1,3-Di(2-dipyridyl)propan-1,3-dione – a new fluorogenic labeling reagent for milk oligosaccharides

We herein demonstrate the use of 1,3-di(2-dipyridyl)propan-1,3-dione (DPPD) as a fluorogenic label for oligosaccharides. A number of milk-derived oligosaccharide standards were successfully labeled with this reagent, with the advantage of greatly simplified sample preparation compared to other commonly used fluorescent tags. DPPD shows a selectivity for oligosaccharides which do not possess a 2-acetamido-2-deoxy-hexose moiety at the reducing terminus, potentially aiding in the identification of complex mixtures of carbohydrates. The use of DPPD for the structural determination of oligosaccharides through exoglycosidase treatment, quantitative analysis of reactions, and in the synthesis of labeled oligosaccharides was also explored. This reagent has, in addition to the analysis of individual and mixed oligosaccharides, potential applications in the study of glycosidases and glycosyltransferases and as such represents a valuable addition to the tools available to the glycoscientist.