Dependence of the wittig reaction mechanism on the environment and on the substituents at the aldehyde group and at the phosphonium ylide

2010 ◽  
Vol 110 (3) ◽  
pp. 765-776 ◽  
Author(s):  
Giuliano Alagona ◽  
Caterina Ghio
Keyword(s):  
Reaction Mechanism ◽  
Wittig Reaction ◽  
Aldehyde Group

ChemInform Abstract: The Modern Interpretation of the Wittig Reaction Mechanism

ChemInform ◽  
2013 ◽  
Vol 44 (41) ◽  
pp. no-no
Author(s):  
Peter A. Byrne ◽  
Declan G. Gilheany
Keyword(s):  
Reaction Mechanism ◽  
Wittig Reaction

scholarly journals The modern interpretation of the Wittig reaction mechanism

2013 ◽  
Vol 42 (16) ◽  
pp. 6670 ◽  
Author(s):  
Peter A. Byrne ◽  
Declan G. Gilheany
Keyword(s):  
Reaction Mechanism ◽  
Wittig Reaction

scholarly journals A Wittig-olefination–Claisen-rearrangement approach to the 3-methylquinoline-4-carbaldehyde synthesis

2012 ◽  
Vol 8 ◽  
pp. 1725-1729 ◽  
Author(s):  
Mukund G Kulkarni ◽  
Mayur P Desai ◽  
Deekshaputra R Birhade ◽  
Yunus B Shaikh ◽  
Ajit N Dhatrak ◽  
...  
Keyword(s):  
Efficient Method ◽  
Wittig Reaction ◽  
Claisen Rearrangement ◽  
Aldehyde Group ◽  
Oxidative Cleavage ◽  
Reductive Cyclization ◽  
Vinyl Ethers ◽  
Terminal Olefin ◽  
Wittig Olefination ◽  
Step Procedure

Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a–h from o-nitrobenzaldehydes 1a–h employing a Wittig-olefination–Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a–h, which on heating under reflux in xylene underwent Claisen rearrangement to give 4-pentenals 3a–h. Protection of the aldehyde group of the 4-pentenals as acetals 4a–h and subsequent oxidative cleavage of the terminal olefin furnished nitroaldehydes 5a–h. Reductive cyclization of these nitroaldehydes yielded the required 3-methylquinoline-4-carbaldehydes 6a–h in excellent yields. Therefore, an efficient method was developed for the preparation of 3-methylquinoline-4-carbaldehydes from o-nitrobenzaldehydes in a simple five-step procedure.

scholarly journals Exploring inhibition of Pdx1, a component of the PLP synthase complex of the human malaria parasite Plasmodium falciparum

2012 ◽  
Vol 449 (1) ◽  
pp. 175-187 ◽  
Author(s):  
Shaun B. Reeksting ◽  
Ingrid B. Müller ◽  
Pieter B. Burger ◽  
Emmanuel S. Burgos ◽  
Laurent Salmon ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Reaction Mechanism ◽  
Aldehyde Group ◽  
Dependent Manner ◽  
Transgenic Cell ◽  
Ic50 Value ◽  
Parasite Plasmodium ◽  
Parasite Plasmodium Falciparum ◽  
Imine Bond

Malaria tropica is a devastating infectious disease caused by Plasmodium falciparum. This parasite synthesizes vitamin B6de novo via the PLP (pyridoxal 5′-phosphate) synthase enzymatic complex consisting of PfPdx1 and PfPdx2 proteins. Biosynthesis of PLP is largely performed by PfPdx1, ammonia provided by PfPdx2 subunits is condensed together with R5P (D-ribose 5-phosphate) and G3P (DL-glyceraldehyde 3-phosphate). PfPdx1 accommodates both the R5P and G3P substrates and intricately co-ordinates the reaction mechanism, which is composed of a series of imine bond formations, leading to the production of PLP. We demonstrate that E4P (D-erythrose 4-phosphate) inhibits PfPdx1 in a dose-dependent manner. We propose that the acyclic phospho-sugar E4P, with a C1 aldehyde group similar to acyclic R5P, could interfere with R5P imine bond formations in the PfPdx1 reaction mechanism. Molecular docking and subsequent screening identified the E4P hydrazide analogue 4PEHz (4-phospho-D-erythronhydrazide), which selectively inhibited PfPdx1 with an IC50 of 43 μM. PfPdx1 contained in the heteromeric PLP synthase complex was shown to be more sensitive to 4PEHz and was inhibited with an IC50 of 16 μM. Moreover, the compound had an IC50 value of 10 μM against cultured P. falciparum intraerythrocytic parasites. To analyse further the selectivity of 4PEHz, transgenic cell lines overexpressing PfPdx1 and PfPdx2 showed that additional copies of the protein complex conferred protection against 4PEHz, indicating that the PLP synthase is directly affected by 4PEHz in vivo. These PfPdx1 inhibitors represent novel lead scaffolds which are capable of targeting PLP biosynthesis, and we propose this as a viable strategy for the development of new therapeutics against malaria.

On the synthesis and the mechanism of formation of halogenated enol lactones

1997 ◽  
Vol 75 (10) ◽  
pp. 1322-1330 ◽  
Author(s):  
Margaret M. Kayser ◽  
Jun Zhu ◽  
Donald L. Hooper
Keyword(s):  
Reaction Mechanism ◽  
Organic Synthesis ◽  
Wittig Reaction ◽  
Biological Properties ◽  
Mechanism Of Formation ◽  
Direct Route ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

The synthesis of halo enol lactones from cyclic anhydrides via lactonization of the corresponding keto phosphoranes provides a direct route to these interesting compounds, which possess important biological properties and are useful intermediates in organic synthesis. In this paper we outline the syntheses of several halo enol lactones and discuss mechanistic consequences of these reactions on the understanding of Wittig reactions with cyclic anhydrides. Keywords: halolactonization, cyclic anhydrides, halo enol lactones, Wittig reaction mechanism.

Wittig reaction mechanism confirmed

1984 ◽  
Vol 62 (13) ◽  
pp. 30
Keyword(s):  
Reaction Mechanism ◽  
Wittig Reaction

Aldehyde gold clusters for molecular labeling

1995 ◽  
Vol 53 ◽  
pp. 858-859
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya
Keyword(s):  
Covalent Bond ◽  
Aldehyde Group ◽  
Gold Clusters ◽  
Side Reactions ◽  
Amino Groups ◽  
Sodium Cyanoborohydride ◽  
Schiff’S Base ◽  
Protein Molecules ◽  
Hydroxysuccinimide Esters ◽  
Primary Amino

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

2021 ◽  
Author(s):  
Tomasz J. Idzik ◽  
Zofia M. Myk ◽  
Łukasz Struk ◽  
Magdalena Perużyńska ◽  
Gabriela Maciejewska ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Multinuclear Nmr ◽  
Mechanistic Insight ◽  
Nmr Study ◽  
Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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