scholarly journals Studies of inositol analogues as inhibitors of the phosphoinositide pathway, and incorporation of 2-deoxy-2-fluoro-myo-inositol to give analogues of phosphatidylinositol intermediates

1991 ◽  
Vol 277 (2) ◽  
pp. 407-412 ◽  
Author(s):  
F McPhee ◽  
C P Downes ◽  
G Lowe
Keyword(s):  
Kinetic Analysis ◽  
Exchange Reaction ◽  
The Other ◽  
Exchange Reactions ◽  
Reaction Conditions ◽  
Competitive Inhibitors ◽  
Substantial Inhibition ◽  
Phosphoinositide Pathway

The incorporation of [3H]Ins into PtdIns by exchange of free and lipid-bound inositol moieties occurs via the action of at least two types of Mg2+/Mn(2+)-dependent enzymes in turkey erythrocytes. One is a nucleotide-independent PtdIns/Ins exchange enzyme and its function is, as yet, unknown, whereas the other is CMP-dependent and appears to be an exchange reaction catalysed by PtdIns synthase. The effects of analogues with modifications of the substituent at the 1-, 2-, 3-, 4- and 5-positions on the incorporation of [3H]Ins into PtdIns under both synthase and exchange reaction conditions were investigated in turkey erythrocytes. Analogues causing substantial inhibition of [3H]Ins incorporation were then used in kinetic experiments to determine the type of inhibition involved. The analogues 1-deoxy-1-fluoro-scyllo-inositol and 5-O-methyl-myo-inositol exhibited the greatest effects on the incorporation of [3H]Ins via both the synthase and exchange reactions, and the kinetic analysis indicated that they were competitive inhibitors of Ins. Ki values of 0.37 mM and 2.87 mM were observed for 1-deoxy-1-fluoro-scyllo-inositol under exchange and synthase reaction conditions respectively; similar Ki values of 0.26 mM and 2.80 mM were observed for 5-O-methyl-myo-inositol in the exchange and synthase reactions respectively. The ability of 1-deoxy-1-fluoro-scyllo-inositol and its diastereoisomer, 2-deoxy-2-fluoro-myo-inositol, to act as substrates for the synthase and exchange reactions in turkey erythrocytes was investigated. The radiolabelled derivative of the former analogue was not incorporated into phospholipids, whereas the radiolabelled derivative of the latter analogue was a poor substrate for the synthase and exchange enzymes. In the presence of ATP, the labelled analogue of PtdIns, derived from 2-deoxy-2-fluoro-myo-[2-3H]inositol, appeared to be converted into phosphorylated PtdIns analogues, presumably by the enzymes of the phosphoinositide pathway.

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur
Keyword(s):  
Supramolecular Chemistry ◽  
Sulfonic Acid ◽  
Catalytic Efficiency ◽  
The Other ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bioactive Scaffolds ◽  
Wide Range ◽  
Efficient Alternative ◽  
Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

Preparation of Functionalized Diorganomagnesium Reagents in Toluene via Bromine or Iodine/Magnesium-Exchange Reactions

Synthesis ◽  
2021 ◽  
Author(s):  
Alexandre Desaintjean ◽  
Fanny Danton ◽  
Paul Knochel
Keyword(s):  
Exchange Reaction ◽  
Nitro Group ◽  
General Formula ◽  
Functional Groups ◽  
Exchange Reactions ◽  
Acyl Chlorides ◽  
Aryl Iodides ◽  
Highly Sensitive ◽  
Wide Range ◽  
Magnesium Exchange

A wide range of polyfunctionalized di(hetero)aryl- and dialkenyl-magnesium reagents were prepared in toluene within 10 to 120 min between −78 °C and 25 °C via an I/Mg- or Br/Mg-exchange reaction using reagents of the general formula R2Mg (R = sBu, Mes). Highly sensitive functional groups, such as a triazene or a nitro group, were tolerated in these exchange reactions, enabling the synthesis of various functionalized (hetero)arenes and alkenes derivatives after quenching with several electrophiles including allyl bromides, acyl chlorides, aldehydes, ketones, and aryl iodides.

THEORETICAL STUDIES ON THE COUPLING INTERACTIONS AND SELF-EXCHANGE REACTION MECHANISMS IN THE COMPLEXES OF NO WITH ONH AND NOH

2008 ◽  
Vol 07 (03) ◽  
pp. 435-446 ◽  
Author(s):  
PING LI ◽  
XIAOYAN XIE ◽  
YUXIANG BU ◽  
WEIHUA WANG ◽  
NANA WANG ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Exchange Reaction ◽  
Reaction Mechanisms ◽  
Natural Bond Orbital ◽  
Theoretical Studies ◽  
Exchange Reactions ◽  
Electron Transfer Mechanism ◽  
Proton Coupled Electron Transfer ◽  
Planar Geometries ◽  
Transfer Mechanisms

The coupling interactions and self-exchange reaction mechanisms between NO and ONH (NOH) have been systematically investigated at the B3LYP/6-311++G** level of theory. All the equilibrium complexes are characterized by the intermolecular H-bonds and co-planar geometries. The cisoid NOH/ON species is the most stable one among all the complexes considered due to the formation of an N – N bond. Moreover, all the cisoid complexes are found to be more stable than the corresponding transoid ones. The origin of the blueshifts occurring in the selected complexes has been explored, employing the natural bond orbital (NBO) calculations. Additionally, the proton transfer mechanisms for the self-exchange reactions have been proposed, i.e. they can proceed via the three-center proton-coupled electron transfer or five-center cyclic proton-coupled electron transfer mechanism.

An all-in-one approach for synthesis and functionalization of nano colloidal gold with acetylacetone

2021 ◽  
Author(s):  
Li Zhang ◽  
Hongcen Zheng ◽  
Yonghai Gan ◽  
Bingdang Wu ◽  
Zhihao Chen ◽  
...  
Keyword(s):  
Exchange Reaction ◽  
Ligand Exchange ◽  
Fold Increase ◽  
Charge Transfer Complexes ◽  
Photochemical Property ◽  
Exchange Reactions ◽  
Ligand Exchange Reaction ◽  
Enhanced Photoluminescence ◽  
Good Imaging ◽  
Imaging Probes

Abstract Controllable synthesis, proper dispersion, and feasible functionalization are crucial requirements for the application of nanomaterials in many scenarios. Here, we report an all-in-one approach for the synthesis and functionalization of gold nanoparticles (AuNPs) with the simplest β-diketone, acetylacetone (AcAc). With this approach, the particle size of the resultant AuNPs was tunable by simply adjusting the light intensity or AcAc dosage. Moreover, owing to the capping role of AcAc, the resultant AuNPs could be stably dispersed in water for a year without obvious change in morphology and photochemical property. Formation of ligand to metal charge transfer complexes was found to play an important role in the redox conversion of Au with AcAc. Meanwhile, the moderate complexation ability enables the surface AcAc on the AuNPs to undergo ligand exchange reactions. With the aid of Ag+, the AuNPs underwent ligand exchange reaction with glutathione and exhibited enhanced photoluminescence (PL) with a maximum of 22-fold increase in PL intensity. The PL response was linear to the concentration of glutathione in the range of 0~500 μM. Such a ligand exchange reaction makes the obtained AuNPs being good imaging probes. To the best of our knowledge, this is the first work on illustrating the roles of AcAc as a multifunctional ligand in fabrication of NPs, which sheds new light on the surface modulation in synthesis of nanomaterials.

STUDIES ON THE BIOSYNTHESIS OF NUCLEOTIDES IN EHRLICH ASCITES CARCINOMA CELLS IN VITRO

1965 ◽  
Vol 43 (2) ◽  
pp. 209-224 ◽  
Author(s):  
B. I. Uppin ◽  
P. G. Scholefield
Keyword(s):  
Exchange Reaction ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
The Other ◽  
Metabolic Inhibitors ◽  
Ehrlich Ascites ◽  
Oxidative Pathway ◽  
Time Courses ◽  
Oxidation Of Glucose

Studies have been made of the effects of metabolic inhibitors on the oxidation and incorporation of radioactivity into nucleotides of glucose labelled in the 1, 2, and 6 positions. The results indicate that in Ehrlich ascites carcinoma cells the predominant oxidative pathway is the hexosemonophosphate shunt. Investigation of the time courses of oxidation of the labelled glucose molecules confirms this conclusion. The pattern of incorporation of radioactivity initially suggests that nucleotide ribose is not formed via this pathway. However, it is shown that the coupling of an active transketolase system with the other enzymes of the hexosemonophosphate shunt provides a sufficient explanation of all the experimental observations. The conclusion is reached that pentose is formed by oxidation of glucose through the shunt but that the labelling pattern is largely established as the result of the exchange reaction catalyzed by transketolase.

scholarly journals Regioselective Synthesis of 5-Propyl-2-((trityloxy)methyl)thiophene-3-carbaldehyde

Molbank ◽  
10.3390/m1289 ◽  
2021 ◽  
Vol 2021 (4) ◽  
pp. M1289
Author(s):  
Sukanta Bar
Keyword(s):  
Exchange Reaction ◽  
Regioselective Synthesis ◽  
Exchange Reactions ◽  
Halogen Exchange

5-propyl-2-((trityloxy)methyl)thiophene-3-carbaldehyde was synthesized by using the concept of chemo- and regioselective Br/Li exchange reaction from 3-bromo-5-propyl-2-((trityloxy)methyl)thiophene. This is a five-step protocol starting from thiophene with an overall yield of 33%. These lithium/halogen exchange reactions were carried out at −78 °C to rt over the period of 1 to 18 h depending on the reactivity of electrophiles.

scholarly journals Darstellung und Charakterisierung von Tetrabutylammonium-Tetraiodooxotechnetat(V), (TBA) [TcOI4] / Preparation and Characterization of Tetrabutylammonium Tetraiodooxotechnetate(V), (TBA)[TcOI4]

1981 ◽  
Vol 36 (2) ◽  
pp. 138-140 ◽  
Author(s):  
G. Peters ◽  
W. Preetz
Keyword(s):  
Raman Spectrum ◽  
Exchange Reaction ◽  
Vibrational Spectra ◽  
Ligand Exchange ◽  
Resonance Raman ◽  
The Other ◽  
Resonance Raman Spectrum ◽  
Ligand Exchange Reaction ◽  
Complex Ion

Abstract Pure (TBA)[TcOI4] is prepared from (TBA)[TcOCl4] by ligand exchange reaction with Nal in acetone. The vibrational spectra indicate C4v symmetry for the complex ion. On excitation with the 514.5 nm line of an Ar-laser a resonance Raman spectrum is obtained showing v(TcO) = 996 cm-1 and four of its overtones, symmetrically surrounded by groups of bands arising as well from the sums as from the differences of frequencies with the other fundamentals. In contrast to the ligand exchange reaction the reduction of Tc04- with conc. HI yields products always contaminated with polyiodides. The extremely strong Raman scatterer (TBA)l3 is detected by a characteristic doublet at 111 and 116 cm-1 and even small amounts of it cover the Raman spectrum of (TBA)[TcOI4].

Recent Progress in σ-Bond Cross-Exchange Reactions to Access Diverse Silacycles

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2595-2600 ◽  
Author(s):  
Dongbing Zhao ◽  
Wen-Tao Zhao ◽  
Fang Gao
Keyword(s):  
Exchange Reaction ◽  
Recent Progress ◽  
Atom Economy ◽  
Exchange Reactions ◽  
Rapid Access ◽  
Recent Advances

The σ-bond cross-exchange reaction, which involves cleavage and subsequent exchange between different nonpolar σ-bonds, constitutes an attractive protocol for rapid access to organic skeletons with 100% atom economy. Herein, we give a brief summary of recent achievements in this approach for the synthesis of diverse silacycles, highlighting our recent advances in the first intermolecular σ-bond exchange between C–C bonds of cyclopropenones and C–Si bonds of (benzo)silacyclobutanes.1 Introduction2 σ-Bond Exchange-Reaction of Benzocyclobutanones to Silacycles3 σ-Bond Exchange-Reaction of Ethyl Cyclopropylideneacetates to Silacycles4 σ-Bond Exchange-Reaction of Cyclopropenones to Silacycles5 Conclusion

Preparation of (1R )[1—2H]- and (1S)[1—2H]-Alcohols by Exchange Reactions Catalyzed by Yeast or a Coupled Enzyme System

1973 ◽  
Vol 28 (5-6) ◽  
pp. 241-246 ◽  
Author(s):  
Helmut Günther ◽  
Miguel A. Alizade ◽  
Max Kellner ◽  
Florian Biller ◽  
Helmut Simon
Keyword(s):  
Alcohol Dehydrogenase ◽  
Exchange Reaction ◽  
Enzyme System ◽  
Deuterium Oxide ◽  
Exchange Reactions ◽  
Ordinary Water

All possible enantiomers of stereospecifically labelled [1-2H] ethanol, propanol and butanol have been prepared on a scale of up to 7 ml. The R forms have been obtained by incubation of the alcohols with alcohol dehydrogenase and diaphorase (NAD: Lipoamide oxidoreductase, EC 1.6.4.3) in presence of catalytic amounts of NAD+/NADH in deuterium oxide. The S forms have been prepared with the same enzymes in ordinary water, from the corresponding [1,1-2H] alcohols. (IS) [1-2H] ethanol was prepared from [1,1-2H] ethanol and ordinary water, by a yeast catalyzed exchange reaction.

Experimental Research of Decoloring Treatment on Vitamin B12 Wastewater

2013 ◽  
Vol 295-298 ◽  
pp. 1209-1214 ◽  
Author(s):  
Si Hang Shan ◽  
Peng Fei Fan ◽  
Yi Xing ◽  
Geng Qiao
Keyword(s):  
Waste Water ◽  
Vitamin B12 ◽  
Experimental Research ◽  
Removal Rate ◽  
Color Removal ◽  
The Other ◽  
Vitamin B ◽  
Reaction Conditions ◽  
Pharmaceutical Factory

Two kinds of vitamin B12 waste water from a pharmaceutical factory were treated separately by methods of combining micro-electrolysis with physiochemical and O3 oxidation. Effects of the reaction conditions on the removal rate of color were investigated. Results showed that the color removal rate of vitamin B12 waste water, which was treated by combined micro-electrolysis and physiochemical treatment reached 71.25%, while the color removal rate of the other waste water which treated by O3 oxidation reached 68.80%. The decolorizing treatment of those different natures of vitamin B12 waste water effectively provides a useful reference for this kind of waste water.

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