نتایج جستجو برای: tertiary amine
تعداد نتایج: 101914 فیلتر نتایج به سال:
A simple and convenient method was developed for the preparation of hindered tertiary amines via direct reductive amination of ketones with secondary aryl amines, using trichlorosilane as reducing agent and tetramethylethylenediamine (TMEDA) as organic Lewis base activator. A broad range of ketones were reacted with N-methylaniline to afford the corresponding tertiary amine products in high yie...
Click reactions have provided access to an array of remarkably complex polymer architectures. However, the term "click" is often applied inaccurately to polymer ligation reactions that fail to respect the criteria that typify a true "click" reaction. With the purpose of providing a universal way to benchmark polymer-polymer coupling efficiency at equimolarity and thus evaluate the fulfilment of...
This paper describes an investigation of the uptake of Cu(II) by poly(amidoamine) (PAMAM) dendrimers with an ethylenediamine (EDA) core in aqueous solutions. We use bench scale measurements of proton and metal ion binding to assess the effects of (i) metal ion-dendrimer loading, (ii) dendrimer generation/terminal group chemistry, and (iii) solution pH on the extent of binding of Cu(II) in aqueo...
We characterized the dissociation of polymer/DNA polyplexes designed for gene delivery using water-soluble quantum dots (QDs). A pH-responsive pentablock copolymer was designed to form stable complexes with plasmid DNA via tertiary amine segments. Dissociation of the polyplex was induced using chloroquine where the efficiency of this process was sensed through changes in QD fluorescence. We fou...
In the title compound, C(21)H(21)N(3)O(2), the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3) and 49.6 (3)°, while the dihedral angle between the pyridine rings is 69.7 (3)°. The mol-ecular conformation is stabilized by intramolecular bifurcated O-H⋯N...
Towards a General Understanding of Carbonyl‐Stabilised Ammonium Ylide‐Mediated Epoxidation Reactions
The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high y...
A biomimetic TK one-pot reaction using hydroxypyruvate and aldehydes to generate α,α'-dihydroxy ketones in water has recently been described. To investigate this tertiary-amine mediated reaction mechanism two approaches were used. Firstly, (13)C labelled lithium hydroxypyruvate was synthesised and used to establish where hydroxypyruvate is incorporated in the product. In separate experiments re...
In the title compound, C24H40N4S3 (4+)·2SiF6 (2-)·3CH3OH, the central tertiary amine function is protonated and is connected to three thio-phen-2-yl-methyl-amino-n-propyl groups, forming the arms of a T-shaped cation that has two pockets. Each arm contains one protonated secondary amine function, and each pocket is occupied by one SiF6 (2-) anion bonded via two N-H⋯F inter-actions with the prot...
The selective C–H carbonylation of methylene bonds in the presence of traditionally more reactive methyl C–H and C(sp)–H bonds in a-tertiary amines is reported. The exceptional selectivity is driven by the bulky a-tertiary aminemotif, which we hypothesise orientates the activating C–H bond proximal to Pd in order to avoid an unfavourable steric clash with a second a-tertiary amine on the Pd cen...
Effect of the basic property of reactants (tertiary amine catalysts, a substrate amine, and acid neutralizers) on catalytic dehydrocondensation between a carboxylic acid and an amine by using 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) was studied. The reaction yield was affected by the acid-base equilibrium among reactants. In dichloromethane, a representative aprotic solvent, a strongly basi...
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