Tris Buffer Reactivity with Low-Molecular-Weight Aldehydes: NMR Characterization of the Reactions of Glyceraldehyde-3-Phosphate

Tris (2-amino-2-hydroxymethylpropane-1,3-diol) reacts with aldehydes of low molecular weight in aqueous solutions to give products whose NMR spectral properties are inconsistent with the formation of the expected Schiff base. High-field 1H and 13C NMR spectra of a solution of Tris and glyceraldehyde 3-phosphate indicated initial formation of 2-(β-phosphoglycolyl)-4,4-bis(hydroxymethyl)1,3-oxazolidine, which was then converted to condensation products of Tris and methylglyoxal, accompanied by deuterium exchange when the solvent was 2H2O. Acetaldehyde and benzaldehyde were used as model substrates which yielded more stable oxazolidines in their reactions with Tris.