mt9b01123_si_001.pdf (4.12 MB)
pKa Modulation of Pyrrolidine-Based Catalytic Polymers Used for the Preparation of Glycosyl Hydrazides at Physiological pH and Temperature
journal contribution
posted on 2020-03-10, 17:50 authored by Emily
L. Vargas, J. Antonio Velázquez, Eduardo Rodrigo, Helmut Reinecke, Juan Rodríguez-Hernández, Alfonso Fernández-Mayoralas, Alberto Gallardo, María Belén CidInspired by the ability
of enzymes to use the surrounding hydrophobic
and/or polarizable groups to modulate the pKa of a given amino acid, we designed a series of soluble polymers
able to decrease the basicity of pyrrolidine (from 11.2 to 8.6 pKa units), which clearly increases its aminocatalytic
activity at physiological pH in CN bond formation reactions
via ion iminium activation. Other parameters such as charge density,
hydrophobic/hydrophilic balance, and aggregation state have been studied
as important factors in the catalytic activity of the polymers for
a given substrate. To demonstrate the utility of our approach, an
optimal pyrrolidine-based catalytic polymer has been used for the
formation of C–N bonds between hydrazides and free sugars as
the model system for the preparation of glycoconjugates.