Nitrogen Heterocycle Synthesis through Hydride Abstraction of Acyclic Carbamates and Related Species: Scope, Mechanism, Stereoselectivity, and Product Conformation Studies.

Acyliminium ions and related species are potent electrophiles that can be quite valuable in the synthesis of nitrogen-containing molecules. This manuscript describes a protocol to form these intermediates through hydride abstractions of easily accessible allylic carbamates, amides, and sulfonamides that avoids the reversibility that is possible in classical condensation-based routes. These intermediates are used in the preparation of a range of nitrogen-containing heterocycles, and in many cases high levels of stereocontrol are observed.

Recent advances in NMR spectroscopy of ionic liquids.

This review presents recent developments in the application of NMR spectroscopic techniques in the study of ionic liquids. NMR has been the primary tool not only for the structural characterization of ionic liquids, but also for the study of dynamics. The presence of a host of NMR active nuclei in ionic liquids permits widespread use of multinuclear NMR experiments.

Hydrogen-bond directionality and symmetry in [C(O)NH](N)P(O)-based structures: a comparison between X-ray crystallography data and neutron-normalized values, and evaluation of reliability.

For [C(O)NH](N)P(O)-based structures, the magnitude of the differences in the N-H...

Conformational flexibility in amidophosphoesters: a CSD analysis completed with two new crystal structures of (CHO)P(O)X [X = NHCH and N(CHCH)].

The crystal structures of diphenyl (cycloheptylamido)phosphate, CHNOP or (CHO)P(O)(NHCH), (I), and diphenyl (dibenzylamido)phosphate, CHNOP or (CHO)P(O)[N(CHCH)], (II), are reported. The NHCH group in (I) provides two significant hydrogen-donor sites in N-H..

Synthesis and characterization of CaSr-Metal Organic Frameworks for biodegradable orthopedic applications.

Metal-organic frameworks (MOFs) formed from metals and organic ligands, are crystalline materials that are degradable in aqueous medium, and capable of releasing Ca and Sr ions. In this manuscript, the ability of MOFs to degrade and release osteogenic Ca and Sr ions was investigated. MOFs were generated by choosing osteoinductive Ca and Sr metals, and an organic ligand 1,3,5 tricarboxylicbenzene (H3BTC) as a linker.

Two single-enantiomer amidophosphoesters: a database study on the chirality of (O)P(O)(N)-based structures.

The crystal structures of two single-enantiomer amidophosphoesters with an (O)P(O)(N) skeleton, i.e. diphenyl [(R)-(+)-α-methylbenzylamido]phosphate, (I), and diphenyl [(S)-(-)-α-methylbenzylamido]phosphate, (II), both CHNOP, are reported.

Crystal structure and Hirshfeld surface analysis of (4)-1-butyl-4-(2-oxo-propyl-idene)-2,3,4,5-tetra-hydro-1-1,5-benzodiazepin-2-one.

The asymmetric unit of the title compound, CHNO, consists of two independent mol-ecules differing slightly in the conformations of the seven-membered rings and the butyl substituents, where the benzene rings are oriented at a dihedral angle of 34.56 (3)°. In the crystal, pairwise inter-molecular C-H⋯O and complementary intra-molecular C-H⋯O hydrogen bonds form twisted strips extending parallel to (012).

Chiral one-dimensional hydrogen-bonded architectures constructed from single-enantiomer phosphoric triamides.

The two single-enantiomer phosphoric triamides N-(2,6-difluorobenzoyl)-N',N''-bis[(S)-(-)-α-methylbenzyl]phosphoric triamide, [2,6-F-CHC(O)NH][(S)-(-)-(CH)CH(CH)NH]P(O), denoted L-1, and N-(2,6-difluorobenzoyl)-N',N''-bis[(R)-(+)-α-methylbenzyl]phosphoric triamide, [2,6-F-CHC(O)NH][(R)-(+)-(CH)CH(CH)NH]P(O), denoted D-1, both CHFNOP, have been investigated. In their structures, chiral one-dimensional hydrogen-bonded architectures are formed along [100], mediated by relatively strong N-H..

A review of NMR methods used in the study of the structure and dynamics of ionic liquids.

Recently, NMR spectroscopy has been emerging out as a powerful tool to study the structure and dynamics of ionic liquids (ILs) and ILs-Li salt mixtures. This mini-review primarily focuses on the applications of various NMR spectroscopic techniques such as self-diffusion measurements, NMR relaxometry, two-dimensional NMR, and other novel NMR approaches to study the structure and dynamics of ILs and its mixtures with lithium salts. Copyright © 2017 John Wiley & Sons, Ltd.

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts.

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.

Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature.

The well-established poor electrochemical cycling performance of the LiMn2O4 (LMO) spinel cathode material for lithium-ion batteries at elevated temperature stems from the instability of the Mn(3+) concentration. In this work, a microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e.

Understanding the mechanism of CO2 capture by 1,3 di-substituted imidazolium acetate based ionic liquids.

Efficient CO2 capture by ionic liquids needs a thorough understanding of underlying mechanisms of the CO2 interaction with ionic liquids, especially when it involves chemisorption. In this work we have systematically investigated the mechanism of CO2 capture by 1,3 di-substituted imidazolium acetate ionic liquids using density functional theory. Solvent effects are analyzed using QM/MM and QM/QM approaches with the help of molecular dynamics simulations and ONIOM methods.

Dynamic Behavior of N-Heterocyclic Carbene Boranes: Boron-Carbene Bonds in B,B-Disubstituted N,N-Dimethylimidazol-2-ylidene Boranes Have Substantial Rotation Barriers.

Dynamic NMR spectroscopy has been used to measure rotation barriers in five B,B-disubstituted 1,3-dimethylimidazol-2-ylidene boranes. The barriers are attributed to the sp(2)-sp(3) bond between C(1) of the N-heterocyclic carbene ring and the boron atom. Bonds to boron atoms bearing a thexyl (1,1,2-trimethylpropyl) group show especially high barriers, ranging from 75-86 kJ mol(-1).

Molecular simulation and experimental study of CO2 absorption in ionic liquid reverse micelle.

The structure and dynamics for CO2 absorption in ionic liquid reverse micelle (ILRM) were studied using molecular simulations. The ILRM consisted of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) ionic liquid (IL) as the micelle core, the benzylhexadecyldimethylammonium ([BHD](+)) chloride ([Cl](-)) was the cationic surfactant, and benzene was used as the continuous solvent phase in this study. The diffusivity values of this ILRM system were also experimentally determined.

Toward a Materials Genome Approach for ionic liquids: synthesis guided by ab initio property maps.

The Materials Genome Approach (MGA) aims to accelerate development of new materials by incorporating computational and data-driven approaches to reduce the cost of identification of optimal structures for a given application. Here, we use the MGA to guide the synthesis of triazolium-based ionic liquids (ILs). Our approach involves an IL property-mapping tool, which merges combinatorial structure enumeration, descriptor-based structure representation and sampling, and property prediction using molecular simulations.

High-resolution slice selection NMR for the measurement of CO2 diffusion under non-equilibrium conditions.

We present a simple and an efficient approach using spatially selective NMR to investigate solvation and diffusion of CO2 in ionic liquids. The techniques demonstrated here are shown as novel and effective means of studying solvated gas dynamics under non-equilibrium conditions without the need for conventional high power gradients.

Diglycerol-based polyesters: melt polymerization with hydrophobic anhydrides.

The melt polymerization of diglycerol with bicyclic anhydride monomers derived from a naturally occurring monoterpene provides an avenue for polyesters with a high degree of sustainability. The hydrophobic anhydrides are synthesized at ambient temperature via a solvent-free Diels-Alder reaction of α-phellandrene with maleic anhydride. Subsequent melt polymerizations with tetra-functional diglycerol are effective under a range of [diglycerol]/[anhydride] ratios.

Sodium dodecyl sulfate monomers induce XAO peptide polyproline II to α-helix transition.

XAO peptide (Ac-X2A7O2-NH2; X: diaminobutyric acid side chain, -CH2CH2NH3(+); O: ornithine side chain, -CH2CH2CH2NH3(+)) in aqueous solution shows a predominantly polyproline II (PPII) conformation without any detectable α-helix-like conformations. Here we demonstrate by using circular dichroism (CD), ultraviolet resonance Raman (UVRR) and nuclear magnetic resonance (NMR) spectroscopy that sodium dodecyl sulfate (SDS) monomers bind to XAO and induce formation of α-helix-like conformations. The stoichiometry and the association constants of SDS and XAO were determined from the XAO-SDS diffusion coefficients measured by pulsed field gradient NMR.

Systematic comparison of sets of (13)C NMR spectra that are potentially identical. Confirmation of the configuration of a cuticular hydrocarbon from the cane beetle Antitrogus parvulus.

A systematic process is introduced to compare (13)C NMR spectra of two (or more) candidate samples of known structure to a natural product sample of unknown structure. The process is designed for the case where the spectra involved can reasonably be expected to be very similar, perhaps even identical. It is first validated by using published (13)C NMR data sets for the natural product 4,6,8,10,16,18-hexamethyldocosane.

Identification, mechanism of action, and antitumor activity of a small molecule inhibitor of hippo, TGF-β, and Wnt signaling pathways.

Embryonic signaling pathways, in particular those mediated by Wnt and TGF-β, are known to play key roles in tumor progression through the induction of epithelial-mesenchymal transition (EMT). Their simultaneous targeting could therefore represent a desirable anticancer strategy. On the basis of recent findings that both Wnt and TGF-β-associated pathways are regulated by Hippo signaling in mammalian cells, we reasoned that targeting the latter would be more effective in inhibiting EMT.