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Cornelius von Morze, Michael A Ohliger, Irene Marco-Rius, David M Wilson, Robert R Flavell, David Pearce, Daniel B Vigneron, John Kurhanewicz, Zhen J Wang
PURPOSE: The purpose of this study was to investigate the hyperpolarized ketone body 13 C-acetoacetate (AcAc) and its conversion to 13 C-β-hydroxybutyrate (βOHB) in vivo, catalyzed by β-hydroxybutyrate dehydrogenase (BDH), as a novel direct marker of mitochondrial redox state. METHODS: [1,3-13 C2 ]AcAc was synthesized by hydrolysis of the ethyl ester, and hyperpolarized via dissolution DNP. Cold storage under basic conditions resulted in sufficient chemical stability for use in hyperpolarized (HP) MRI studies...
January 3, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Wei Jie Teo, Shaozhong Ge
We report the first catalytic diborylation of 1,1-disubstituted vinylarenes with pinacolborane using a cobalt catalyst generated from bench-stable Co(acac)2 and xantphos. A wide range of 1,1-disubstituted vinylarenes underwent this transformation to produce the corresponding gem-bis(boryl)alkanes in modest to high isolated yields. This cobalt-catalyzed protocol can be readily conducted on a gram scale without the use of a dry box and represents a practical and effective approach to access a wide range of branched gem-bis(boryl)alkanes...
November 29, 2017: Angewandte Chemie
Sanjib Panda, Abhishek Mandal, Prabir Ghosh, Goutam Kumar Lahiri
The impact of the {Ru(acac)2} (acac- = acetylacetonate) framework on the transformations of C-H and C-H/C-C bonds of coordinated β-diketiminate and ketodiimine scaffolds, respectively, has been addressed. It includes the following transformations involving {Ru(acac)2} coordinated β-diketiminate in 1 and ketodiimine in 2 with the simultaneous change in metal oxidation state: (i) insertion of oxygen into the C(sp2)-H bond of β-diketiminate in 1, leading to the metalated ketodiimine in 2 and (ii) Bronsted acid (CH3COOH) assisted cleavage of unstrained C(sp2)-C(sp2)/C═N bonds of chelated ketodiimine (2) with the concomitant formation of intramolecular C-N bond in 3, as well as insertion of oxygen into the C(sp3)-H bond of 2 to yield -CHO function in 4 (-CH3 → -CHO)...
November 30, 2017: Inorganic Chemistry
Izabella Krucińska, Bogusława Żywicka, Agnieszka Komisarczyk, Maria Szymonowicz, Stanisława Kowalska, Ewa Zaczyńska, Marcin Struszczyk, Anna Czarny, Piotr Jadczyk, Barbara Umińska-Wasiluk, Zbigniew Rybak, Marek Kowalczuk
In response to the demand for new implant materials characterized by high biocompatibility and bioresorption, two prototypes of fibrous nanocomposite implants for osseous tissue regeneration made of a newly developed blend of poly(l-lactide-co-glycolide) (PLGA) and syntheticpoly([R,S]-3-hydroxybutyrate), PLGA/PHB, have been developed and fabricated. Afibre-forming copolymer of glycolide and l-lactide (PLGA) was obtained by a unique method of synthesis carried out in blocksusing Zr(AcAc)₄ as an initiator. The prototypes of the implants are composed of three layers of PLGA or PLGA/PHB, nonwoven fabrics with a pore structure designed to provide the best conditions for the cell proliferation...
November 29, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Foteini E Kakaroni, Alexandra Collet, Eirini Sakellari, Demetrios I Tzimopoulos, Milosz Siczek, Tadeusz Lis, Mark Murrie, Constantinos J Milios
The solvothermal reaction between Cr(acac)3, MCl2·6H2O (M = Ni, Co) and 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (H2L), under basic conditions, led to the synthesis of the heterometallic heptanuclear clusters [MCr(HLzw)6(HL)6]·3Cl (M = Ni, 1; Co, 2), with the nickel analogue displaying an S = 9/2 spin ground-state.
November 29, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Lujia Mao, Rüdiger Bertermann, Katharina Emmert, Kálmán J Szabó, Todd B Marder
An efficient methodology for the synthesis of vinyl-, allyl-, and (E)-2-boryl allylboronates from propargylic alcohols via Cu-catalyzed borylation under mild conditions is reported. In the presence of commercially available Cu(OAc)2 or Cu(acac)2 and Xantphos, the reaction affords the desired products in up to 92% yield with a broad substrate scope (43 examples). Isolation of an allenyl boronate as the reaction intermediate suggests that an insertion-elimination-type reaction, followed by borylcupration, is involved in the borylation of propargylic alcohols...
November 28, 2017: Organic Letters
Goutam Kumar Lahiri
The doubly deprotonated form L2 of indigo = H2L can bind two [Ru(acac)2] complex fragments in the cis (1) and trans configuration (2), as evident from crystal structure analysis. While the latter type of N,O; N/,O/ coordination has been observed earlier, e.g. with [Ru(bpy)2]2+, leading to two equivalent six-membered ring chelates, the cis arrangement in 1 is observed here for the first time in a dinuclear complex, producing one five-membered ring chelate with N,N/ coordination and one seven-membered chelate with O,O/ coordination...
November 22, 2017: Chemistry, An Asian Journal
Jose R Cabrero-Antonino, Rosa Adam, Kathrin Junge, Matthias Beller
The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac)3 and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, L1), in the presence of Al(OTf)3 as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1H-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids...
September 1, 2017: Chemical Science
Azliana Abu Bakar Sajak, Ahmed Mediani, Maulidiani, Nur Sumirah Mohd Dom, Chandradevan Machap, Muhajir Hamid, Amin Ismail, Alfi Khatib, Faridah Abas
BACKGROUND: Ipomoea aquatica (locally known as "kangkung") has previously been reported to have hypoglycemic activities on glucose level in diabetes patients. However, the effect of I. aquatica ethanolic extract on the metabolites in the body has remained unknown. PURPOSE: This study provides new insights on the changes of endogenous metabolites caused by I. aquatica ethanolic extract and improves the understanding on the therapeutic efficacy and mechanism of I...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Atsuya Koizumi, Takuya Hasegawa, Atsushi Itadani, Kenji Toda, Taoyun Zhu, Mineo Sato
In the title complex, di-aqua-(1H-imidazole-κN(3))(nitrato-κ(2)O,O')bis-(4-oxo-pent-2-en-2-olato-κ(2)O,O')lanthanum(III), [La(C5H7O2)2(NO3)(C3H4N2)(H2O)2], the La atom is coordinated by eight O atoms of two acetyl-acetonate (acac) anions acting as bidentate ligands, two water mol-ecule as monodentate ligands, one nitrate anions as a bidentate ligand and one N atom of an imidazolate (ImH) molecule as a monodentate ligand. Thus, the coordination number of the La atom is nine in a monocapped square anti-prismatic polyhedron...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Yiping Shi, Paul C J Kamer, David J Cole-Hamilton, Michelle Harvie, Emma F Baxter, Kate J C Lim, Peter Pogorzelec
The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ε-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield...
October 1, 2017: Chemical Science
Xiaomeng Wang, Xin Wang, Zhongbo Wei, Shujuan Zhang
Cyanobacteria blooming is a serious environmental issue throughout the world. Removal of cyanobacterial cells from surface water with controlled release of cyanobacterial organic matter (COM), especially toxic microcystins (MCs), would potentially reduce the processing burden in follow-up water treatment. Coagulation is a key technique in water treatment. Herein, the potential application of a novel titanium xerogel coagulant (TXC) was evaluated for the treatment of cyanobacteria-laden water in terms of cyanobacteria removal efficiency, variation of cell viability, the release and evolution of COM in the floc accumulation and storage process...
October 30, 2017: Water Research
Josep Bonjoch, Ben Bradshaw, Mar Saladrigas, Caroline Bosch, Gisela V Saborit
An unprecedented hydrogen atom transfer-based C-C coupling reaction between alkenes and ketones using Fe(acac)3 and PhSiH3 in EtOH is described. This mild protocol features high site-selectivity and allows for the construction of sterically congested structures containing tertiary alcohols and quaternary centers. The overall process introduces a novel strategic bond disconnection for ring-closing reactions.
November 8, 2017: Angewandte Chemie
Juan Téllez, Albert Gallen, Joaquina Ferrer, Fernando J Lahoz, Pilar García-Orduña, Antoni Riera, Xavier Verdaguer, Daniel Carmona, Arnald Grabulosa
The reaction of the acetylacetonates [(η(5)-C5Me5)M(acac)Cl] with (SP)-[HMaxPhos][BF4] afforded cationic complexes with the formula (SM,RP)-[(η(5)-C5Me5)MCl(MaxPhos)][BF4] (M = Rh (1), Ir (2)). The reaction of (SP)-MaxPhos with [RuCl(μ-Cl)(η(6)-p-MeC6H4(i)Pr)]2 and NH4X afforded (SRu,RP)-[(η(6)-p-MeC6H4(i)Pr)RuCl(MaxPhos)][X] (X = BF4 (3), PF6 (3')). The complexes have been completely characterized by analytical and spectroscopic means, including the determination of the crystal structures of 1, 2 and 3'...
November 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Kenji Sugisaki, Kazuo Toyota, Kazunobu Sato, Daisuke Shiomi, Takeji Takui
Spin-orbit contributions to the zero-field splitting (ZFS) tensor (D(SO) tensor) of M(III)(acac)3 complexes (M = V, Cr, Mn, Fe and Mo; acac = acetylacetonate anion) are evaluated by means of ab initio (a hybrid CASSCF/MRMP2) and DFT (Pederson-Khanna (PK) and natural orbital-based Pederson-Khanna (NOB-PK)) methods, focusing on the behaviour of DFT-based approaches to the D(SO) tensors against the valence d-electron configurations of the transition metal ions in octahedral coordination. Both the DFT-based approaches reproduce trends in the D tensors...
November 3, 2017: Physical Chemistry Chemical Physics: PCCP
Mohd Asif Ansari, Abhishek Mandal, Katharina Beyer, Alexa Paretzki, Brigitte Schwederski, Wolfgang Kaim, Goutam Kumar Lahiri
The redox-active ligand 5,7,12,14-tetraazapentacene-6,13-quinone = L forms structurally characterised compounds with three (1) or four (2) [Ru(acac)2] complex fragments in which each of the metals is N,O-chelated. The new tris- and tetrakis-bidentate chelate compounds exhibit ruthenium centres bridged at about 4 Å by quinone O atoms which are then situated across the pentacene π system at about 6-8 Å distance. Several electron transfer processes were observed by voltammetry (CV, DPV) and the intermediates identified by EPR and UV-Vis-NIR spectroelectrochemistry...
November 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sem Raj Tamang, Michael Findlater
We report an operationally convenient room temperature hydroboration of aldehydes and ketones employing Fe(acac)3 as precatalyst. The hydroboration of aldehydes and ketones proceeded efficiently at room temperature to yield, after work up, 1° and 2° alcohols; chemoselective hydroboration of aldehydes over ketones is attained under these conditions. We propose a sigma bond metathesis mechanism in which an Fe-H intermediate is postulated to be a key reactive species.
October 30, 2017: Journal of Organic Chemistry
Aditi Bhattacherjee, Chaitanya Das Pemmaraju, Kirsten Schnorr, Andrew R Attar, Stephen R Leone
Molecular triplet states constitute a crucial gateway in the photochemical reactions of organic molecules by serving as a reservoir for the excess electronic energy. Here, we report the remarkable sensitivity of soft X-ray transient absorption spectroscopy for following the intricate electronic structure changes accompanying the non-adiabatic transition of an excited molecule from the singlet to the triplet manifold. Core-level X-ray spectroscopy at the carbon-1s K-edge (284 eV) is applied to identify the role of the triplet state (T1, (3)ππ*) in the ultraviolet-induced photochemistry of pentane-2,4-dione (acetylacetone, AcAc)...
November 9, 2017: Journal of the American Chemical Society
Jason Hon, Michelle S Hwang, Meara A Charnetzki, Issra J Rashed, Patrick B Brady, Sarah Quillin, Marvin W Makinen
Protein tyrosine phosphatases (PTPases) are a prominent focus of drug design studies because of their roles in homeostasis and disorders of metabolism. These studies have met with little success because (1) virtually all inhibitors hitherto exhibit only competitive behavior and (2) a consensus sequence H/V-C-X5-R-S/T characterizes the active sites of PTPases, leading to low specificity of active site directed inhibitors. With protein tyrosine phosphatase-1B (PTP1B) identifed as the target enzyme of the vanadyl (VO(2+)) chelate bis(acetylacetonato)oxidovanadium(IV) [VO(acac)2] in 3T3-L1 adipocytes [Ou et al...
December 2017: Journal of Biological Inorganic Chemistry: JBIC
Kamna Sharma, Rajendran Antony, Alok Ch Kalita, Sandeep Kumar Gupta, Paul Davis, Ramaswamy Murugavel
[Ti(acac)2(O(i)Pr)2] reacts with tert-butylphosphonic acid to yield a series of titanium organophosphonates such as tetranuclear [Ti4(acac)4(μ-O)2(μ-(t)BuPO3)2(μ-(t)BuPO3H)4]·2CH3CN (1), pentanuclear [Ti5(acac)5(μ-O)2(O(i)Pr)(μ-(t)BuPO3)4(μ-(t)BuPO3H)2] (2), hexanuclear [Ti6(acac)6(μ-O)2(O(i)Pr)2(μ-(t)BuPO3)6] (3), or [Ti6(acac)6(μ-O)3(O(i)Pr)(μ-(t)BuPO3)5(μ-(t)BuPO3H)]·2CH3CN (4). The isolation of each of these products in pure form depends on the molar ratio of the reactants or the solvent medium...
November 6, 2017: Inorganic Chemistry
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