Boronic acid receptors for alpha-hydroxycarboxylates: high affinity of Shinkai's glucose receptor for tartrate.

The glucose receptor 1 developed by Shinkai was synthesized by known methods and with modifications involving the final synthetic step, installation of the phenylboronic acid moieties. Binding of the bis(alpha-hydroxycarbolxylate), tartrate, was assessed and compared to the corresponding bis(diol), erythritol, as well as the corresponding mono(alpha-hydoxycarboxylate), malate. These results suggest that bisboronate/bis(alpha-hydoxycarboxylate) interactions are stronger than the corresponding bisboronate/bis(diol) interactions. Furthermore, we report that the receptor is an order of magnitude more selective for tartrate than malate.