نتایج جستجو برای: phenacyl isoquinolinium ylide

تعداد نتایج: 762  

2011
Baskar Lakshmanan Papiya Mitra Mazumder D. Sasmal Simon Santosh Jena

Anthelmintic resistance creates a major hitch over the decades throughout the world. As per WHO only few drugs are frequently used in the treatment of helminth infestations in human beings. In view of this, an attempt has been made to study the anthelmintic activity of some newly synthesized 1-substituted imidazoles (1a-1d, 2a-2d) were synthesized and characterized by their spectral data. All t...

2007
Juliana Bodoprost Helmut Rosemeyer

A set of 13 fatty acids was transformed into their phenacyl esters by reaction with phenacyl bromide in acetonitrile using 18-crown-6 as phase-transfer catalyst. Conditions for the RP-18 HPL chromatographic separation of most of the esters has been worked out. Using this standard the fatty acid spectra from skin surface sebum lipids of 17 test persons was taken after microwave-assisted hydrolys...

Journal: :Berichte der deutschen chemischen Gesellschaft 1908

Journal: :Organic and Biomolecular Chemistry 2021

The importance of the relative triplet excited state energies avobenzone (our phenacyl-like photolabile group) and ketoprofen photocaged drug) has been demonstrated by means spectroscopic experiments theoretical calculations.

Journal: :Molecules 2005
Konstantina Spagou Elizabeth Malamidou-Xenikaki Spyros Spyroudis

The phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone reacts with aminoesters, ureas, aminoalcohols and aminophenols in refluxing dichloromethane to afford good yields of indanedione 2-carboxamido compounds, that in solution exist in an enol-amide form. The same reactants in a copper-catalyzed reaction afford mainly the corresponding N-arylo compounds. Arylhydrazines are mainly oxidized by t...

Journal: :Organic letters 2010
Alessandro Piccinini Sarah A Kavanagh Paul B Connon Stephen J Connon

An investigation into the poor activity of sulfides as catalysts for sulfonium-ylide-mediated methylene transfer to aldehydes has indicated that ylide formation is the problematic catalytic cycle step. Alkylation with traditional electrophiles does not proceed with sufficient efficiency to allow the sulfide to be used catalytically. Methyl triflate rapidly alkylates cyclic thiolanes under mild ...

Journal: :Advanced Synthesis & Catalysis 2021

Stabilised sulfur ylides are synthetically appealing compounds, which reactivity under Brønsted acid catalysis has been poorly explored. Herein, we report a new catalyst- and substrate- dependent chemodivergent reaction between stabilised salicylaldehydes, leading to the (suprising) formation of 2H-chromenes or dihydrobenzofurans products. Particular attention was set on unusual mechanisms invo...

2015
Jingjing Wang Samuel Z Y Ting Joanne E Harvey

Bestmann ylide [(triphenylphosphoranylidene)ketene] acts as a chemical linchpin that links nucleophilic entities, such as alcohols or amines, with carbonyl moieties to produce unsaturated esters and amides, respectively. In this work, the formation of α,β,γ,δ-unsaturated esters (dienoates) is achieved through the coupling of Bestmann ylide, an alcohol and an α,β-unsaturated aldehyde. Primary an...

2012
Marc Enßle Stefan Buck Roland Werz Gerhard Maas

Methionine, S-benzylcysteine and S-allylcysteine were converted into 2-diazo-3-oxo-4-phthalimidocarboxylic esters 8a-c in three steps. Upon rhodium-catalysed dediazoniation, two intramolecular carbenoid reactions competed, namely the formation of a cyclic sulfonium ylide and that of a six-ring carbonyl ylide. The S-methyl and S-benzyl ylides 12a and b could be isolated, while S-allyl ylide 12c ...

2007
Mohamed Ebrahim Helen Stoeckli-Evans Krishnaswamy Panchanatheswaran

The unsymmetrical phosphorus ylide, Ph2PCH2CH2PPh2@C(H)C(O)Ph is shown to react with Hg(II) halides to form polymeric products with the composition {HgX2[PPh2CH2CH2PPh2C(H)C(O)Ph]}n, where X = Cl (1), Br (2), I (3). The complexes have been characterized by elemental analysis, IR, H, P NMR spectra as well as by ESI mass spectra. In product 1 the ylide exhibits a P, C-bridging mode of coordinatio...

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