Kinetic study of the formation reaction of 3´, 4´-Oisopropylidene- α, β-lactose Received:

Abstract

Gangliosides are complex carbohydrates covalently linked to lipids (glycolipids), which are found in
high concentrations in several types of carcinomas and in lower concentrations in healthy tissue, so that they are
under investigation as essential components of therapeutic vaccines. The ganglioside N-glycolyl GM3 is a major
component of the vaccine for the treatment of breast cancer. This ganglioside is formed by a unit of N-glycolylated
sialic acid, a lactose unit linked to a ceramide and a key intermediate of its synthesis is the acceptor lactose. This
work is focused on obtaining 3',4'-O-isopropylidene-α,β-lactose, the first stage of the synthesis scheme of the
acceptor. In this reaction, besides forming the isomer of interest, are obtained several side products such as 4',6'-Oisopropylidene-
α,β-lactose and mixed acetals, so that the objectives of this work were the study of the kinetics of the
reaction and determining the effect of the variables temperature, time and way of addition of dimethoxypropane
(DMP) on the formation of isomers 3',4' and 4',6'-O-isopropylidene-α,β-lactose in order to find the most suitable
reaction conditions for obtaining the compound of interest. By performing an experimental design, it was
demonstrated that the highest concentration of 3',4'-O-isopropylidene-α,β-lactose is achieved when the reaction is
carried out at 95 ° C, for 45 min. and adding once the DMP .