Acid‐catalyzed reductive amination of aldoses with 8‐aminopyrene‐1,3,6‐trisulfonate

Abstract

The reductive amination of monosaccharides with 8‐aminopyrene‐1,3,6‐trisulfonate (APTS) in seven different organic acids including the commonly used acetic acid was investigated by capillary electrophoresis (CE) with laser‐induced fluorescence (LIF) detection. The correlation between the yields of the saccharide‐APTS adducts and pK_a of the organic acid catalyst is consistent with general acid catalysis of the rate‐determining step of the reductive amination reaction. Derivatization in the presence of organic acids of higher strength than acetic acid produced substantially higher yields of APTS‐sugar adducts, an effect which is more pronounced for N‐acetylamino sugars. Optimum yields were obtained using citric acid as a catalyst. Conversion of a few nanomoles of neutral saccharides to the APTS derivatives is achieved at 75°C in less than 60 min.