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

Crystals of K[B(AnErytH−2)2]·2 H2O (AnEryt=1,4-anhydroerythritol) form from aqueous alkaline solutions containing a double molar amount of diol over borate. The spiro-type monoanions are the main borate species in the mother liquors of crystallisation according to 11B and 13C NMR spectroscopy. Ribofuranosides form analogous borate esters using their 1,4-anhydroerythritol core. Crystals of Na[B(Meβ-d-Ribf 2,3H−2)2]·2 H2O were grown from alkaline methyl β-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 β-d-ribofuranoside and guanosine.