The Combined Role of Catalysis and Solvent Effects on the Biginelli Reaction: Improving Efficiency and Sustainability

2013 ◽  
Vol 19 (16) ◽  
pp. 5174-5182 ◽  
Author(s):  
James H. Clark ◽  
Duncan J. Macquarrie ◽  
James Sherwood
Keyword(s):  
Solvent Effects ◽  
Biginelli Reaction

Can the Lewis basicity of an isolated solvent molecule be used for characterizing solvent effects?

2020 ◽  
Vol 16 ◽  
Author(s):  
Jean-François Gal ◽  
Pierre-Charles Maria
Keyword(s):  
Solvent Effects ◽  
Molecular Level ◽  
Solvent Molecule ◽  
Lewis Base ◽  
Bulk Liquid ◽  
Donor Number ◽  
Special Focus ◽  
Solution Processes ◽  
Inert Solvent

Background: The ubiquitous Lewis acid/base interactions are important in solution processes. Analytical chemistry may benefit of a better understanding of the role of Lewis basicity, at the molecular level or acting through a bulk solvent effect. Objective: To clearly delineate (i) the basicity at a molecular level, hereafter referred as solute basicity, and (ii) the solvent basicity, which is a bulk-liquid property. Method: The literature that relates Lewis basicity scales and solvent effects is analyzed. A special focus is placed on two extensive scales, the Donor Number, DN, and the BF3 affinity scale, BF3A, which were obtained by calorimetric measurement on molecules as solutes diluted in a quasi-inert solvent, and therefore define a molecular Lewis basicity. We discuss the validity of these solute scales when regarded as solvent scales, in particular when the basicity of strongly associated liquids is discussed. Results: We demonstrate the drawbacks of confusing the Lewis basicity of a solvent molecule, isolated as solute, and that of the bulk liquid solvent itself. Conclusion: Consequently, we recommend a reasoned use of the concept of Lewis basicity taking clearly into account the specificity of the process for which a Lewis basicity effect may be invoked. In particular, the action of the Lewis base, either as an isolated entity, or as a bulk liquid, must be distinguished.

scholarly journals Tuning the Biginelli reaction mechanism by the ionic liquid effect: the combined role of supported heteropolyacid derivatives and acidic strength

RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 27125-27135 ◽  
Author(s):  
Elon F. Freitas ◽  
Roberto Y. Souza ◽  
Saulo T. A. Passos ◽  
José A. Dias ◽  
Silvia C. L. Dias ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Reaction Mechanism ◽  
Biginelli Reaction

Heteropolyacids and ionic liquid effect allowed tuning of the Biginelli reaction mechanism and synthesis of 3,4-dihydropyrimidin-2(1H)-one/thione derivatives in an efficient, recyclable fashion. The role of acidic strength and supported heteropolyacid is disclosed.

Solvent Effects in Carbohydrate Binding by Synthetic Receptors: Implications for the Role of Water in Natural Carbohydrate Recognition

2008 ◽  
Vol 120 (14) ◽  
pp. 2733-2736 ◽  
Author(s):  
Emmanuel Klein ◽  
Yann Ferrand ◽  
Nicholas P. Barwell ◽  
Anthony P. Davis
Keyword(s):  
Solvent Effects ◽  
Carbohydrate Binding ◽  
Synthetic Receptors ◽  
Carbohydrate Recognition

A test of the role of refractive index in correlations between solvent effects on electronic spectra and solvent effects on reaction equilibria and rates

1984 ◽  
Vol 49 (10) ◽  
pp. 2332-2341 ◽  
Author(s):  
Vojtěch Bekárek
Keyword(s):  
Refractive Index ◽  
Solvent Effects ◽  
Electronic Spectra ◽  
Kinetic Data ◽  
Fluorescence Spectra ◽  
Simple Relation ◽  
Absorption And Fluorescence Spectra ◽  
Induced Changes ◽  
Better Than

80 correlations have been carried out between the medium-induced changes in equilibrium and kinetic data (Y) and the medium-induced changes in positions of maxima in electronic (both absorption and fluorescence) spectra (Δν) of the Kamlet-Taft type indicators. The correlations have been carried out by means of the equations Y=Y0 + k . Δν and Y=Y0 + k' . Δν/f(n2) using only the Kamlet-Taft select solvents (SSS). The equation involving the function of refreactive index (n), f(n2) = (n2 - 1)/(2n2 + 1), is better than the simple relation between Y and Δν in 93% of the systems studied. The problem of HBD acidity of nitromethane and the relation of the A and B solvent characteristics by Swain and the characteristics of dipolarity of medium by Kamlet-Taft are discussed.

Sign in / Sign up

Export Citation Format

Share Document