A combined X-ray and NMR study of borate esters of furanoidic cis-1,2-diols

摘要

Crystals of K[B(AnErytH_2)_2]centre dot 2 H_2O (AnEryt=1,4-anhydroerythritol) form from aqueous alkaline solutions containing a double molar amount of diol over borate. The spiro-type monanions are the main borate species in the mother liquors of crystallisation according to ~(11)B and ~(13)C NMR spectroscopy. Ribofuranosides form analogous borate esters uisng their 1,4-anhydroerythritiol core. Crystals of Na[B(Me#beta#-D-Ribf 2,3H_2)_2]centre dot 2H_2O were grown from alkaline methyl #beta#-D-ribofuranoside solutions that had attacked boron-containing Duran vessels. NMR spectra show closely resembling borate-ester speciation in solutions of diols with the 1,4-anhydroerythritol core-1,4-anhydroerythritol itself, methyl #beta#-D-ribofuranoside and guanosine.