Borate esters of the methyl d-glucopyranosides

Methyl α- and β-d-glucopyranoside act as moderate chelators of a boron centre through their O-4/6 binding site whereas the trans/trans arrangement of the O-2/3/4 hydroxy functions is not suited to form a chelate with the small boron central atom. In this work we report the crystal structure of the bisdiolatoborate Na2[B(Me α-d-Glcp4,6H−2)(Me α-d-Glcp3,4,6H−3)]·NaOH·8H2O (1) along with a combined 11B and 13C NMR spectroscopic studies of borate–pyranoside solutions at different concentrations and pH. It is shown that crystallisation of a bisdiolatoborate needs both a high pH and a high total concentration.

Figure optionsDownload as PowerPoint slide