Related Experiment Video
Updated: Jul 14, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
Carboxylate binding in polar solvents using pyridylguanidinium salts
Richard J Fitzmaurice1, Francesca Gaggini, Natarajan Srinivasan
1School of Chemistry, University of Southampton, Southampton, UK SO17 1BJ.
Abstract:
A series of thiourea and guanidinium derivatives have been prepared and their ability to bind a carboxylate group has been investigated. Guanidinium 33, featuring two additional amides and a pyridine moiety, proved to be the most potent carboxylate binding site and was able to bind acetate in aqueous solvent systems (K(ass) = 480 M(-1) in 30% H(2)O-DMSO). The pyridine moiety is critical to obtaining strong binding, and comparison with the binding properties of analogous compounds in which the pyridine is replaced by a benzene ring provides a striking example of enthalpy-entropy compensation.
Related Concept Videos
Acid Halides to Carboxylic Acids: Hydrolysis
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
Molecular Shape and Polarity
Preparation of Carboxylic Acids: Carboxylation of Grignard Reagents
Basicity of Heterocyclic Aromatic Amines
Acid Halides to Ketones: Gilman Reagent
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen double...
Acid Halides to Esters: Alcoholysis

