Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Iodocyclization in Aqueous Media and Supramolecular Reaction Control Using Water-Soluble Hosts.

ABSTRACT: Iodocyclization of 2-alkynylanisoles is an efficient route for synthesizing substituted benzofurans. Reaction efficiency with copper(II) sulfate and sodium iodide in an aqueous slurry under mild conditions is a manifold higher than in organic solvents. Water-soluble hosts of the cyclodextrin family solubilize the compounds in aqueous media and affect the reaction efficiency through conformation control and steric interactions. Computational chemistry and spectral titration provide information on the host-guest complex structure and insight into the mechanistic basis of the observed effects.

SUBMITTER: Bokoskie T

PROVIDER: S-EPMC6822118 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Iodocyclization in Aqueous Media and Supramolecular Reaction Control Using Water-Soluble Hosts.

Bokoskie Treyvon T Cunningham Christopher C Kornman Cory C Kesharwani Tanay T Pattabiraman Mahesh M

ACS omega 20191017 18

Iodocyclization of 2-alkynylanisoles is an efficient route for synthesizing substituted benzofurans. Reaction efficiency with copper(II) sulfate and sodium iodide in an aqueous slurry under mild conditions is a manifold higher than in organic solvents. Water-soluble hosts of the cyclodextrin family solubilize the compounds in aqueous media and affect the reaction efficiency through conformation control and steric interactions. Computational chemistry and spectral titration provide information on ...[more]

PMID: 31681890

Similar Datasets

Molecular Recognition in an Aqueous Medium Using Water-Soluble Prismarene Hosts.

Project description:The synthesis of water-soluble prism[n]arenes (n = 5 and 6) bearing anionic carboxylato groups on the rims is described. The binding properties of this novel class of water-soluble hosts are studied by nuclear magnetic resonance and calorimetry. The complexation of singly and doubly charged ammonium guests with the more rigid pentamer is enthalpically driven by secondary interactions, while the thermodynamic fingerprint for the larger hexamer reveals driving forces that strongly depend on the guest charge and/or size.

| S-EPMC9016763 | biostudies-literature

Thermodynamics of Supramolecular Associations with Macrocyclic Water-Soluble Hosts.

Project description:The thermodynamic study of the complexation of the β-cyclodextrins and p-sulfonatocalix[n]arenes (CnS) with the 4-aminoazobenzene was reported and was carried out by molecular dynamics simulations. We determined the whole thermodynamic properties (K, Δr G°, Δr H°, and TΔr S°) using the potential of mean force (PMF) technique and more precisely the adaptive biasing force method. Depending on both the nature of the host molecule and the pH of the solution, the PMF profiles present different shapes and energy minima. Considering the complexity of these PMF profiles, we are also interested in the structural properties of these associations. Hence, we calculated hydrogen bonds, Lennard-Jones and electrostatic energies, the number of atoms of the guest molecule inserted inside the cagelike host molecule, and the number of water molecules expelled from the cavity.

| S-EPMC6796899 | biostudies-literature

A new β-cyclodextrin-based nickel as green and water-soluble supramolecular catalysts for aqueous Suzuki reaction.

Project description:A water-soluble nickel complex based on amino-β-CD was developed using a facile method and exhibits excellent catalytic performance in the Suzuki reaction in water. This synthesized complex has been characterized using UV-Vis, AAS, TGA, and FT-IR techniques. The easily synthesized novel supramolecular catalysts have been applied as a green and eco-friendly catalyst in the Suzuki coupling for preparing diverse biaryls. This result indicates that using 2.5 mol% of nickel, K2CO3 as the best base, and water as the green solvent are the best reaction conditions. This new catalyst features easy handling, low-cost, mild, and simple protocol. The use of low-cost and accessibility of the reagents, modest conditions, and good yields of products are notable characteristics of this method. Using aqueous media with this catalyst as a proper catalyst makes the presented process a fascinating method compared to most reports. Under mild reaction conditions, this green Ni(II)-β-CD catalyst displayed recyclable behavior seven times with minor loss in its catalytic activity.

| S-EPMC10693598 | biostudies-literature

Synthesis of water-soluble surfactants using catalysed condensation polymerisation in green reaction media.

Project description:Sustainable and biobased surfactants are required for a wide range of everyday applications. Key drivers are cost, activity and efficiency of production. Polycondensation is an excellent route to build surfactant chains from bio-sourced monomers, but this typically requires high processing temperatures (≥200 °C) to remove the condensate and to lower viscosity of the polymer melt. In addition, high temperatures also increase the degree of branching and cause discolouration through the degradation of sensitive co-initiators and monomers. Here we report the synthesis of novel surface-active polymers from temperature sensitive renewable building blocks such as dicarboxylic acids, polyols (d-sorbitol) and fatty acids. We demonstrate that the products have the potential to be key components in renewable surfactant design, but only if the syntheses are optimised to ensure linear chains with hydrophilic character. The choice of catalyst is key to this control and we have assessed three different approaches. Additionally, we also demonstrate that use of supercritical carbon dioxide (scCO2) can dramatically improve conversion by reducing reaction viscosity, lowering reaction temperature, and driving condensate removal. We also evaluate the performance of the new biobased surfactants, focussing upon surface tension, and critical micelle concentration.

| S-EPMC8145305 | biostudies-literature

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions.

Project description:Since several years the inclusion of organic compounds (guests) within the hydrophobic cavity (host) of cyclodextrins (CDs) has been the subject of many investigations. Interestingly, the formation of inclusion complexes could affect the properties of the guest molecules and, for example, the influence of the delivery system can be a method to improve/change the photochemical behavior of the guest. In particular, very recent studies have shown the protective role of CDs preventing the degradation of the encapsulated guest. Starting from this consideration, in this work, only the structure and complexation mode of the inclusion complexes involving 4-thiothymidine (S(4)TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB CD) were investigated by different spectroscopic techniques (UV-vis, FTIR-ATR, (1)H NMR) and cyclic voltammetry analysis (CV). This work is necessary for a prospective research on the photoreactivity of S(4)TdR in aqueous environment and in the presence of CDs to prevent its degradation under irradiation. UV-vis, FTIR-ATR and CV measurements suggested the formation of supramolecular structures involving the employed CDs and mainly the pyrimidine ring of S(4)TdR. (1)H NMR analyses confirmed such indication, unveiling the presence of inclusion complexes. The strongest and deepest interactions were suggested when TRIMEB and DIMEB CDs were studied. The S(4)TdR affinity towards CDs was also evaluated by using the Benesi-Hildebrand (B-H) equation at 25 °C employing CV and (1)H NMR methods. The stoichiometry of the interaction was also inferred and it appears to be 1:1 for all examined CDs.

| S-EPMC4901997 | biostudies-literature

Pathway and Length Control of Supramolecular Polymers in Aqueous Media via a Hydrogen Bonding Lock.

Project description:Programming the organization of ?-conjugated systems into nanostructures of defined dimensions is a requirement for the preparation of functional materials. Herein, we have achieved high-precision control over the self-assembly pathways and fiber length of an amphiphilic BODIPY dye in aqueous media by exploiting a programmable hydrogen bonding lock. The presence of a (2-hydroxyethyl)amide group in the target BODIPY enables different types of intra- vs. intermolecular hydrogen bonding, leading to a competition between kinetically controlled discoidal H-type aggregates and thermodynamically controlled 1D J-type fibers in water. The high stability of the kinetic state, which is dominated by the hydrophobic effect, is reflected in the slow transformation to the thermodynamic product (several weeks at room temperature). However, this lag time can be suppressed by the addition of seeds from the thermodynamic species, enabling us to obtain supramolecular polymers of tuneable length in water for multiple cycles.

| S-EPMC7898687 | biostudies-literature

Unveiling Polymerization Mechanism in pH-regulated Supramolecular Fibers in Aqueous Media.

Project description:An amine functionalized C3 -symmetric benzotrithiophene (BTT) monomer has been designed and synthetized in order to form pH responsive one-dimensional supramolecular polymers in aqueous media. While most of the reported studies looked at the effect of pH on the size of the aggregates, herein, a detailed mechanistic study is reported, carried out upon modifying the pH to trigger the formation of positively charged ammonium groups. A dramatic and reversible change in the polymerization mechanism and size of the supramolecular fibers is observed and ascribed to the combination of Coulombic repulsive forces and higher monomer solubility. Furthermore, the induced frustrated growth of the fibers is further employed to finely control the one-dimensional supramolecular polymerisation and copolymerization processes.

| S-EPMC8456867 | biostudies-literature

Reaction of 1-propanol with Ozone in Aqueous Media.

Project description:The main aim of this work is to substantiate the mechanism of 1-propanol oxidation by ozone in aqueous solution when the substrate is present in large excess. Further goals are assessment of the products, their formation yields as well as the kinetic parameters of the considered reaction. The reaction of ozone with 1-propanol in aqueous solution occurs via hydride transfer, H-abstraction and insertion. Of these three mechanisms, the largest share is for hydride transfer. This implies the extraction of an hydride ion from the activated C-H group by O3 according to reaction: (C2H5)(H)(HO)C-H + O3 ? [(C2H5)(H)(HO)C+ + HO3-]cage ? (C2H5)(H)(HO)C+ + HO3-. The experimentally determined products and their overall formation yields with respect to ozone are: propionaldehyde-(60 ± 3)%, propionic acid-(27.4 ± 1.0)%, acetaldehyde-(4.9 ± 0.3)%, acetic acid-(0.3 ± 0.1)%, formaldehyde-(1.0 ± 0.1)%, formic acid-(4.6 ± 0.3)%, hydrogen peroxide-(11.1 ± 0.3)% and hydroxyl radical-(9.8 ± 0.3)%. The reaction of ozone with 1-propanol in aqueous media follows a second order kinetics with a reaction rate constant of (0.64 ± 0.02) M-1·s-1 at pH = 7 and 23 °C. The dependence of the second order rate constant on temperature is described by the equation: l n   k I I = ( 27.17 ± 0.38 ) - ( 8180 ± 120 ) × T - 1 , which gives the activation energy, Ea = (68 ± 1) kJ mol-1 and pre-exponential factor, A = (6.3 ± 2.4) × 1011 M-1 s-1. The nature of products, their yields and the kinetic data can be used in water treatment. The fact that the hydride transfer is the main pathway in the 1-propanol/ozone system can probably be transferred on other systems in which the substrate is characterized by C-H active sites only.

| S-EPMC6747496 | biostudies-literature

Aqueous NMR Signal Enhancement by Reversible Exchange in a Single Step Using Water-Soluble Catalysts.

Project description:Two synthetic strategies are investigated for the preparation of water-soluble iridium-based catalysts for NMR signal amplification by reversible exchange (SABRE). In one approach, PEGylation of a variant N-heterocyclic carbene provided a novel catalyst with excellent water solubility. However, while SABRE-active in ethanol solutions, the catalyst lost activity in >50% water. In a second approach, synthesis of a novel di-iridium complex precursor where the cyclooctadiene (COD) rings have been replaced by CODDA (1,2-dihydroxy-3,7-cyclooctadiene) leads to the creation of a catalyst [IrCl(CODDA)IMes] that can be dissolved and activated in water-enabling aqueous SABRE in a single step, without need for either an organic cosolvent or solvent removal followed by aqueous reconstitution. The potential utility of the CODDA catalyst for aqueous SABRE is demonstrated with the ∼(-)32-fold enhancement of 1H signals of pyridine in water with only 1 atm of parahydrogen.

| S-EPMC4918635 | biostudies-literature

Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media.

Project description:Aggregation and self-assembly are influenced by molecular interactions. With precise control of molecular interactions, in this study, a wide range of nanostructures ranging from zero-dimensional nanospheres to hierarchical nanoplates and spindles have been successfully synthesized at ambient temperature in aqueous solution. The nanostructures reported here are formed by aggregation of spherical seed particles (monomers) in presence of quaternary ammonium salts. Hydroxide ions and a magnetic moment of the monomers are essential to induce shape anisotropy in the nanostructures. The cobalt nanoplates are studied in detail, and a growth mechanism based on collision, aggregation, and crystal consolidation is proposed based on a electron microscopy studies. The growth mechanism is generalized for rods, spindles, and nearly spherical nanostructures, obtained by varying the cation group in the quaternary ammonium hydroxides. Electron diffraction shows different predominant lattice planes on the edge and on the surface of a nanoplate. The study explains, hereto unaddressed, the temporal evolution of complex magnetic nanostructures. These ferromagnetic nanostructures represent an interesting combination of shape anisotropy and magnetic characteristics.

| S-EPMC5331312 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data