Showing papers in "ChemistryOpen in 2016"
TL;DR: This Review will focus on the key developments towards chemical O‐glycosylations in the current century, including synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosidic bonds.
Abstract: The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo- and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O-glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.
97 citations
TL;DR: The simple and fast electrostatic assembly of cellulase (CEL) and low‐priced silica‐coated magnetic nanoparticles, which demonstrates stable enzyme bonding and excellent colloidal stability, could be sustained over ten magnetic recycling steps.
Abstract: The constant increase in the number of sustainable products
on the global markets demands new biotechnological processing
strategies such as the purification and recovery of biocatalysts.
Superparamagnetic iron oxide nanoparticles exhibit excellent
recovery properties as carrier materials in enzyme catalysis.
We present the simple and fast electrostatic assembly of
cellulase (CEL) and low-priced silica-coated magnetic nanoparticles,
which demonstrates stable enzyme bonding and excellent
colloidal stability. The high CEL loading (0.43 gg1), without
leaching of biocatalyst and high recovery yields (75 %),
could be sustained over ten magnetic recycling steps. The
highlight of this study is the preservation of a high enzymatic
activity and, therefore, the outstandingly high lifecycle stability.
51 citations
TL;DR: It is concluded that it is not justified to rely on fortunate error compensation, as the main inconsistencies can be cured by modern correction schemes which clearly outperform the plain mean‐field methods.
Abstract: In quantum chemical computations the combination of Hartree–Fock or a density functional theory (DFT) approximation with relatively small atomic orbital basis sets of double-zeta quality is still widely used, for example, in the popular B3LYP/6-31G* approach. In this Review, we critically analyze the two main sources of error in such computations, that is, the basis set superposition error on the one hand and the missing London dispersion interactions on the other. We review various strategies to correct those errors and present exemplary calculations on mainly noncovalently bound systems of widely varying size. Energies and geometries of small dimers, large supramolecular complexes, and molecular crystals are covered. We conclude that it is not justified to rely on fortunate error compensation, as the main inconsistencies can be cured by modern correction schemes which clearly outperform the plain mean-field methods.
51 citations
TL;DR: This Review focuses on the development and use of modern nuclear magnetic resonance (NMR) techniques to dissect binding events, taking into account as indispensable tools to provide a complete picture of protein–glycoconjugate binding mechanisms related to biomedicine applications against infectious diseases.
Abstract: Understanding the dynamics of protein-ligand interactions, which lie at the heart of host-pathogen recognition, represents a crucial step to clarify the molecular determinants implicated in binding events, as well as to optimize the design of new molecules with therapeutic aims. Over the last decade, advances in complementary biophysical and spectroscopic methods permitted us to deeply dissect the fine structural details of biologically relevant molecular recognition processes with high resolution. This Review focuses on the development and use of modern nuclear magnetic resonance (NMR) techniques to dissect binding events. These spectroscopic methods, complementing X-ray crystallography and molecular modeling methodologies, will be taken into account as indispensable tools to provide a complete picture of protein-glycoconjugate binding mechanisms related to biomedicine applications against infectious diseases.
48 citations
TL;DR: Cycling into closed assemblies is the most recurrent approach to realize the noncovalent synthesis of discrete, well‐defined nanostructures, and several examples described in the literature in which cycles of different sizes are studied by diverse solution or surface characterization techniques are discussed.
Abstract: Cyclization into closed assemblies is the most recurrent approach to realize the noncovalent synthesis of discrete, well-defined nanostructures. This review article particularly focuses on the noncovalent synthesis of monocyclic hydrogen-bonded systems that are self-assembled from a single molecule with two binding-sites. Taking advantage of intramolecular binding events, which are favored with respect to intermolecular binding in solution, can afford quantitative amounts of a given supramolecular species under thermodynamic control. The size of the assembly depends on geometric issues such as the monomer structure and the directionality of the binding interaction, whereas the fidelity achieved relies largely on structural preorganization, low degrees of conformational flexibility, and templating effects. Here, we discuss several examples described in the literature in which cycles of different sizes, from dimers to hexamers, are studied by diverse solution or surface characterization techniques.
41 citations
TL;DR: These compounds represent the first oxime esters from nature, isolated from the scale‐up fermentation broth of B. vibrans, which exhibited significant pancreatic lipase inhibitory activity and cytotoxicities against five human cancer cell lines.
Abstract: A variety of novel natural products with significant bioactivities are produced by the basidiomycete Boreostereum vibrans. In the present study, we describe 16 novel natural oximes and oxime esters with a vibralactone backbone, vibralactoximes, which were isolated from the scale-up fermentation broth of B. vibrans. Their structures were determined through extensive spectroscopic analyses. These compounds represent the first oxime esters from nature. The hypothetical biosynthetic pathway of these compounds was also proposed. Seven compounds exhibited significant pancreatic lipase inhibitory activity, while ten compounds exhibited cytotoxicities against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480), with IC50 values comparable with those of cisplatin.
39 citations
TL;DR: A ceria–vanadia/silica (Ce–V/SiO2) heterogeneous catalyst was designed and used for the green and efficient synthesis of 2‐amino‐3‐cyano‐4H‐pyran derivatives and offers a number of advantages including decreased reaction times, mild conditions, high yields, operational simplicity, and environmentally benign and simple work‐up procedures.
Abstract: We designed a ceria-vanadia/silica (Ce-V/SiO2) heterogeneous catalyst and used it for the green and efficient synthesis of 2-amino-3-cyano-4H-pyran derivatives. The green reaction was a multicomponent one-pot condensation of 5,5-dimethylcyclohexane-1,3-dione, aromatic aldehyde, and malononitrile in an eco-compatible solvent (ethanol). The catalyst was synthesized and fully characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The reported procedure offers a number of advantages including decreased reaction times, mild conditions, high yields, operational simplicity, and environmentally benign and simple work-up procedures. Furthermore, the catalyst is economical, fully recyclable, and reusable for over five runs while preserving its high activity. The synthesized 2-amino-3-cyano-4H-pyran products can later be used for pharmaceutical purposes.
36 citations
TL;DR: The g‐C3N4‐combined 3 D nanoporous/nanotubular structure provides a platform with significant visible‐light response in photocatalytic applications and shows a strong enhancement for photoelectrochemical and bias‐free H2 evolution.
Abstract: Aligned TiO2 nanotube layers (TiNTs) grown by self-organizing anodization of a Ti-substrate in a fluoride-based electrolyte were decorated with graphitic-phase C3N4 (g-C3N4) via a facile chemical vapor deposition approach. In comparison with classical TiO2 nanotubes (anatase), the g-C3N4/TiNTs show an onset of the photocurrent at 2.4 eV (vs. 3.2 eV for anatase) with a considerably high photocurrent magnitude in the visible range. After further decoration with Pt nanoparticles, we obtained a visible-light responsive platform that showed, compared with g-C3N4-free TiNTs, a strong enhancement for photoelectrochemical and bias-free H2 evolution (15.62 μLh−1 cm−2), which was almost a 98-fold increase in the H2 production rate of TiNTs (0.16 μLh−1 cm−2). In a wider context, the g-C3N4-combined 3 D nanoporous/nanotubular structure thus provides a platform with significant visible-light response in photocatalytic applications.
34 citations
TL;DR: A facile one‐pot approach for preparing hierarchical nanowire‐networks of hollow polymer@Pd nanospheres is reported, and the catalyst can be recycled via simple filtration and washing, maintaining its high activity owing to the micrometer‐sized hierarchical structure of the nanomaterial.
Abstract: A facile one-pot approach for preparing hierarchical nanowire-networks of hollow polymer@Pd nanospheres is reported. First, polymer@Pd hollow nanospheres were produced through metal-complexation-induced phase separation with functionalized graft copolymers and subsequent self-assembly of PdNPs. The nanospheres hierarchically assembled into the nanowire-network upon drying. The Pd nanowire-network served as an active catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling reactions. As low as 500 μmol % Pd was sufficient for quantitative reactions, and the origin of the high activity is ascribed to the highly active sites originating from high-index facets, kinks, and coalesced structures. The catalyst can be recycled via simple filtration and washing, maintaining its high activity owing to the micrometer-sized hierarchical structure of the nanomaterial. The polymer@Pd nanosphere also served as a printable conductive ink for a translucent grid pattern with excellent horizontal conductivity (7.5×10(5) S m(-1)).
33 citations
TL;DR: A comprehensive reference table that graphically maps out the LUMO space covered by the leading families of electronaccepting aromatics, and a graphical summary of general trends in the π‐acidic space is expected to be both inspiring and quite useful in practice.
Abstract: Core-substituted naphthalenediimides (NDIs) attract increasing attention to bind, transport, and transform electrons, anions, anionic intermediates, and anionic transition states, and to shine as most colorful rainbow fluorophores. The energy level of their lowest unoccupied molecular orbital (LUMO) is decisive for many of these applications. Here, differential pulse voltammetry (DPV) measurements for a consistent series of NDIs are reported to extract exact LUMO levels under identical conditions. The influence of primary and secondary substituents in the core and on the primary imides is compared with general trends for the reliable prediction of LUMO levels in functional systems. Emphasis is on sulfur redox switches in the NDI core because of their frequent use as isostructural probes for π acidity. The same sulfur redox chemistry is expanded to perylenediimides (PDIs), and LUMO engineering is discussed in a broader context, including also fullerenes, aminonaphthalimides (ANIs), and aminoperyleneimides (APIs). The result is a comprehensive reference table that graphically maps out the LUMO space covered by the leading families of electronaccepting aromatics. This graphical summary of general trends in the π-acidic space is expected to be both inspiring and quite useful in practice.
28 citations
TL;DR: Solutions of 5-N-arylaminothiazoles containing pyridyl groups exhibited clear halochromism and halofluorism upon addition of Brønsted and Lewis acids and DFT calculations suggested that the spectral changes arise from the protonated group of the thiazoles in Et2O.
Abstract: Solutions of 5-N-arylaminothiazoles containing pyridyl groups exhibited clear halochromism and halofluorism upon addition of Bronsted and Lewis acids. The addition of triflic acid to solutions of 5-N-arylaminothiazoles in Et2O induced bathochromic shifts of the absorption and emission bands. DFT calculations suggested that the spectral changes arise from the protonation of the pyridyl group of the thiazoles in Et2O. Single-crystal X-ray diffraction analysis of a thiazole and its protonated form revealed the change of the conformation around the thiazole ring. The emission of white light was accomplished from a single fluorescent dye by adjusting the ratio of dye and B(C6F5)3, whereby the International Commission on Illumination coordinates showed a linear change from blue to orange.
TL;DR: A synthetic small‐molecule system designed to catch, displace, and release molecular cargo in solution under external control is reported, consisting of a bistable rotaxane that behaves as an acid–base controlled molecular shuttle, whose ring component bears a tether ending with a nitrile group.
Abstract: The transport of substrates is one of the main tasks of biomolecular machines in living organisms. We report a synthetic small-molecule system designed to catch, displace, and release molecular cargo in solution under external control. The system consists of a bistable rotaxane that behaves as an acid–base controlled molecular shuttle, whose ring component bears a tether ending with a nitrile group. The latter can be coordinated to a ruthenium complex that acts as the load, and dissociated upon irradiation with visible light. The cargo loading/unloading and ring transfer/return processes are reversible and can be controlled independently. The robust coordination bond ensures that the cargo remains attached to the device while the transport takes place.
TL;DR: In this paper, a broad set of enamines, indoles, β-keto esters, pyrroles, and anilines were nicely transformed into corresponding trifluoromethylthio (SCF3) compounds in good to high yields by diazo-triflone under copper catalysis via an electrophilic-type reaction.
Abstract: 2-Diazo-1-phenyl-2-((trifluoromethyl)sulfonyl)ethan-1-one (diazo-triflone) (2) is not only a building block but also a reagent. In this study, diazo-triflone, which was originally used for the synthesis of β-lactam triflones as a trifluoromethanesulfonyl (SO2CF3) building block under catalyst-free thermal conditions, is redisclosed as an effective electrophilic trifluoromethylthiolation reagent under copper catalysis. A broad set of enamines, indoles, β-keto esters, pyrroles, and anilines were nicely transformed into corresponding trifluoromethylthio (SCF3) compounds in good to high yields by diazo-triflone under copper catalysis via an electrophilic-type reaction. A coupling-type trifluoromethylthiolation reaction of aryl iodides was also realized by diazo-triflone in acceptable yields.
TL;DR: Three types of chloride‐conducting membranes based on polyvinyl chloride, commercial gelatin, and polyvinyldifluoride‐hexafluoropolymer are introduced and the structural properties, thermal stability, and electrochemical response of the membranes are studied to understand chloride migration and transport.
Abstract: Three types of chloride-conducting membranes based on polyvinyl chloride, commercial gelatin, and polyvinyldifluoride-hexafluoropolymer are introduced in this report. The polymers are mixed with chloride-containing salts, such as tetrabutylammonium chloride, and cast to form membranes. We studied the structural properties, thermal stability, and electrochemical response of the membranes to understand chloride migration and transport. Finally, the membranes are tested in a prototype solid-state chloride-ion battery setup. The feasibility of the membranes for their potential use in anion batteries is discussed.
TL;DR: In the absence of the amide moiety in NDI‐N, no self‐assembly was observed, indicating the fundamental role of H‐bonding in the self‐association process.
Abstract: In the present work, two new naphthalene diimide (NDI) amphiphiles, NDI-N and NDI-NA, were successfully synthesized and employed to investigate their self-assembly and optical properties. For NDI-NA, which contains an amide group, aggregation-induced emission enhancement (AIEE) was demonstrated in the presence of various ratios of methylcyclohexane (MCH) in chloroform, which led to the visual color changes. This new amide-containing NDI-NA amphiphile formed nanobelt structures in chloroform/MCH (10:90, v/v) and microcup-like morphologies in chloroform/MCH (5:95, v/v). The closure of these microcups led to the formation of vesicles and microcapsules. The structural morphologies gained from the solvophobic control of NDI-NA were confirmed by various complementary techniques such as infrared spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. In the absence of the amide moiety in NDI-N, no self-assembly was observed, indicating the fundamental role of H-bonding in the self-association process.
TL;DR: T theoretical studies of one‐dimensional extended graphdiyne nanowires using first‐principle calculations are presented to provide a deeper understanding of the structural, electronic, and transport properties of this new species.
Abstract: Graphdiyne and derivatives with delocalized π-electron systems are of particular interest owing to their structural, electronic, and transport properties, which are important for potential applications in next-generation electronics. Inspired by recently obtained extended graphdiyne nanowires, explorations of the modulation of the band gap and carrier mobility of this new species are still needed before application in device fabrication. To provide a deeper understanding of these issues, herein we present theoretical studies of one-dimensional extended graphdiyne nanowires using first-principle calculations. Modulation of the electronic properties of the extended graphdiyne nanowire was investigated systemically by considering several chemical and physical factors, including electric field, chemical functionalization, and carbo-merization. The band gap was observed to increase upon application of an electric field parallel to the plane of the synthesized graphdiyne nanowire in a non-periodic direction. Although chemical functionalization and carbo-merization caused the band gaps to decrease, the semiconducting property of the nanowires was preserved. Band gap engineering of the extended graphdiyne nanowires was explored regarding the field strength and the number of -C≡C- units in the carbon chain fragments. The charge carrier mobility of chemically functionalized and carbo-merized extended graphdiyne nanowires was also calculated to provide a comparison with pristine nanowire. Moreover, crystal orbital analysis was performed in order to discern the electronic and charge transport properties of the extended graphdiyne nanowires modified by the aforementioned chemical and physical factors.
TL;DR: The QSRR approach has been used to predict the effect of the structure of the substrate, nucleophile, and catalyst, as well as the experimental conditions, on the enantioselectivity, and trends to improve the experimental results could be found without engaging in a long‐term empirical investigation.
Abstract: Enamides with a free NH group have been evaluated as nucleophiles in chiral Bronsted acid-catalyzed enantioselective α-amidoalkylation reactions of bicyclic hydroxylactams for the generation of quaternary stereocenters. A quantitative structure-reactivity relationship (QSRR) method has been developed to find a useful tool to rationalize the enantioselectivity in this and related processes and to orient the catalyst choice. This correlative perturbation theory (PT)-QSRR approach has been used to predict the effect of the structure of the substrate, nucleophile, and catalyst, as well as the experimental conditions, on the enantioselectivity. In this way, trends to improve the experimental results could be found without engaging in a long-term empirical investigation.
TL;DR: Crystal structures of two key zinc complexes evidence variations in triazole coordination that mirror the solution‐phase behaviour of these systems, and introduce a second fluorophore greatly extends fluorescence lifetimes.
Abstract: Fluorescent molecular probes for metal ions have a raft of potential applications in chemistry and biomedicine. We report the synthesis and photophysical characterisation of 1,8-disubstituted-cyclam/naphthalimide conjugates and their zinc complexes. An efficient synthesis of 1,8-bis-(2-azidoethyl)cyclam has been developed and used to prepare 1,8-disubstituted triazolyl-cyclam systems, in which the pendant group is connected to triazole C4. UV/Vis and fluorescence emission spectra, zinc binding experiments, fluorescence quantum yield and lifetime measurements and pH titrations of the resultant bis-naphthalimide ligand elucidate a complex pattern of photophysical behaviour. Important differences arise from the inclusion of two fluorophores in the one probe and from the variation of triazole substitution pattern (dye at C4 vs. N1). Introducing a second fluorophore greatly extends fluorescence lifetimes, whereas the altered substitution pattern at the cyclam amines exerts a major influence on fluorescence output and metal binding. Crystal structures of two key zinc complexes evidence variations in triazole coordination that mirror the solution-phase behaviour of these systems.
TL;DR: The largest MP database (experimental value) of globally approved drugs and discontinued drugs is constructed and it is indicated that the MWs and Clog P values of most drugs in the optimal MP range were not more than 500 and 5, respectively, implying the MP distribution criterion was in accordance with Lipinski's rule of five.
Abstract: The melting point (MP), an easily accessible physical parameter, has considerable potential for the judgment of drug-like properties. However, to the best of our knowledge, there are no useful guidelines for understanding the relationship between the MP and drug-like properties. To this end, we have constructed the largest MP database (experimental value) of globally approved drugs (3164 organic small-molecule drugs) and discontinued drugs (417 organic small-molecule drugs) and subsequently extracted six subdatabases from the whole approved database and two subdatabases from the discontinued database. The MP distribution statistics and analysis of approved drugs reveal five noteworthy observations; moreover, the MP distribution statistics and analysis of discontinued drugs further supplement these criteria. In addition, the comparison of molecular weight (MW) versus MP and Clog P versus MP distributions of different classes of approved drugs indicated that the MWs and Clog P values of most drugs in the optimal MP range were not more than 500 and 5, respectively, implying the MP distribution criterion was in accordance with Lipinski's rule of five.
TL;DR: A new synthetic methodology of water‐soluble gold and silver nanoparticles (AuNPs @TC and AgNPs@TC), using the antibiotic tetracycline as co‐reducing and stabilizing agent, is reported, showing high water stability.
Abstract: A new synthetic methodology of water-soluble gold and silver nanoparticles (AuNPs@TC and AgNPs@TC), using the antibiotic tetracycline (TC) as co-reducing and stabilizing agent, is reported. Both colloids exhibit high water stability. The average sizes obtained were 25±10 and 15±5 nm, respectively. Both composites were tested against TC-resistant bacteria, presenting an increasing antibacterial effect in the case of AgNPs@TC. The sensing towards metal ions was also explored. An interesting and reversible affinity of AuNPs@TC towards AlIII cations in an aqueous system was also observed.
TL;DR: A dual catalytic IL effect is proposed for the mechanism of imidazole formation and a clear distinction between IL solvent effects on the reaction and IL catalysis is demonstrated.
Abstract: The mechanisms of a tetrasubstituted imidazole [2‐(2,4,5‐triphenyl‐1 H‐imidazol‐1‐yl)ethan‐1‐ol] synthesis from benzil, benzaldehyde, ammonium acetate, and ethanolamine in [Et2NH2][HSO4] ionic liquid (IL) are studied computationally. The effects of the presence of the cationic and anionic components of the IL on transition states and intermediate structures, acting as a solvent versus as a catalyst, are determined. In IL‐free medium, carbonyl hydroxylation when using a nucleophile (ammonia) proceeds with a Gibbs free energy (ΔG ≠) barrier of 49.4 kcal mol−1. Cationic and anionic hydrogen‐bond solute–solvent interactions with the IL decrease the barrier to 35.8 kcal mol−1. [Et2NH2][HSO4] incorporation in the reaction changes the nature of the transition states and decreases the energy barriers dramatically, creating a catalytic effect. For example, carbonyl hydroxylation proceeds via two transition states, first proton donation to the carbonyl (ΔG ≠=9.2 kcal mol−1) from [Et2NH2]+, and then deprotonation of ammonia (ΔG ≠=14.3) via Et2NH. Likewise, incorporation of the anion component [HSO4]− of the IL gives comparable activation energies along the same reaction route and the lowest transition state for the product formation step. We propose a dual catalytic IL effect for the mechanism of imidazole formation. The computations demonstrate a clear distinction between IL solvent effects on the reaction and IL catalysis.
TL;DR: Interestingly in the series of purine analogues, the 5′O, N‐bis‐tritylated fludarabine derivative revealed strong inhibitory activity against DENV at μm concentrations, however significantly weaker potency against YFV.
Abstract: A series of tritylated and dimethoxytritylated analogues of selected pyrimidine and purine nucleosides were synthesized and evaluated for their in vitro inhibitory activity against two important members of the genus Flavivirus in the Flaviviridae family, the yellow fever (YFV) and dengue viruses (DENV). Among all compounds tested, the 5′-O-tritylated and the 5′-O-dimethoxytritylated 5-fluorouridine derivatives exerted potency against YFV. Interestingly in the series of purine analogues, the 5′O, N-bis-tritylated fludarabine derivative revealed strong inhibitory activity against DENV at μm concentrations, however significantly weaker potency against YFV.
TL;DR: Electrochemical methodology can be employed to synthesize a variety of metal–salen/salan complexes which comprise diverse metal–ligand combinations and oxidation states, and tuning electrochemical potential, selective metalation of a Mn/Ni alloy is presented.
Abstract: Synthetic methods to prepare organometallic and coordination compounds such as Schiff-base complexes are diverse, with the route chosen being dependent upon many factors such as metal–ligand combination and metal oxidation state. In this work we have shown that electrochemical methodology can be employed to synthesize a variety of metal–salen/salan complexes which comprise diverse metal–ligand combinations and oxidation states. Broad application has been demonstrated through the preparation of 34 complexes under mild and ambient conditions. Unprecedented control over metal oxidation state (MII/III/IV where M=Fe, Mn) is presented by simple modification of reaction conditions. Along this route, a general protocol-switch is described which allows access to analytically pure FeII/III–salen complexes. Tuning electrochemical potential, selective metalation of a Mn/Ni alloy is also presented which exclusively delivers MnII/IV–salen complexes in high yield.
TL;DR: A DNA‐based epigenetic ON switch termed SAHA‐L is identified as the first‐ever multi‐target small molecule capable of inducing transcription programs associated with the human neural system and brain synapses networks in BJ human foreskin fibroblasts and 201B7‐iPS cells.
Abstract: An integrated multi-target small molecule capable of altering dynamic epigenetic and transcription programs associated with the brain and nervous system has versatile applications in the regulation of therapeutic and cell-fate genes. Recently, we have been constructing targeted epigenetic ON switches by integrating sequence-specific DNA binding pyrrole-imidazole polyamides with a potent histone deacetylase inhibitor SAHA. Here, we identified a DNA-based epigenetic ON switch termed SAHA-L as the first-ever multi-target small molecule capable of inducing transcription programs associated with the human neural system and brain synapses networks in BJ human foreskin fibroblasts and 201B7-iPS cells. Ingenuity pathway analysis showed that SAHA-L activates the signaling of synaptic receptors like glutamate and γ-aminobutyric acid, which are key components of autism spectrum disorders. The long-term incubation of SAHA-L in 201B7-iPS cells induced morphology changes and promoted a neural progenitor state. Our finding suggests that the tunable SAHA-L could be advanced as a cell-type-independent multi-target small molecule for therapeutic and/or cell-fate gene modulation.
TL;DR: The successful one‐pot total synthesis of rhamnolipids, a class of biosurfactants with 12 stereocenters, from butane as sole carbon and energy source through the design of a tailored whole‐cell biocatalyst is reported.
Abstract: Microbially derived surfactants, so-called biosurfactants, have drawn much attention in recent years and are expected to replace current petrochemical surfactants, owing to their environmental and toxicological benefits. One strategy to support that goal is to reduce production costs by replacing relatively expensive sugars with cheaper raw materials, such as short-chain alkanes. Herein, we report the successful one-pot total synthesis of rhamnolipids, a class of biosurfactants with 12 stereocenters, from butane as sole carbon and energy source through the design of a tailored whole-cell biocatalyst.
TL;DR: The effects of the click post‐functionalization on the properties of the porphyrin dyes were studied, and these functionalized porphyrs represent an interesting set of candidates for optoelectronic device components.
Abstract: Recently, third-order nonlinear properties of porphyrins and porphyrin polymers and coordination compounds have been extensively studied in relation to their use in photomedicine and molecular photonics. A new functionalized porphyrin dye containing electron-rich alkynes was synthesized and further modified by formal [2+2] click reactions with click reagents tetracyanoethylene (TCNE) and 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ). The photophysical properties of these porphyrin dyes, as well as the click reaction, were studied by UV/Vis spectroscopy. In particular, third-order nonlinear optical properties of the dyes, which showed typical d-π-A structures, were characterized by Z-scan techniques. In addition, the self-assembly properties were investigated through the phase-exchange method, and highly organized morphologies were observed by scanning electron microscopy (SEM). The effects of the click post-functionalization on the properties of the porphyrins were studied, and these functionalized porphyrin dyes represent an interesting set of candidates for optoelectronic device components.
TL;DR: The binary oxyhydroxy silicate colloids of AnIV could be potentially more mobile as a waterborne species than the well‐known mono‐component oxyhydroxide colloids.
Abstract: At the near-neutral and reducing aquatic conditions expected in undisturbed ore deposits or in closed nuclear waste repositories, the actinides Th, U, Np, and Pu are primarily tetravalent. These tetravalent actinides (AnIV) are sparingly soluble in aquatic systems and, hence, are often assumed to be immobile. However, AnIV could become mobile if they occur as colloids. This review focuses on a new type of AnIV colloids, oxyhydroxy silicate colloids. We herein discuss the chemical characteristics of these colloids and the potential implication for their environmental behavior. The binary oxyhydroxy silicate colloids of AnIV could be potentially more mobile as a waterborne species than the well-known mono-component oxyhydroxide colloids.
TL;DR: This represents the first successful radiolabeling of a non‐peptide angiotensin II receptor subtype 2 agonist, C21, currently in clinical trials for the treatment of idiopathic pulmonary fibrosis.
Abstract: We describe the development of a new methodology focusing on 11C-labeling of sulfonyl carbamates in a multicomponent reaction comprised of a sulfonyl azide, an alkyl alcohol, and [11C]CO. A number of 11C-labeled sulfonyl carbamates were synthesized and isolated, and the developed methodology was then applied in the preparation of a biologically active molecule. The target compound was obtained in 24±10 % isolated radiochemical yield and was evaluated for binding properties in a tumor cell assay; in vivo biodistribution and imaging studies were also performed. This represents the first successful radiolabeling of a non-peptide angiotensin II receptor subtype 2 agonist, C21, currently in clinical trials for the treatment of idiopathic pulmonary fibrosis.
TL;DR: A polymerizable LC phase was obtained from mixtures of TBIB with a methacrylate‐bearing fatty acid, providing an approach for the fabrication of nanoporous polymer films if the methacrysulfonic groups are polymerized.
Abstract: We report the formation of easily accessible hydrogen-bonded columnar discotic liquid crystals (LCs) based on tris-benzoimidazolyl benzene (TBIB) and commercially available fatty acids. By increasing the length of the fatty acid, the temperature range of liquid crystallinity was tuned. Introducing double bonds in octadecanoic acid lowered the crystallization temperature and increased the temperature range of the mesophase. Surprisingly, dimerized linoleic acid also forms an LC phase. When using branched aliphatic acids with the branching point close to the acid moiety, the mesophase was lost, whereas phosphonic acid or benzenesulfonic acid derivatives did have a mesophase, showing that the generality of this approach extends beyond carboxylic acids as the hydrogen-bond donor. Furthermore, a polymerizable LC phase was obtained from mixtures of TBIB with a methacrylate-bearing fatty acid, providing an approach for the fabrication of nanoporous polymer films if the methacrylate groups are polymerized. Finally, the higher solubility of methyl-TBIB was used to suppress phase separation in stoichiometric mixtures of the template molecule with fatty acids.
TL;DR: A new synthetic pathway to construct biphenols and diaryl selenides by the use of selenium dioxide is developed, which could act as pincer‐like ligands with further applications in organic synthesis or as ligands in transition metal catalysis.
Abstract: Biphenols are important structure motifs for ligand systems in organic catalysis and are therefore included in the category of so-called "privileged ligands". We have developed a new synthetic pathway to construct these structures by the use of selenium dioxide, a stable, powerful, and commercially available oxidizer. Our new, and easy to perform protocol gives rise to biphenols and diaryl selenides depending on the solvent employed. Oxidative treatment of phenols in acetic acid yields the corresponding biphenols, whereas conversion in pyridine results in the preferred formation of diaryl selenides. As a consequence, we were able to isolate a broad scope of novel diaryl selenides, which could act as pincer-like ligands with further applications in organic synthesis or as ligands in transition metal catalysis.