نتایج جستجو برای: deprotonation
تعداد نتایج: 1798 فیلتر نتایج به سال:
Deprotonation with strong bases of N-vinyl ureas carrying an N'-aryl substituent leads to migration of the N'-aryl group from N to C via an allyllithium; with weaker bases and electron-deficient aryl rings the direction of the migration reverses, and aryl substituents α to the urea N atom may migrate from C to N.
Based on 6-hydroxyindole BODIPY with a Schiff-base structure, NIR fluorescence with impressively high selectivity is triggered by deprotonation of the phenol group upon binding with Zn(2+) due to the chelation-enhanced fluorescence effect, thus realizing a promising application in bioimaging of Zn(2+).
The synthesis of a new type of pentacyclic benzothiazolium compound 6,13-dihydropyrazino[2,1-b:5,4-b ́]bis(1,3-benzothiazole)-7,14-diiumdibromide (2), is reported. Compound 2 was prepared by dimerization of 2-(bromomethyl)benzothiazole. Quantum chemical calculation studies have been carried out on the structures of possible isomers of 2, as well as the products of its deprotonation reactions.
The chiral base n-BuLi/(-)-sparteine or n-BuLi/(+)-sparteine surrogate promotes kinetic resolution of N-Boc-2-arylpiperidines by asymmetric deprotonation. The enantioenriched starting material was recovered with yields 39-48% and ers up to 97 : 3. On lithiation then electrophilic quench, 2,2-disubstituted piperidines were obtained with excellent yields and enantioselectivities.
The trimetallic complex [{CpMn(μ-OSiPh3)2}2Mn] (1) and the heterocubane [CpMn(μ3-SSiPh3)]4 (2) are formed by deprotonation of Ph3SiQH (Q = O, S) by manganocene, or by transmetallation of manganocene by Ph3SiQLi. The Mn(II) centres in 1 and 2 are antiferromagnetically coupled, with J = −4.4 and −3.0 cm(−1) in 1 and 2, respectively (−2J formalism).
We present an easy method for the synthesis of β-ketoesters starting from various carbocyclic and heterocyclic carboxylic acids and esters. The β-ketoester side-chain was introduced by a sequence involving α-deprotonation and quenching with CO2, conversion to the corresponding acid chloride and subsequent chain elongation using deprotonated ethyl acetate.
A dinuclear copper(II) complex of 3,5-diamino-1,2,4-triazole is one of the highly active copper-based catalysts for the oxygen reduction reaction (ORR) in basic solutions. Our in situ X-ray absorption near edge structure measurements revealed that deprotonation of the triazole ligand might cause coordination geometrical changes, resulting in the enhancement of the ORR activity.
QM/MM modelling of FAAH inactivation by O-biphenyl-3-yl carbamates identifies the deprotonation of Ser241 as the key reaction step, explaining why FAAH is insensitive to the electron-donor effect of conjugated substituents; this may aid design of new inhibitors with improved selectivity and in vivo potency.
[reaction: see text] We describe methodology for the in situ generation of reactive monosubstituted ketenes from acid chlorides through a shuttle deprotonation process using NaH as an inexpensive stoichiometric base and a crown ether cocatalyst. We have successfully applied this new procedure to the catalytic, asymmetric synthesis of beta-lactams and alpha-haloesters.
The lithium corrole complex (Mes(2)(p-OMePh)corrole)Li(3)·6THF (1·6THF), prepared via deprotonation of the free-base corrole with lithium amide, acts as precursor for the preparation of cyclopentadienyl zirconium(iv) corrole (2) and pentamethylcyclopentadienyl titanium(IV) corrole (3).
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