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An expansion of methodologies aimed at the formation of versatile organonitriles, via the intramolecular aminocyanation of unactivated alkenes, is herein reported. Importantly, the need for a rigid tether in these reactions has been obviated. The ease-of-synthesis and viability of substrates bearing flexible backbones has permitted for diastereoselective variants as well. We demonstrated the utility of this methodology with the formation of pyrrolidones, piperidinones, isoindolinones, and sultams. Furthermore, subsequent transformation of these motifs into medicinally relevant molecules is also demonstrated. A double crossover 13C-labeling experiment is consistent with a fully intramolecular cyclization mechanism. Deuterium labeling experiments support a mechanism involving syn-addition across the alkene.

Binding of antigen to IgE-high affinity FcεRI complexes on mast cells and basophils results in the release of preformed mediators such as histamine and de novo synthesis of cytokines causing allergic reactions. Src-like adapter protein (SLAP) functions co-operatively with c-Cbl to negatively regulate signaling downstream of the T cell receptor, B cell receptor, and receptor tyrosine kinases (RTK). Here, we investigated the role of SLAP in FcεRI-mediated mast cell signaling, using bone marrow derived mast cells (BMMCs) from SLAP knock out (SLAP KO) mice. Mature SLAP-KO BMMCs displayed significantly enhanced antigen induced degranulation and synthesis of IL-6, TNFα, and MCP-1 compared to wild type (WT) BMMCs. In addition, SLAP KO mice displayed an enhanced passive cutaneous anaphylaxis response. In agreement with a negative regulatory role, SLAP KO BMMCs showed enhanced FcεRI-mediated signaling to downstream effector kinases, Syk, Erk, and Akt. Recombinant GST-SLAP protein binds to the FcεRIβ chain and to the Cbl-b in mast cell lysates, suggesting a role in FcεRI down regulation. In addition, the ubiquitination of FcεRIγ chain and antigen mediated down regulation of FcεRI is impaired in SLAP KO BMMCs compared to the wild type. In line with these findings, stimulation of peripheral blood human basophils with FcεRIα antibody, or a clinically relevant allergen, resulted in increased SLAP expression. Together, these results indicate that SLAP is a dynamic regulator of IgE-FcεRI signaling, limiting allergic responses.

The cyclization of an alkene-bearing cyclopentanone to a [2.2.1]-norcamphor ring system is described. The reaction is catalyzed by a combination of rhodium and Bronsted acid. Control experiments indicate that both are needed for acceptable yield. Control experiments with bulky base additives show that rhodium promotes alkene isomerization, likely the first step of this cascade reaction, and that rhodium alone does not promote cyclization. Cyclization is promoted by Bronsted acid in a Prins-type cyclization and carbocation rearrangement process. Trace Bronsted acid present in commercial samples of Rh(cod)2OTf is likely responsible for the observed reaction. Indeed, the norcamphor product can be obtained simply with strong acid, presumably initiated by acid-promoted alkene isomerization. Since our initial motivation for this work was the development of rhodium catalysts for the activation of C–C bonds adjacent to ketones, this communication serves to identify other, perhaps less obvious, pathways for the reactions of unsaturated ketone compounds by the action of rhodium catalysts.

The electronic energy transfer (EET) usually induces the fluorescence self-quenching, but it has been positively used here to tune and/or switch the photoluminescence (PL) of ZnO nanoparticles (NPs). Monodisperse ZnO nanospheres, rods, tripods, and clusters with tunable sizes have been synthesized to reproducibly and finely control the NP aggregation because EET is sensitive to the interparticle separation. The complex reactions between these NPs and their dispersion media have been used to further control the EET for tuning the ZnO PL. By changing the NP concentrations, shapes, and/or the cluster sizes, the band-edge UV PL of the ZnO NPs dispersed in alcohol or water is modified in both intensity and peak position, and new blue emissions with tunable intensity around 418, 435, and 468 nm are induced. As confirmed by the X-ray diffraction patterns and the infrared, PL, absorption, and Raman spectra, the ZnO NPs made here can slowly react with ethanol to form a new composite ZnO–(C2H5OH)n, which changes th...

Tuning the bandgap and cytotoxicity of ZnO nanoparticles (NPs) is very important, not only for customizing their optoelectronic and biomedical applications, but also for their cytotoxicity assay and safe usage. A unique soft-template of polyvinylpyrrolidone has been developed here to realize a rapid room-temperature neutral synthesis of ZnO with controlled nanostructures for tuning the bandgap and cytotoxicity of ZnO. By simply changing the reagent stoichiometry and the soft-template shape, high-purity ZnO rods, tripods, tubes, and unique T-like tubes with tunable size, surface composition/charge, bandgap, and cytotoxicity are obtained. It has been revealed that the ZnO bandgap can be remarkably reduced by introducing the surface nonstoichiometry; and the ZnO-induced cytotoxicity can be tuned by the size, shape, surface charge/composition, and bandgap of ZnO NPs at different degrees. Significantly, both the photochemistry reaction and the reactive oxygen species induced by ZnO NPs are not necessary for the ZnO-induced cytotoxicity.

Alkene oxyacylation is a new strategy for the preparation of β-oxygenated ketones. Now, with Ir catalysis and low-cost salicylate esters, alkene oxyacylation can be promoted by simple and versatile hydroxyl directing groups. This paper discusses catalyst optimization, substituent effects, mechanistic experiments, and the challenges associated with asymmetric catalysis. Crossover experiments point to several key steps of the mechanism being reversible, including the most likely enantiodetermining steps. The oxyacylation products are also prone to racemization without catalyst when heated alone; however, crossover is not observed without catalyst. These observations account for the low levels of enantioinduction in alkene oxyacylation. The versatility of the hydroxyl directing group is highlighted by demonstrating further transformations of the products.

A metal-free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C6F5)3 activates N-sulfonyl cyanamides, thus leading to a formal cleavage of the N-CN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom-economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups. Labeling experiments with (13)C suggest a fully intramolecular cyclization pattern due to the lack of label scrambling in double crossover experiments. Catalysis with Lewis acid is realized and the reaction can be conducted under air.

A new coordination polymer of polyoxomolybdate, {[Cu(4)(bbp)(5)Mo(6)O(22)]·(H(2)O)(4)}(∞) (bbp = 1,4-bis(benzoimidazol-1-yl)phenyl), has been synthesized under solvothermal reaction, which represents a double-bridging interpenetrating α-Po network based on the bimetallic cluster {Cu(4)Mo(6)}. The thermogravimetric and electrochemical behaviors have also been studied.

Basic ion-exchange resins, one kind of polystyryl-supported tertiary amine, were demonstrated to be highly efficient and recyclable catalysts for the fixation of carbon dioxide with aziridines under mild conditions, leading to the formation of 5-aryl-2-oxazolidinone with excellent regio-selectivities. Notably, neither solvents nor any additives were required, and the catalyst could be recovered by simple filtration and directly reused at least five times without significant loss of catalytic activity and selectivity. The present protocol has been applied to reactions of epoxides/propargyl amines with CO2/CS2. This solvent-free process thus represents environmentally friendly catalytic conversion of CO2 into value-added chemicals and may have potential in various continuous flow reactors in industry.

Sparked by the strategy of pillared-layer MOFs, three formate coordination polymers, {[Ni(2)(HCO(2))(3)(L)(2)](NO(3)).2H(2)O}(infinity) (1), {[Co(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (2), and {[Cu(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (3), have been synthesized by employing the rodlike ligand 4,4'-bis(imidazol-1-yl)biphenyl (L) as the pillar. Structural analysis indicates that the title complexes 1-3 are isostructural compounds, which possess metal-formate 2D layers perpendicularly pillared by the ligand L to afford a 3D open framework. This is an interesting example of a Kagome lattice based on the formate mediator. Moreover, the formate anion of this 2D Kagome layer exhibits various bridging modes: anti-anti, syn-anti, and 3.21 modes. Their magnetic measurements reveals that only complex 1 presents the spin canting phenomenon, while its isostructural Co(II) and Cu(II) complexes are simply paramagnets with antiferromagnetic coupling.

Alkene oxyacylation is a new strategy for the preparation of β-oxygenated ketones. Now, with Ir catalysis and low-cost salicylate esters, alkene oxyacylation can be promoted by simple and versatile hydroxyl directing groups. This paper discusses catalyst optimization, substituent effects, mechanistic experiments, and the challenges associated with asymmetric catalysis. Crossover experiments point to several key steps of the mechanism being reversible, including the most likely enantiodetermining steps. The oxyacylation products are also prone to racemization without catalyst when heated alone; however, crossover is not observed without catalyst. These observations account for the low levels of enantioinduction in alkene oxyacylation. The versatility of the hydroxyl directing group is highlighted by demonstrating further transformations of the products.

The title reaction affords functionalized indanones (II) in moderate to high yields and tolerates substitution at various positions on the aromatic ring including electron donating and electron withdrawing groups.

Geminal substitution of the alkene is required for the reaction since the allyl substrate does not react.

Reported here is a palladium catalyzed intramolecular acylcyanation of alkenes using α-iminonitriles. Through this method, highly functionalized indanones are synthesized in moderate to high yields using Pd(PPh3)4, without need for any additional ligands, and a common Lewis acid (ZnCl2). Additionally, the reaction tolerates substitution at various positions on the aromatic ring including electron donating, and electron withdrawing groups.

We demonstrate experimentally that magnetism in ZnO, TiO2 ,C eO2 ,a nd SnO2 nanocrystals (NCs) has a fluctuant nature that varies with capping surfactant type and concentration. By developing a forced hydrolysis approach with additional postprocessing for the synthesis and surfactant capping of these NCs, we effectively avoid the influence of size, shape, and magnetic impurities on the magnetic behavior of NCs, thus revealing the systematic influence of the capping surfactants on the NC magnetism. The x-ray photoelectron spectroscopy results and theoretical calculations clearly show that the magnetism fluctuation with surfactant concentration can be attributed to the periodic variation of spins, which arises from the concentration-dependent electron transfer from surfactants to NCs. Our results not only explain the previously reported seemingly irregular magnetism induced by capping surfactants but also provide an effective approach to tune or optimize the NC magnetism.