Preparation of a series of N-alkyl-3-boronopyridinium halides and study of their stability in the presence of hydrogen peroxide

Abstract

A simple and efficient protocol for the preparation of a series of N-alkyl-3-boronopyridinium salts is described which requires exposure of 3-pyridineboronic acid neopentylglycol ester and corresponding alkyle halide to microwave irradiation followed by boronic ester hydrolysis. The technique employed drastically reduces the reaction time and prevents thermal degradation and the formation of side products. Water solutions of the obtained boronopyridinium salts are shown to be stable at room temperature in wide pH range as well as in the presence of hydrogen peroxide at pH 10.0 for 72 h.

Functionalized Vesicles Based on Amphiphilic Boronic Acids: A System for Recognizing Biologically Important Polyols

“…Solvents were purified and dried by standard methods prior to use, when needed. Boronic acids 1 – 3 were synthesized according to the previously reported method. , All solutions were prepared using water from a Millipore UltraPure system (18.2 MΩ·cm). Solutions of compounds 2 and 3 were sonicated for 20 min until they had completely dissolved and then equilibrated at 25 °C in the thermal control unit before running an experiment.…”

“…Surfactants bearing specifically modified moieties, or functionalized surfactants, open opportunities to use the advantages of nonfunctionalized organized molecular systems (bringing together analyte and a sensing molecule in water/micelle or water/vesicle interface) with the high “local” concentration of specific moieties responsible for sensitivity. Recently, we reported simple and efficient methods of synthesis of N -alkyl-3-boronopyridinium triflates and iodides (compounds 2 and 3 in Scheme ). These surfactants are the derivatives of pyridine-3-boronic acid which is known as one of the least basic among aryl boronic acids, its p K a (constant of indirect proton transfer that characterizes the acidity of most boronic acids in water followed by trigonal–tetragonal boron transformation) is as low as ca.…”