Abstract Dissociation constants of 3-and 4-pyridineboronic acid and σ-values for the meta- and para-B (OH) 2 and-B (OH) 3− groups have been determined; in aqueous solutions the compounds occur predominantly in the pyridiniumboronate form. 2-Pyridineboronate seems to be thermally unstable, whereas 3-and 4-pyridineboronic acids are thermally stable but decompose upon treatment with methyl iodide.
