Regioselectivity of Esterification of Lactose with Fatty Acid via the Stannylene Acetal Method

Abstract

Regioselectivity of lactose esterification with fatty acid using dibutyltin dimethoxide as stannylating agent were probed. The general factors affecting regioselectivity have been examined. The result shows the C-3' position of galactose and the b anomer of C-1 position of the glucose residue have some advantage of being acylated at the condition of N-methyl-1-pyrrolidione as solvent and lower temperature (-15 ºC), the corresponding isomers of lactose fatty acid esters were separated by preparative HPLC method. Explanations for the regioselectivities observed during this tin-mediated reaction were also proposed based on the stannylene acetal in solution.