Alkaline Degradation of Monosaccharides VI1: The Fhucto-Fobmose Reaction of Mixtures of D-Fructose and Formaldehyde

Abstract The final product compositions of the alkaline (calcium hydroxide) degradation of D-fructose in the presence of formaldehyde at several D-fructose/formaldehyde ratios, and of the formose reaction were determined by HPLC and GC analysis. At decreasing D-fructose/formaldehyde ratio a gradual change of the composition was observed except for lactic acid and the oligomeric acidic products, which show a minimum and a maximum, respectively. A mechanistic explanation is given by the aldolization of formaldehyde both with saccharides and with their subsequent α-dicarbonyl intermediates, which favours the formation of oligomeric products at the cost of lactic acid. It is established both experimentally and theoretically that there is no essential mechanistic difference between the formose reaction and the alkaline degradation of monosaccharides.