(OH)2, an alkali metal carbonate, and MoO3 as a flux (Pt crucibles, 1150 °C, 3 h).
ChemInform Abstract: Synthesis and Properties of Charge‐Ordered Thallium Halide Perovskites, CsTI+0.5TI3+0.5X3 (X: F or Cl): Theoretical Precursors for Superconductivity?
Authors: Greenblatt M. , et al. et al. 
Published: December 2013

AbstractCsTlCl3 (I) is prepared via the precursor Cs2TlCl5·H2O (II) which is obtained by precipitation from a HCl solution of CsCl and Tl2O3 using H2O.
ChemInform Abstract: Two New Quaternary Selenostannates Synthesized under Solvothermal Conditions: Crystal Structure and Reflectance Spectra of (1,4‐dabH)2MnSnSe4 and (1,4‐dabH2) Cu2SnSe4.
Authors: Baiyin Menghe , Naren Jiruga , Gang Gang , Wang Xiaojing , Xu Xiaoqing 
Published: December 2013

Abstract(1,4‐dabH)2MnSnSe4 (I) (1,4‐dab: 1,4‐diaminobutane) and (1,4‐dabH2)Cu2SnSe4 (II) are prepared by solvothermal reaction of the elements in diaminobutane (autoclave, 160 °C, 7 d).
ChemInform Abstract: CrVI→CrV Transition in Uranyl Chromium Compounds: Synthesis and High‐Temperature X‐Ray Diffraction Study of Cs2[(UO2)2(CrO4)3].
Authors: Siidra Oleg I. , Nazarchuk Evgeny V. , Kayukov Roman A. , Bubnova Rimma S. , Krivovichev Sergey V. 
Published: December 2013

AbstractSingle crystals of Cs2[(UO2)2(CrO4)3] are hydrothermally synthesized from aqueous mixtures of (UO2)(NO3)2, CsNO3, and CrO3 (autoclave, 100 °C, 7 d, 92% yield).
ChemInform Abstract: Highly Efficient Synthesis of Heterocyclic and Alicyclic β2‐Amino Acid Derivatives by Catalytic Asymmetric Hydrogenation.
Authors: Li Lanning , Chen Bin , Ke Yuanyuan , Li Qing , Zhuang Yue , Duan Kun , Huang Yichun , Pang Jiyan , Qiu Liqin 
Published: December 2013

AbstractThe novel β2‐amino acid derivatives bearing heterocyclic or alicyclic groups are prepared with excellent enantioselectivities and high yields by catalytic asymmetric hydrogenation under mild conditions.
ChemInform Abstract: Cu‐Catalyzed Formal Methylative and Hydrogenative Carboxylation of Alkynes with Carbon Dioxide: Efficient Synthesis of α,β‐Unsaturated Carboxylic Acids.
Authors: Takimoto Masanori , Hou Zhaomin 
Published: December 2013

AbstractThe formal carboxylation of alkynes by a carboalumination (or hydroalumination)/carboxylation cascade is described.
ChemInform Abstract: Stereoselective Synthesis of β‐Alkylated α‐Amino Acids via Palladium‐Catalyzed Alkylation of Unactivated Methylene C(sp3)—H Bonds with Primary Alkyl Halides.
Authors: Zhang Shu‐Yu , Li Qiong , He Gang , Nack William A. , Chen Gong 
Published: December 2013

AbstractThis is a versatile method for the Pd‐catalyzed β‐alkylation of amides.
ChemInform Abstract: A Bifunctional Palladium/Acid Solid Catalyst Performs the Direct Synthesis of Cyclohexylanilines and Dicyclohexylamines from Nitrobenzenes.
Authors: Rubio‐Marques Paula , Leyva‐Perez Antonio , Corma Avelino 
Published: December 2013

AbstractOne‐pot formation of cyclohexylanilines and dicyclohexylamines is described with the degree of hydrogenation determined by the reaction temperature.
ChemInform Abstract: Gram‐Scale Ketone Synthesis by Direct Reductive Coupling of Alkyl Iodides with Acid Chlorides.
Authors: Lu Wenbin , Liang Zhuye , Zhang Yuwei , Wu Fan , Qian Qun , Gong Hegui 
Published: December 2013

AbstractThis procedure is also compatible with the application of crude acid chlorides generated in situ by reaction of the corresponding acids with SOCl2.
ChemInform Abstract: Synthesis of Aryl Sulfonamides via Palladium‐Catalyzed Chlorosulfonylation of Arylboronic Acids.
Authors: DeBergh J. Robb , Niljianskul Nootaree , Buchwald Stephen L. 
Published: December 2013

AbstractA novel, mild palladium‐catalyzed chlorosulfonylation of boronic acids is developed.
ChemInform Abstract: Pd(0)‐Catalyzed Sequential C—N Bond Formation via Allylic and Aromatic C—H Amination of α‐Methylstyrenes with Diaziridinone.
Authors: Ramirez Thomas A. , Wang Qian , Zhu Yingguang , Zheng Huaiji , Peng Xingao , Cornwall Richard G. , Shi Yian 
Published: December 2013

AbstractThe title method allows the conversion of various substituted α‐methylstyrenes into spirocyclic indolines.
ChemInform Abstract: Synthesis of N‐Methylcarbazoles from N‐(2‐Iodoaryl)‐N‐methylanilines in the Presence of Potassium tert‐Butoxide and Iron(II) Bromide.
Authors: Melnika I. , Bringis K. , Katkevics M. 
Published: December 2013

AbstractThe preparation of N‐methylcarbazoles is achieved from N‐iodoaryl‐N‐methylanilines (V) and (XI) without the use of toxic transition metals or special techniques for generation of radicals.
ChemInform Abstract: Stereoselective Rhodium‐Catalyzed [(3 + 2) + 2] Carbocyclization Reaction of Trialkoxysilyl‐Substituted Alkenylidenecyclopropanes with Monosubstituted Alkynes.
Authors: Evans P. Andrew , Baikstis Tomass , Inglesby Phillip A. 
Published: December 2013

AbstractAll compounds are isolated in high diastereopurity of at least 96% d.e.
ChemInform Abstract: Synthesis of Monospiro‐2‐amino‐4H‐pyran Derivatives Catalyzed by Propane‐1‐sulfonic Acid‐Modified Magnetic Hydroxyapatite Nanoparticles.
Authors: Jalili‐Baleh Leili , Mohammadi Narges , Khoobi Mehdi , Ma'mani Leila , Foroumadi Alireza , Shafiee Abbas 
Published: December 2013

AbstractA variety of monospiro‐2‐aminopyran derivatives such as (IV), (VII), and (X) (24 examples) are synthesized via three‐component coupling of isatin (I) or ninhydrin (VIII) with malononitrile (II) and 1,3‐dicarbonyl compounds.
ChemInform Abstract: Au‐Catalyzed Formation of Functionalized Quinolines from 2‐Alkynyl Arylazide Derivatives.
Authors: Gronnier Colombe , Boissonnat Guillaume , Gagosz Fabien 
Published: December 2013

AbstractA novel gold‐catalyzed method to convert 2‐alkynyl arylazides into polysubstituted quinolines is developed.
ChemInform Abstract: Catalytic Asymmetric exo‐Selective [6 + 3] Cycloaddition of Iminoesters with Fulvenes.
Authors: Potowski Marco , Antonchick Andrey P. , Waldmann Herbert 
Published: December 2013

AbstractThe title reaction proceeds with high diastereo‐ and enantioselectivity and allows the selective formation of piperidine derivatives.
ChemInform Abstract: Synthesis and Biological Evaluation of Amino Analogues of Ludartin: Potent and Selective Cytotoxic Agents.
Authors: Lone Shabir H. , Bhat Khursheed A. , Shakeel‐u‐Rehman Shakeel‐u‐Rehman , Majeed Rabiya , Hamid Abid , Khuroo Mohd A. 
Published: December 2013

AbstractVarious amino‐analogues of the cytotoxic guaianolide ludartin are synthesized by Michael type addition of amines at the highly active α‐methylene‐γ‐lactone motif.
ChemInform Abstract: Cyclic Sulfoxides Garlicnins B2, B3, B4, C2, and C3 from Allium sativum.
Authors: Nohara Toshihiro , Fujiwara Yukio , Ikeda Tsuyoshi , Murakami Kohtaro , Ono Masateru , Nakano Daisuke , Kinjo Junei 
Published: December 2013

AbstractThe isolation of five novel natural sulfoxides as well as the elucidation of their relative structures are reported.
An Update on Lysine Deacylases Targeting the Expanding “Acylome”
Authors: Olsen Christian A. 
Published: December 2013

AbstractLysine ε‐amino acetylation has long been recognized as an epigenetically relevant post‐translational modification of multiple residues in histone proteins. However, it has become clear that lysine acetylation is not restricted to histones, and therefore, it may be involved in the regulation of a wide variety of proteins, some of which have been identified and studied in detail. More recently, post‐translational modifications of lysine side chains by additional acyl groups have also been identified, and some of these appear to be regulated by histone deacetylases (HDACs) and/or sirtuins. In this Concept, new developments are discussed with emphasis on the enzymes that have been shown to catalyze the cleavage of these novel marks, including new assays and inhibitors. Ultimately, a deeper understand of these mechanisms should facilitate the development of ligands with therapeutic potential.