Design of Boronic Acid-Base Complexes as Reusable Homogeneous Catalysts in Dehydrative Condensations between Carboxylic Acids and Amines

2017 ◽  
Vol 6 (9) ◽  
pp. 1191-1194 ◽  
Author(s):  
Yanhui Lu ◽  
Ke Wang ◽  
Kazuaki Ishihara
Keyword(s):  
Carboxylic Acids ◽  
Boronic Acid ◽  
Acid Base ◽  
Homogeneous Catalysts

Theoretical Studies of the Acid-Base Equilibria in a Model Active Site of the Human 20S Proteasome

2020 ◽  
Author(s):  
Jon Uranga ◽  
Lukas Hasecke ◽  
Jonny Proppe ◽  
Jan Fingerhut ◽  
Ricardo A. Mata
Keyword(s):  
Active Site ◽  
Boronic Acid ◽  
Computational Study ◽  
Ubiquitin Proteasome System ◽  
Bayesian Optimization ◽  
Inhibition Mechanism ◽  
20S Proteasome ◽  
Acid Base ◽  
Ubiquitin Proteasome ◽  
Infection Cycles

The 20S Proteasome is a macromolecule responsible for the chemical step in the ubiquitin-proteasome system of degrading unnecessary and unused proteins of the cell. It plays a central role both in the rapid growth of cancer cells as well as in viral infection cycles. Herein, we present a computational study of the acid-base equilibria in an active site of the human proteasome, an aspect which is often neglected despite the crucial role protons play in the catalysis. As example substrates, we take the inhibition by epoxy and boronic acid containing warheads. We have combined cluster quantum mechanical calculations, replica exchange molecular dynamics and Bayesian optimization of non-bonded potential terms in the inhibitors. In relation to the latter, we propose an easily scalable approach to the reevaluation of non-bonded potentials making use of QM/MM dynamics information. Our results show that coupled acid-base equilibria need to be considered when modeling the inhibition mechanism. The coupling between a neighboring lysine and the reacting threonine is not affected by the presence of the inhibitor.

scholarly journals Effect of intercalator and Lewis acid–base branched peptide complex formation: boosting affinity towards HIV-1 RRE RNA

MedChemComm ◽  
2016 ◽  
Vol 7 (7) ◽  
pp. 1436-1440 ◽  
Author(s):  
Jessica E. Wynn ◽  
Wenyu Zhang ◽  
Denis M. Tebit ◽  
Laurie R. Gray ◽  
Marie-Louise Hammarskjold ◽  
...  
Keyword(s):  
Complex Formation ◽  
Lewis Acid ◽  
Boronic Acid ◽  
Peptide Library ◽  
Acid Base ◽  
Peptide Complex ◽  
Hiv 1

Screening of a boronic acid and acridine containing branched peptide library revealed compounds that bind HIV-1 RRE RNA and inhibit HIV-1 replication.

scholarly journals Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Enrico Prenesti ◽  
Silvia Berto ◽  
Simona Toso ◽  
Pier Giuseppe Daniele
Keyword(s):  
Ionic Strength ◽  
Carboxylic Acids ◽  
Ionic Species ◽  
White Wine ◽  
Chemical Model ◽  
Water Mixture ◽  
Acid Base ◽  
Chemical Equilibria ◽  
Chemical Modelling ◽  
Strong Electrolytes

A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing.

scholarly journals Boronic acid–DMAPO cooperative catalysis for dehydrative condensation between carboxylic acids and amines

2016 ◽  
Vol 7 (2) ◽  
pp. 1276-1280 ◽  
Author(s):  
Kazuaki Ishihara ◽  
Yanhui Lu
Keyword(s):  
Carboxylic Acids ◽  
Boronic Acid ◽  
Condensation Reaction ◽  
Arylboronic Acid ◽  
Cooperative Catalysis ◽  
Individual Use

Arylboronic acid and DMAPO cooperatively catalyse the dehydrative condensation reaction between carboxylic acids and amines to give the corresponding amides under azeotropic reflux conditions. This cooperative use is much more effective than their individual use as catalysts.

The ortho-substituent on 2,4-bis(trifluoromethyl)phenylboronic acid catalyzed dehydrative condensation between carboxylic acids and amines

2018 ◽  
Vol 54 (43) ◽  
pp. 5410-5413 ◽  
Author(s):  
Ke Wang ◽  
Yanhui Lu ◽  
Kazuaki Ishihara
Keyword(s):  
Carboxylic Acids ◽  
Boron Atom ◽  
Boronic Acid ◽  
Phenylboronic Acid ◽  
Acid Catalyzed ◽  
Ortho Substituent

The ortho-substituent of boronic acid plays a key role in preventing the coordination of amines to the boron atom.

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