Annulation Cascades of N-Allyl- N-((2-bromoaryl)ethynyl)amides Involving C-H Functionalization.

An annulation cascades of N-allyl- N-((2-bromoaryl)ethynyl)amides with terminal alkynes or 1,3-dicarbonyls involving C-H functionalization for producing 2,3-functionalized indoles has been first developed by means of Cu catalysis. The method is enabled by the formation of the ketenimine intermediates to deliver 2,3-disubstituted indoles through a sequence of aza-Claisen rearrangement, C-H functionalization, Ullmann C-N coupling, and cyclization.

A General Protocol for C-H Difluoromethylation of Carbon Acids with TMSCF Br.

An efficient method for the selective C-difluoromethylation of carbon acids with the reagent TMSCF Br has been developed. A variety of structurally diverse sp - and sp-hybridized carbon nucleophiles, including esters, amides, fluorenes, terminal alkynes, β-ketoesters, malonates, and other activated C-H nucleophiles, could be efficiently and selectively transformed into the corresponding C-difluoromethylated products under mild conditions. This protocol is also effective for the late-stage difluoromethylation of pharmaceutically relevant molecules and can be readily scaled up.

Rhodium-Catalyzed Annelation of Benzoic Acids with α,β-Unsaturated Ketones with Cleavage of C-H, CO-OH, and C-C Bonds.

In the presence of a [Cp*RhCl ] catalyst, the Lewis acid In(OTf) , and the mild base Na CO , aromatic carboxylates and α,β-unsaturated ketones undergo a unique hydroarylation/Claisen/retro-Claisen process to give the corresponding indanones. In this carboxylate-directed ortho-C-H annelation, the C-COR bond of the ketone and the CO-OH group of the aromatic carboxylate are cleaved, and the hydroxy group is transferred from the aromatic to the aliphatic acyl residue. This reactivity is synthetically useful, particularly when starting from cyclic ketones, which are converted into indanones bearing aliphatic carboxylate side chains, thus greatly increasing the molecular complexity of aromatic carboxylates in a single step.

Cobalt-Catalyzed N-O and C-C Bond Cleavage in 1,2-Oxazetidines: Solvent-Controlled C-H Aminomethylation and Hydroxymethylation of Heteroarenes.

An efficient cobalt-catalyzed ring-opening reaction of bench-stable 1,2-oxazetidines with heteroarenes was unprecedentedly developed. The sustainable Cp *Co(III) catalyst enables a distinctive merger of C-H activation with concomitant N-O and C-C cleavages of 1,2-oxazetidine, leading to site-selective C-H aminomethylation and hydroxymethylation of heteroaromatic compounds containing a broad range of functional groups. Preliminary control experiments unravel some essential mechanistic features of this one-pot transformation.

Divergent C-H Oxidative Radical Functionalization of Olefins to Install Tertiary Alkyl Motifs Enabled by Copper Catalysis.

An efficient tertiary alkylation reaction of olefins with 1,3-dicarbonyl compounds was developed by virtue of copper catalyst without the use of expensive ligands or additives. In contrast to alkyl Heck-type reaction, alkyl halide is not required. Notably, by varying the nitrogen and air atmosphere, the reaction selectively produces alkylation and alkylation-oxygenation products, respectively.

Impact of Initial Shunt Type on Echocardiographic Indices in Children After Single Right Ventricle Palliations.

Background Heart size and function in children with single right ventricle (RV) anomalies may be influenced by shunt type at the Norwood procedure. We sought to identify shunt-related differences during early childhood after staged surgical palliations using echocardiography. Methods We compared echocardiographic indices of RV, neoaortic, and tricuspid valve size and function at 14 months, pre-Fontan, and 6 years in 241 subjects randomized to a Norwood procedure using either the modified Blalock-Taussig shunt or RV-to-pulmonary-artery shunt.

Molecular mechanism comparison of decarbonylation with deoxygenation and hydrogenation of 5-hydroxymethylfurfural catalyzed by palladium acetate.

The selective removal of oxygen from 5-hydroxymethylfurfural (HMF) is challenging for the effective utilization of biomass. The catalytic mechanisms of palladium acetate toward the conversion of HMF to furfuryl alcohol (FFA), 5-methylfurfural (5-MF) and 2,5-dihydroxymethyl furan (DHMF) have been theoretically investigated. The decarbonylation of HMF to FFA includes (i) migratory extrusion, (ii) metal-acetate-co-assisted deprotonation, (iii) decarbonylation, (iv) metal-assisted deprotonation, and (v) migratory extrusion and catalyst regeneration.

Pd-Catalyzed Intramolecular Chemoselective C(sp2)-H and C(sp3)-H Activation of N-Alkyl- N-arylanthranilic Acids.

A controllable palladium-catalyzed intramolecular C-H activation of N-alkyl- N-arylanthranilic acids has been developed. The methodology allows selective synthesis of 1,2-dihydro-(4 H)-3,1-benzoxazin-4-ones and carbazoles from the same starting materials and palladium catalyst. The selectivity is controlled by the oxidant.

Dual Gold/Silver Catalysis Involving Alkynylgold(III) Intermediates Formed by Oxidative Addition and Silver-Catalyzed C-H Activation for the Direct Alkynylation of Cyclopropenes.

While gold-mediated synergistic catalytic processes involving transmetalations with other metals are well understood, Au /Au cycles in these reactions are rarely reported. Herein a gold-catalyzed direct alkynylation of cyclopropenes is enabled by two operating catalytic cycles, an oxidative catalytic cycle involving an alkynyl Au complex formed by oxidative addition and one involving a silver-mediated C-H activation.

Rapid Determination of Acid Value of Edible Oils via FTIR Spectroscopy Using Infrared Quartz Cuvette.

A Fourier transform infrared (FTIR) spectroscopy with infrared quartz cuvette (IQC) as spectral accessory method was developed to determine acid value (AV) of edible oils. The absorption peak at 5680 cm/5487 cm ascribed to the C-H stretching band was a substitute for the peak of an internal standard. Partial least square (PLS) regression was used for AV calibration, and samples were validated by titrated method.

Ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of benzylic alcohols with internal alkynes: entry to isocoumarins.

A new ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of primary benzylic alcohols with internal alkynes is described, which enables benzylic alcohols as weakly directing group precursors to access isocoumarins via multiple C-H functionalization. The reaction works well with a broad substrate scope, tolerates a wide range of functional groups, and incorporates practically the isocoumarin unit into diverse bioactive molecules. Mechanistic studies indicate that activation of aryl C(sp)-H bonds is achieved through the generation of the active benzoyloxy-Ru(ii) intermediates via oxidation of benzylic alcohols using an electrooxidative Ru(ii) catalyst.

High-Phosphate Diet Induces Exercise Intolerance and Impairs Fatty Acid Metabolism in Mice.

Background: Inorganic phosphate (Pi) is used extensively as a preservative and a flavor enhancer in the Western diet. Physical inactivity, a common feature of Western societies, is associated with increased cardiovascular morbidity and mortality. It is unknown whether dietary Pi excess contributes to exercise intolerance and physical inactivity.

Photocatalytic Hydrogen-Evolving Cross-Coupling of Arenes with Primary Amines.

Herein, we described a cooperative catalyst system consisting of an acridinium photoredox catalyst and a cobalt-based proton-reduction catalyst that is effective for the C-H amination of arenes with concomitant generation of hydrogen. This oxidant-free method allows a variety of amines with diverse functional groups to be converted to aromatic amines. Additionally, this protocol can also be extended to hydrolytically unstable benzophenone imines.

Perovskite-Polymer Blends Influencing Microstructures, Nonradiative Recombination Pathways, and Photovoltaic Performance of Perovskite Solar Cells.

Solar cells based on organic-inorganic halide perovskites are now leading the photovoltaic technologies because of their high power conversion efficiency. Recently, there have been debates on the microstructure-related defects in metal halide perovskites (grain size, grain boundaries, etc.) and a widespread view is that large grains are a prerequisite to suppress nonradiative recombination and improve photovoltaic performance, although opinions against it also exist.

Screening of novel histone deacetylase 7 inhibitors through molecular docking followed by a combination of molecular dynamics simulations and ligand-based approach.

Histone acetylation/deacetylation is a key mechanism for transcription regulation which plays an important role in control of gene expression, tissue growth, and development. In particular, histone deacetylase 7 (HDAC7), a member of class IIa HDACs, is crucial to maintain cell homeostasis, and HDAC7 has emerged as a new target for cancer therapy. In this study, molecular docking was applied to screen candidate inhibitors and 21 compounds were found.

Earthworms, Rice Straw, and Plant Interactions Change the Organic Connections in Soil and Promote the Decontamination of Cadmium in Soil.

The joint effects of earthworms and crop straw on toxic metal speciation are not clear, and very limited information is available regarding the effects of their interaction on Cd mobility in Cd contaminated soil or in remediation processes involving plants. This study evaluated their impacts on Cd mobile form changes in soil and their effects on Cd uptake by plants. Treatments included both planted and unplanted-Cd-contaminated soil with or without rice straw and/or earthworms.

Endothelial Mitochondrial Preprotein Translocase Tomm7-Rac1 Signaling Axis Dominates Cerebrovascular Network Homeostasis.

Objective- Mitochondria are the important yet most underutilized target for cardio-cerebrovascular function integrity and disorders. The Tom (translocases of outer membrane) complex are the critical determinant of mitochondrial homeostasis for making organs acclimate physiological and pathological insults; however, their roles in the vascular system remain unknown. Approach and Results- A combination of studies in the vascular-specific transgenic zebrafish and genetically engineered mice was conducted.

Catalytic Radical Process for Enantioselective Amination of C(sp )-H Bonds.

A new catalytic radical system involving Co -based metalloradical catalysis is effective in activating sulfamoyl azides for enantioselective radical 1,6-amination of C(sp )-H bonds, affording six-membered chiral heterocyclic sulfamides in high yields with excellent enantioselectivities. The Co -catalyzed C-H amination features an unusual degree of functional-group tolerance and chemoselectivity. The unique reactivity and stereoselectivity is attributed to the underlying stepwise radical pathway.

Oxidative three-component 1,2-alkylarylation of alkenes with alkyl nitriles and N-heteroarenes.

An indium-promoted intermolecular oxidative 1,2-alkylarylation of alkenes with alkyl nitriles and N-heteroarenes enabled by C(sp3)-H/C(sp2)-H functionalization is presented. This oxidative radical strategy allows the formation of two new C-C bonds through transformations of two different C-H bonds across the alkenes in a controlled single-step manner, and offers a general, highly atom-economic route for the production of new functionalized N-heteroarenes, including indoles, pyrrolo[2,3-b]pyridine, pyrrolo[3,2,1-ij]quinolone and pyrroles.

Theoretical studies on the mechanism of Pd-catalyzed regioselective C-H acylation of azoxybenzenes with α-oxocarboxylic acids.

The reaction mechanism of the Pd2+-catalyzed regioselective C(sp2)-H acylation of azoxybenzenes with α-oxocarboxylic acids has been studied by density functional theory (DFT) calculations. This reaction mechanism involves five major steps: C-H activation, deprotonation, decarboxylation, reductive elimination and oxidation. Our calculation results indicate that the N-coordinated pathway is better than the O-coordinated pathway, which can be interpreted by distortion-interaction analysis of the C-H bond activation transition states.

Dearomative Dienolate-Mediated Catalysis: A Remote Activation Strategy for Asymmetric Functionalization of Benzylic C-H Bonds of Heteroaryl Aldehydes.

A dearomative remote activation strategy for the asymmetric functionalization of benzylic C-H bonds of heteroaryl aldehydes under bifunctional Brønsted base catalysis has been developed. The in situ generated o-QDMs-type dienolate intermediates were efficiently and stereoselectively trapped by nitroolefins through an asymmetric Michael/nitro-aldol cascade reaction. Using this strategy, a wide variety of synthetically significant tetrahydrodibenzothiophene and tetrahydrodibenzofuran derivatives were synthesized in good yields with high enantioselectivities.

Boron(III)-Catalyzed C2-Selective C-H Borylation of Heteroarenes.

A BF ⋅Et O-catalyzed C2-selective C-H borylation of indoles with bis(pinacolato)diboron was developed to afford indole-2-boronic acid pinacol esters. A variety of functional groups were tolerated, and other heteroarenes like pyrrole and benzo[b]thiophene were also suitable substrates. An electrophilic substitution mechanism was proposed based on the preliminary mechanistic studies.

A reusable cyanide sensor via activation of C-H group: trifluoromethylcarbinol-directed meta-C-H cyanomethylation of naphthalimide.

A fluorescent and colorimetric anion sensor based on the activated C-H group has been developed, and its reusability and ability to selectively detect cyanides have been demonstrated. The system utilizes trifluoromethylcarbinol-directed C-H regioselective cyanomethylation for direct C-C bond formation between the fluorophore and acetonitrile. The present paper also describes a novel strategy for the enhancement of carbanion stability by a potential intramolecular C[double bond, length as m-dash]OH-C hydrogen bonding system, thus providing a new way to develop activated CH-based anion receptors.

Molecular Coupling between Organic Molecules and Metal.

Molecular couplings at interfaces play important roles in determining the performance of nanophotonics and molecular electronics. In this Letter, using femtosecond sum frequency generation to trace free-induction decay of vibrationally excited aromatic thiol molecules immobilized on metal with and without the bridged methylene group(s), metal surface free electron-coupled and uncoupled phenyl C-H stretching vibrational modes were identified, with dephasing times of ∼0.28 and ∼0.