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Susanta Hazra, Ricardo Meyrelles, Adilia Januário Charmier, Patrícia Rijo, M Fátima C Guedes da Silva, Armando J L Pombeiro
The Schiff base H2L(1) [N,N'-ethylenebis(3-methoxysalicylaldimine)] or H2L(2) [N,N'-ethylenebis(3-ethoxysalicylaldimine)] was reacted with MCl2·xH2O and SnCl4·5H2O to afford the supramolecular heterobimetallic systems (H2ED)(2+)·2[ML]·[SnCl6](2-) [M = Cu, L = L(1) (1), L = L(2) (2); M = Ni, L = L(1) (3), L = L(2) (4); ED = 1,2-ethylenediamine], whose structures were established by single crystal X-ray analyses. Each structure includes different entities, viz. a mononuclear [CuL]/[NiL] neutral complex (coformer), a hexachlorostannate dianion [SnCl6](2-), a 1,2-ethylenediammonium dication (H2ED(2+)) and, only in 2 and 4, a methanol molecule...
October 25, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Shuai Gao, Man Pan, Yong Zheng, Yichao Huang, Qingyun Zheng, Demeng Sun, Lining Lu, Xiaodan Tan, Xianglong Tan, Huan Lan, Jiaxing Wang, Tian Wang, Jiawei Wang, Lei Liu
Racemic or quasi-racemic crystallography recently emerges as a useful technology for solution of the crystal structures of biomacromolecules. It remains unclear to what extent the biomacromolecules of opposite handedness can differ from each other in racemic or quasi-racemic crystallography. Here we report a finding that monomeric d-ubiquitin (Ub) has propensity to cocrystallize with different dimers, trimers, and even a tetramer of l-Ub. In these cocrystals the unconnected monomeric d-Ubs can self-assemble to form pseudomirror images of different oligomers of l-Ub...
October 21, 2016: Journal of the American Chemical Society
Scott J Hughes, Leanne Barnard, Katayoun Mottaghi, Wolfram Tempel, Tetyana Antoshchenko, Bum Soo Hong, Abdellah Allali-Hassani, David Smil, Masoud Vedadi, Erick Strauss, Hee-Won Park
The potent antistaphylococcal activity of N-substituted pantothenamides (PanAms) has been shown to at least partially be due to the inhibition of Staphylococcus aureus's atypical type II pantothenate kinase (SaPanKII), the first enzyme of coenzyme A biosynthesis. This mechanism of action follows from SaPanKII having a binding mode for PanAms that is distinct from those of other PanKs. To dissect the molecular interactions responsible for PanAm inhibitory activity, we conducted a mini SAR study in tandem with the cocrystallization of SaPanKII with two classic PanAms (N5-Pan and N7-Pan), culminating in the synthesis and characterization of two new PanAms, N-Pip-PanAm and MeO-N5-PanAm...
September 9, 2016: ACS Infectious Diseases
Andrew J E Duncan, Roxanne L Dudovitz, Shawna J Dudovitz, Jelena Stojaković, S V Santhana Mariappan, Leonard R MacGillivray
We describe a [2+2] cross-photocycloaddition of the anticancer drug 5-fluorouracil in the solid state that proceeds regioselectively and in quantitative yield. The photocycloaddition occurs in a cocrystal with trans-2,2'-bis(pyridyl)ethylene.
October 19, 2016: Chemical Communications: Chem Comm
Prabhakar Panzade, Giridhar R Shendarkar
Pharmaceutical cocrystal is an emerging approach to tailor physicochemical and mechanical properties of drug substances. Cocrystals are composed of API and pharmaceutically acceptable coformer. It can be used to address the solubility, dissolution, mechanical properties, stability of drugs. This review discusses introduction to cocrystal, preparation and characterization, what USFDA says on cocrystal and role of Hansen solubility parameter to predict cocrystal. The effect of cocrystal on drug properties, dependence of cocrystal solubility on pH, concept of drug-drug cocrystal and aerosil 200 as novel cocrystal former and impact of cocrystal on drug pharmacokinetic has also been presented in this review along with highly selected examples of cocrystals...
October 18, 2016: Current Drug Delivery
Nis Halland, Jörg Czech, Werngard Czechtizky, Andreas Evers, Markus Follmann, Markus Kohlmann, Herman A Schreuder, Christopher Kallus
Previously disclosed TAFIa inhibitors having a urea zinc-binding motif were used as the starting point for the development of a novel class of highly potent inhibitors having a sulfamide zinc-binding motif. High-resolution X-ray cocrystal structures were used to optimize the structures and reveal a highly unusual sulfamide configuration. A selected sulfamide was profiled in vitro and in vivo and displayed a promising ADMET profile.
October 17, 2016: Journal of Medicinal Chemistry
Yan-Song Zheng, Hai-Tao Feng, Jun Luo, Jia-Bin Xiong, Wen-Fang Feng, Desuo Yang
Tetraphenylethylene (TPE) and its derivatives are the most typical and most widely studied organic compounds with aggregation-induced emission (AIE) characteristics. Due to their propeller-like structures, V-like clefts exist between the aryl rings, making them promising as host compounds. However, such possibility is seldom explored. Here, we reported for the first time that TPE derivatives (TPE-Pys) bearing two or four pyridine rings at the para-position of the phenyl rings could selectively include triangular (Δ-like) m-phthalic acid from a mixture of o-, m- and p-phthalic acids due to their shape complementary to offer host-guest cocrystals, which showed redder emission than TPE-Pys themselves...
October 14, 2016: Chemistry: a European Journal
Fumitoshi Kaneko, Naoki Seto, Shuma Sato, Aurel Radulescu, Maria Maddalena Schiavone, Jürgen Allgaier, Koichi Ute
Syndiotactic polystyrene (sPS) is a crystalline polymer which has a unique property; it is able to form cocrystals with a wide range of chemical compounds, in which the guest molecules are confined in the vacancies of the host sPS crystalline region. Recently, it has been found that even polyethylene glycol oligomers with a molecular weight of more than several hundreds can be introduced into the sPS crystalline region. It is quite important to know how such a long-chain molecule is stored in the host sPS lattice...
October 1, 2016: Journal of Applied Crystallography
Weigang Zhu, Lingyun Zhu, Lingjie Sun, Yonggang Zhen, Huanli Dong, Zhixiang Wei, Wenping Hu
The spectroscopic and photophysical properties of organic materials in the solid-state are widely accepted as a result of their molecular packing structure and intermolecular interactions, such as J- and H-aggregation, charge-transfer (CT), excimer and exciplex. However, in this work, we show that Spe-F4 DIB cocrystals (SFCs) surprisingly retain the energy levels of photoluminescence (PL) states of Spe crystals, despite a significantly altered molecular packing structure after cocrystallization. In comparison, Npe-F4 DIB cocrystals (NFCs) with new spectroscopic states display different spectra and photophysical behaviors as compared with those of individual component crystals...
October 10, 2016: Angewandte Chemie
Minsup Kim, Art E Cho
A great number of GPCR crystal structures have been solved in recent years, enabling GPCR-targeted drug discovery using structure-based approaches such as docking. GPCRs generally have wide and open entrances to the binding sites, which render the binding sites readily accessible to solvent. GPCRs are also populated with hydrophilic residues in the extracellular regions. Thus, including solvent and polarization effects can be important for accurate GPCR docking. To test this hypothesis, a new docking protocol which incorporates quantum mechanical/molecular mechanical (QM/MM) calculations along with an implicit solvent model is developed...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
Anilkumar Gunnam, Kuthuru Suresh, Ramesh Ganduri, Ashwini Nangia
The transformation of zwitterionic Sparfloxacin (SPX) to the neutral form is achieved by cocrystallization. Neutral forms of drugs are important for higher membrane permeability, while zwitterions are more soluble in water. The twin advantages of higher solubility/dissolution rate and good stability of neutral SPX are achieved in a molecular cocrystal compared to its zwitterionic SPX hydrate. The amine-phenol supramolecular synthon drives cocrystal formation, with the paraben ester acting as a "proton migrator" for the ionic to neutral transformation...
October 18, 2016: Chemical Communications: Chem Comm
Lei Zhang, Ji-Zhou Wu, Sheng-Li Jiang, Yi Yu, Jun Chen
By employing a first-principles method, we conducted a thorough study on a novel cocrystal explosive 1 : 1 NTO : TZTN and gained insight into the interaction-structure-property interrelationship. Mulliken bond orders, Hirshfeld surfaces, intermolecular binding energies, packing coefficients, and oxygen balance were calculated to analyze the intermolecular interactions and structures of the cocrystal explosive. The cocrystallization of NTO and TZTN molecules enhances the intermolecular binding force, which drives the synthesis of the cocrystal...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Eric Bosch
Weak interactions between organic molecules are important in solid-state structures where the sum of the weaker interactions support the overall three-dimensional crystal structure. The sp-C-H...N hydrogen-bonding interaction is strong enough to promote the deliberate cocrystallization of a series of diynes with a series of dipyridines. It is also possible that a similar series of cocrystals could be formed between molecules containing a terminal alkyne and molecules which contain carbonyl O atoms as the potential hydrogen-bond acceptor...
October 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Xiao Qing Cai, Bei Tian, Jian Nan Zhang, Zhi Min Jin
A fixed hydrogen-bonding motif with a high probability of occurring when appropriate functional groups are involved is described as a `supramolecular hydrogen-bonding synthon'. The identification of these synthons may enable the prediction of accurate crystal structures. The rare chiral hydrogen-bonding motif R5(3)(10) was observed previously in a cocrystal of 2,4,6-trichlorophenol, 2,4-dichlorophenol and dicyclohexylamine. In the title solvated salt, 2C4H12N(+)·C6H3Cl2O(-)·(C6H3Cl2O(-)·C6H4Cl2O)·2C4H8O, five components, namely two tert-butylammonium cations, one 2,4-dichlorophenol molecule, one 2,4-dichlorophenolate anion and one 2,6-dichlorophenolate anion, are bound by N-H...
October 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Robb Welty, Kathleen B Hall
The tertiary structure of the GTPase center (GAC) of 23S ribosomal RNA (rRNA) as seen in cocrystals is extremely compact. It is stabilized by long-range hydrogen bonds and nucleobase stacking and by a triloop that forms within its three-way junction. Its folding pathway from secondary structure to tertiary structure has not been previously observed, but it was shown to require Mg(2+) ions in equilibrium experiments. The fluorescent nucleotide 2-aminopurine was substituted at selected sites within the 60-nt GAC...
September 29, 2016: Journal of Molecular Biology
Ken-Peng Song, Fu-de Ren, Shu-Hai Zhang, Wen-Jing Shi
A molecular dynamics method was employed to study the binding energies associated with the cocrystallization (at selected crystal planes) of either 1,3,5-triamino-2,4,6-trinitro-benzene (TATB), 1,1-diamino-2,2-dinitroethylene, 3-nitro-1,2,4-triazol-5-one (TATB, FOX-7, and NTO, respectively, all of which are explosives), or N,N-dimethylformamide (DMF, a nonenergetic solvent) in various molar ratios with 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane in its α and β conformations (α-HMX and β-HMX, respectively)...
October 2016: Journal of Molecular Modeling
Lioudmila V Loukachevitch, Barbara A Bensing, Hai Yu, Jie Zeng, Xi Chen, Paul M Sullam, T M Iverson
Streptococcus sanguinis is a leading cause of bacterial infective endocarditis, a life-threatening infection of heart valves. S. sanguinis binds to human platelets with high avidity, and this adherence is likely to enhance virulence. Previous studies suggest that a serine-rich repeat adhesin termed SrpA mediates the binding of S. sanguinis to human platelets via its interaction with sialoglycans on the receptor GPIbα. However, in vitro binding assays with SrpA and defined sialoglycans failed to identify specific high-affinity ligands...
October 11, 2016: Biochemistry
Weigang Zhu, Lingyun Zhu, Ye Zou, Yishi Wu, Yonggang Zhen, Huanli Dong, Hongbing Fu, Zhixiang Wei, Qiang Shi, Wenping Hu
No abstract text is available yet for this article.
September 2016: Advanced Materials
Sunny Bhardwaj, Maya Lipert, Annette Bak
Poor aqueous solubility of a majority of new small molecule chemical entities is a significant challenge in drug discovery since considerably high exposures are often required to enable pharmacokinetic, pharmacology, and toxicology studies. Pharmaceutical cocrystals have received considerable attention in recent years owing to their potential to improve the physicochemical properties and in vivo performance of poorly soluble drugs. However, physical instability in supersaturated solution/suspension formulations is a major concern for their use in preclinical studies...
September 21, 2016: Journal of Pharmaceutical Sciences
Jenniffer I Arenas-García, Dea Herrera-Ruiz, Hugo Morales-Rojas, Herbert Höpfl
The thermal behavior, phase stability, indicative stability and intrinsic dissolution rates of a series of cocrystals and cocrystal hydrates derived from the pharmaceutically active ingredient acetazolamide (ACZ) and 2-aminobenzamide (2ABAM), 2,3-dihydroxybenzoic acid (23DHBA), 2-hydroxybenzamide (2HBAM), 4-hydroxybenzoic acid (4HBA), nicotinamide (NAM) and picolinamide (PAM) as cocrystal formers have been evaluated. Upon heating in an inert atmosphere most of the cocrystals tested demonstrated first the elimination of the crystal former, followed by ACZ degradation...
September 17, 2016: European Journal of Pharmaceutical Sciences
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