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https://www.readbyqxmd.com/read/29761065/pulsed-magnetic-resonance-to-signal-enhance-metabolites-within-seconds-by-utilizing-para-hydrogen
#1
Sergey Korchak, Shengjun Yang, Salvatore Mamone, Stefan Glöggler
Diseases such as Alzheimer's and cancer have been linked to metabolic dysfunctions, and further understanding of metabolic pathways raises hope to develop cures for such diseases. To broaden the knowledge of metabolisms in vitro and in vivo, methods are desirable for direct probing of metabolic function. Here, we are introducing a pulsed nuclear magnetic resonance (NMR) approach to generate hyperpolarized metabolites within seconds, which act as metabolism probes. Hyperpolarization represents a magnetic resonance technique to enhance signals by over 10 000-fold...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29744285/allene-oxide-synthase-pathway-in-cereal-roots-detection-of-novel-oxylipin-graminoxins
#2
Alexander N Grechkin, Anna V Ogorodnikova, Alevtina M Egorova, Fakhima K Mukhitova, Tatiana M Ilyina, Bulat I Khairutdinov
Young roots of wheat, barley, and sorghum, as well as methyl jasmonate pretreated rice seedlings, undergo an unprecedented allene oxide synthase pathway targeted to previously unknown oxylipins 1 - 3 . These Favorskii-type products, (4 Z )-2-pentyl-4-tridecene-1,13-dioic acid ( 1 ), (2' Z )-2-(2'-octenyl)-decane-1,10-dioic acid ( 2 ), and (2' Z ,5' Z )-2-(2',5'-octadienyl)-decane-1,10-dioic acid ( 3 ), have a carboxy function at the side chain, as revealed by their MS and NMR spectral data. Compounds 1 - 3 were the major oxylipins detected, along with the related α-ketols...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29744284/structural-modulation-of-chromic-response-effects-of-binding-site-blocking-in-a-conjugated-calix-4-pyrrole-chromophore
#3
Václav Březina, Shinsuke Ishihara, Jan Lang, Lenka Hanyková, Katsuhiko Ariga, Jonathan P Hill, Jan Labuta
Herein, we modulate the chromic response of a highly colored tetrapyrrole macrocycle, namely, tetrakis(3,5-di- tert -butyl-4-oxocyclohexadien-2,5-yl)porphyrinogen ( OxP ) by structural modification. N-Benzylation at the macrocyclic nitrogen atoms leads to stepwise elimination of the two calix[4]pyrrole-type binding sites of OxP and serial variation of the chromic properties of the products, double N-benzylated Bz2 OxP and tetra N-benzylated Bz4 OxP . The halochromic (response to acidity) and solvatochromic (response to solvent polarity) properties were studied by using UV/Vis spectroscopy and NMR spectroscopy in nonpolar organic solvents...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29744283/persulfate-reaction-in-a-hair-bleaching-formula-unveiling-the-unconventional-reactivity-of-1-13-diamino-4-7-10-trioxatridecane
#4
Emanuele M Gargano, Giuseppe F Mangiatordi, Ingo Weber, Carsten Goebel, Domenico Alberga, Orazio Nicolotti, Wolfgang Ruess, Stefan Wierlacher
The stability and unconventional reactivity of 1,13-diamino-4,7,10-trioxatridecane in the presence of NH3 , H2 O2 , and (NH4 )2 S2 O8 are described. The ether-diamine is an ingredient marketed to hair salons and consumers for so-called "plex" services to compensate for hair damage during bleaching. The main reaction product identified is an unexpected azanyl ester derivative. This is considered relevant for the safety evaluation when used in cosmetic products. The mechanism of reaction was explored through DFT calculations...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29744282/trend-analysis-of-solid-state-structures-low-energy-conformational-reactions-involving-directed-and-coupled-movements-in-half-sandwich-compounds-cpfe-co-c-o-r-pph-3
#5
Henri Brunner, Takashi Tsuno
Trends in solid-state structures were used to identify preferred intramolecular movements in half-sandwich compounds [CpFe(CO){C(=O)R}PPh3 ]. Three weak interactions were analyzed: 1) the CH/π donor-acceptor interaction of phenyl rings in the PPh3 ligand, 2) the PhPPh3 face-on Cp stabilization, and 3) the hydrogen bond between the oxygen atom of the acyl group and an ortho -C-H bond of one of the PPh3 phenyl rings. Clockwise and counter-clockwise rotations established directed and coupled movements of the PPh3 ligand, the acyl group, and the phenyl rings within the PPh3 ligand...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29744281/trend-analysis-of-solid-state-structures-low-energy-conformational-reactions-involving-directed-and-coupled-movements-in-half-sandwich-compounds-cpfe-co-c-o-r-pph-3
#6
Henri Brunner, Takashi Tsuno
Invited for this month's cover picture are Prof. Dr. Henri Brunner from the University of Regensburg (Germany) and Prof. Dr. Takashi Tsuno from Nihon University (Japan). The cover picture shows the conformational reaction of JIDLUD→FIHTUL. The order of sample points of solid-state structures reveals information concerning low-energy, directed, and coupled movements in molecules. Read the full text of their Communication at https://doi.org/10.1002/open.201800007.
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29721402/scaffold-diversity-synthesis-delivers-complex-structurally-and-functionally-distinct-tetracyclic-benzopyrones
#7
Muthukumar G Sankar, Sayantani Roy, Tuyen Thi Ngoc Tran, Kathrin Wittstein, Jonathan O Bauer, Carsten Strohmann, Slava Ziegler, Kamal Kumar
Complexity-generating chemical transformations that afford novel molecular scaffolds enriched in sp 3 character are highly desired. Here, we present a highly stereoselective scaffold diversity synthesis approach that utilizes cascade double-annulation reactions of diverse pairs of zwitterionic and non-zwitterionic partners with 3-formylchromones to generate highly complex tetracyclic benzopyrones. Each pair of annulation partners adds to the common chroman-4-one scaffold to build two new rings, supporting up to four contiguous chiral centers that include an all-carbon quaternary center...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29686961/hierarchical-sapo-34-architectures-with-tailored-acid-sites-using-sustainable-sugar-templates
#8
Ivana Miletto, Chiara Ivaldi, Geo Paul, Stephanie Chapman, Leonardo Marchese, Robert Raja, Enrica Gianotti
In a distinct, bottom-up synthetic methodology, monosaccharides (fructose and glucose) and disaccharides (sucrose) have been used as mesoporogens to template hierarchical SAPO-34 catalysts. Detailed materials characterization, which includes solid-state magic angle spinning NMR and probe-based FTIR, reveals that, although the mesopore dimensions are modified by the identity of the sugar template, the desirable acid characteristics of the microporous framework are retained. When the activity of the hierarchical SAPO-34 catalysts was evaluated in the industrially relevant Beckmann rearrangement, under liquid-phase conditions, the enhanced mass-transport properties of sucrose-templated hierarchical SAPO-34 were found to deliver a superior yield of ϵ -caprolactam...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29657915/macromolecular-crowding-may-significantly-affect-the-performance-of-an-mri-contrast-agent-a-1-h-nmr-spectroscopy-microimaging-and-fast-field-cycling-nmr-relaxometry-study
#9
Ren-Hao Cheng, Jie-Min Chen, Yu-Wen Chen, Honghao Cai, Xiaohong Cui, Dennis W Hwang, Zhong Chen, Shangwu Ding
Contrast enhancement agents are often employed in magnetic resonance imaging (MRI) for clinical diagnosis and biomedical research. However, the current theory on MRI contrast generation does not consider the ubiquitous presence of macromolecular crowders in biological systems, which poses the risk of inaccurate data interpretation and misdiagnosis. To address this issue, herein the macromolecular crowding effects on MRI contrast agent are investigated with the 1 H relaxation rate of water in aqueous solutions of Dotarem with different concentrations of macromolecules...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29657914/manufacturing-nanoparticles-with-orthogonally-adjustable-dispersibility-in-hydrocarbons-fluorocarbons-and-water
#10
Lukas Zeininger, Lisa M S Stiegler, Luis Portilla, Marcus Halik, Andreas Hirsch
We describe a universal wet-chemical shell-by-shell coating procedure resulting in colloidal titanium dioxide (TiO2 ) and iron oxide (Fe3 O4 ) nanoparticles with dynamically and reversibly tunable surface energies. A strong covalent surface functionalization is accomplished by using long-chained alkyl-, triethylenglycol-, and perfluoroalkylphosphonic acids, yielding highly stabilized core-shell nanoparticles with hydrophobic, hydrophilic, or superhydrophobic/fluorophilic surface characteristics. This covalent functionalization sequence is extended towards a second noncovalent attachment of tailor-made nonionic amphiphilic molecules to the pristine coated core-shell nanoparticles via solvophobic (i...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29657913/triple-helicene-cage-three-dimensional-%C3%AF-conjugated-chiral-cage-with-six-5-helicene-units
#11
Tomoya Matsushima, Shoko Kikkawa, Isao Azumaya, Soichiro Watanabe
A three-dimensional π-conjugated chiral cage with six [5]helicene units (a triple helicene cage) was synthesized for the first time. Taking advantage of the Yamamoto coupling reaction, the triflate-substituted triple [5]helicene, a strained and preorganized precursor, was dimerized to afford the target compound. Single-crystal X-ray diffraction analysis revealed the unique structural features of the triple helicene cage: a cage-shaped rigid structure with outer helical grooves and an inner chiral cavity. All- P and all- M enantiomers were separated successfully by HPLC over a chiral column and their chiroptical properties were characterized by circular dichroism spectra...
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29657912/manufacturing-nanoparticles-with-orthogonally-adjustable-dispersibility-in-hydrocarbons-fluorocarbons-and-water
#12
Lukas Zeininger, Lisa M S Stiegler, Luis Portilla, Marcus Halik, Andreas Hirsch
Invited for this month's cover picture is the group of Prof. Dr. Andreas Hirsch from Friedrich Alexander University (Germany). The cover picture shows shell-by-shell coated nanoparticle 'chameleons'-wet-chemically surface-modified nanoparticles that can reversibly adjust their dispersibility to entirely orthogonal solvent environments. Read the full text of their Full Paper at https://doi.org/10.1002/open.201800011.
April 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29610717/direct-detection-of-the-ion-pair-to-free-ions-transformation-upon-complexation-with-an-ion-receptor-in-non-polar-solvents-by-using-conductometry
#13
Kazuya Iseda, Kenta Kokado, Kazuki Sada
In this study, we performed conductometry in various organic solvents to directly detect the transformation from tetrabutylammonium chloride ( TBACl ) ion-pair salt to the free ions through complexation with meso -octamethylcalix[4]pyrrole ( CP ), which is a well-known receptor for chloride anions. In the presence of CP , the conductivity of TBACl increases in various non-polar solvents, indicating that complexation with CP enhances the ionic dissociation of TBACl in such non-polar solvents. In other words, CP recognizes chloride as an ion-paired salt as well as a free anion in non-polar solvents...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531891/dye-displacement-assay-for-saccharides-using-benzoxaborole-hydrogels
#14
Emma V Lampard, Adam C Sedgwick, Thitima Sombuttan, George T Williams, Boontana Wannalerse, A Toby A Jenkins, Steven D Bull, Tony D James
Dye displacement assays are a simple but effective method to determine the concentration of target analytes. Previously, we have shown that phenylboronic acid pinacol ester hydrogels (borogels) can be used to develop a boronic acid-Alizarin red S dye displacement assay for the determination of fructose (orange to red). In this work, benzoxaborole hydrogels (BOBgels) were developed, and these BOBgels demonstrated an enhanced apparent binding affinity towards monosaccharides, in particular towards glucose.
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531890/boronate-based-fluorescence-probes-for-the-detection-of-hydrogen-peroxide
#15
Emma V Lampard, Adam C Sedgwick, Xiaolong Sun, Katherine L Filer, Samantha C Hewins, Gyoungmi Kim, Juyoung Yoon, Steven D Bull, Tony D James
In this work, we synthesized a series of boronate ester fluorescence probes ( E )-4,4,5,5-tetramethyl-2-(4-styrylphenyl)-1,3,2-dioxaborolane ( STBPin) , ( E )- N , N -dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)styryl)aniline ( DSTBPin) , ( E )-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)styryl)benzonitrile ( CSTBPin) , ( E )-2-(4-(4-methoxystyryl)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane ( MSTBPin) , ( E )- N , N -dimethyl-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)styryl)naphthalen-1-amine ( NDSTBPin ), and N , N -dimethyl-4-(2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)oxazol-5-yl)aniline ( DAPOX-BPin ) for the detection of hydrogen peroxide (H2 O2 )...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531889/early-stage-incorporation-strategy-for-regioselective-labeling-of-peptides-using-the-2-cyanobenzothiazole-1-2-aminothiol-bioorthogonal-click-reaction
#16
Kuo-Ting Chen, Christian Ieritano, Yann Seimbille
Herein, we describe a synthetic strategy for the regioselective labeling of peptides by using a bioorthogonal click reaction between 2-cyanobenzothiazole (CBT) and a 1,2-aminothiol moiety. This methodology allows for the facile and site-specific modification of peptides with various imaging agents, including fluorophores and radioisotope-containing prosthetic groups. We investigated the feasibility of an early-stage incorporation of dipeptide 1 into targeting vectors, such as c[RGDyK(C)] and HER2 pep , during solid-phase peptide synthesis...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531888/sulfenamides-as-building-blocks-for-efficient-disulfide-based-self-healing-materials-a-quantum-chemical-study
#17
Fernando Ruipérez, Maialen Galdeano, Ekiñe Gimenez, Jon M Matxain
The theoretical self-healing capacity of new sulfenamide-based disulfides is estimated by using theoretical methods of quantum chemistry. Starting from previously studied aromatic disulfides, the influence of inserting a NH group between the disulfide and the phenyl ring (forming the sulfenamide), as well as the role of the phenyl ring in the self-healing process is analyzed. Three parameters are used in the evaluation of the self-healing capacity: i) the probability to generate sulfenyl radicals, which is the first step of the process; ii) the effect of the hydrogen bonding, which affects the mobility of the chains; and iii) the height of the exchange reaction barrier...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531887/organometallic-nucleosides-synthesis-and-biological-evaluation-of-substituted-dicobalt-hexacarbonyl-2-deoxy-5-oxopropynyluridines
#18
Renata Kaczmarek, Dariusz Korczyński, Karolina Królewska-Golińska, Kraig A Wheeler, Ferman A Chavez, Agnieszka Mikus, Roman Dembinski
Reactions of dicobalt octacarbonyl [Co2 (CO)8 ] with 2'-deoxy-5-oxopropynyluridines and related compounds gave dicobalt hexacarbonyl nucleoside complexes (83-31 %). The synthetic outcomes were confirmed by X-ray structure determination of dicobalt hexacarbonyl 2'-deoxy-5-(4-hydroxybut-1-yn-1-yl)uridine, which exhibits intermolecular hydrogen bonding between a modified base and ribose. The electronic structure of this compound was characterized by the DFT calculations. The growth inhibition of HeLa and K562 cancer cell lines by organometallic nucleosides was examined and compared to that by alkynyl nucleoside precursors...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531886/dihydroxyacetone-an-updated-insight-into-an-important-bioproduct
#19
REVIEW
Rosaria Ciriminna, Alexandra Fidalgo, Laura M Ilharco, Mario Pagliaro
Currently obtained from glycerol through microbial fermentation, the demand of 1,3-dihydroxyacetone (DHA) has significantly grown during the course of the last decade, driven by the consumer passion for a tan and increasing awareness of UV photodamage to the skin caused by prolonged exposure to the sun. We provide an updated bioeconomy perspective into a valued bioproduct (DHA), whose supply and production from glycerol, we argue in this study, will rapidly expand and diversify, with important global health benefits...
March 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29531885/translational-chemistry-meets-gluten-related-disorders
#20
REVIEW
Karen M Lammers, Maria G Herrera, Veronica I Dodero
Gluten-related disorders are a complex group of diseases that involve the activation of the immune system triggered by the ingestion of gluten. Among these, celiac disease, with a prevalence of 1 %, is the most investigated, but recently, a new pathology, named nonceliac gluten sensitivity, was reported with a general prevalence of 7 %. Finally, there other less-prevalent gluten-related diseases such as wheat allergy, gluten ataxia, and dermatitis herpetiformis (with an overall prevalence of less than 0...
March 2018: ChemistryOpen
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