Enzymic Hydrolysis of Acetylated D-Ribose Derivatives

Tetra-O-acetyl-β -D-ribopyranose (1) and tetra-O-acetyl-β -D-ribofuranose (2) were submitted to hydrolysis catalyzed by several hydrolytic enzymes. The best results were achieved with the esterase from rabbit serum (RS), porcine pancreatic lipase (PPL) and porcine liver esterase (PLE). Regioselective enzymic deacetylation of the ester group on the anomeric centre of 1 produced in all three cases 2, 3, 4-tri-O-acetyl-β -D-ribopyranose (3) as the main product. Tetraacetate 2 underwent enzymic hydrolysis followed most probably by acetyl migration and the mixture of two triacetates 1, 2, 5-tri-O-acetyl-β -D-ribofuranose 4 and 1, 3, 5-tri-O-acetyl-β -D-ribofuranose 5 was isolated. Structures of prepared compounds were established by 1H and 13C NMR spectroscopies.