Regioselective enzymatic hydrolysis of acetylated pyranoses and pyranosides using immobilised lipases. An easy chemoenzymatic synthesis of alpha- and beta-D-glucopyranose acetates bearing a free secondary C-4 hydroxyl group.
Protected sugars with only one free hydroxyl group are useful building blocks for the synthesis of a large number of glycoderivatives. In order to avoid the problems of the classical chemical synthesis, we studied the regioselective enzymatic hydrolysis of different fully acetylated glycopyranoses and glycopyranosides. The main challenge was to obtain the hydrolysis of the substrates in only one position, with high regioselectivity, while avoiding any further hydrolysis towards partially acetylated sugars. Candida rugosa (CRL) and Pseudomonas fluorescens (PFL) lipases (EC 3.1.1.3) immobilised on octyl agarose afforded regioselective hydrolysis only in the 6- and 1-positions, respectively. Furthermore, a new one-pot chemoenzymatic approach has been developed in order to obtain alpha- and beta-protected glucopyranoses bearing a free secondary C-4 hydroxyl group. For instance, 1,2,3,6-tetra-O-acetyl-alpha-D-glucopyranose was easily synthesised in good overall yield (70%) starting from 1,2,3,4,6-penta-O-acetyl-alpha-D-glucopyranose by regioselective enzymatic hydrolysis in the 6-position, catalysed by CRL, followed by a temperature- and pH-controlled acyl migration.
Terreni
Marco
M
Department of Pharmaceutical Chemistry, Via Taramelli 12, University of Pavia, Pavia, Italy. markt@pbl.unipv.it
Salvetti
Raul
R
Linati
Laura
L
Fernandez-Lafuente
Roberto
R
Fernández-Lorente
Gloria
G
Bastida
Agatha
A
Guisan
José M
JM
D000085:Acetates / Q000737:chemistry*; D000107:Acetylation; D002175:Candida / Q000201:enzymology; D002384:Catalysis; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000201:enzymology; D011714:Pyrans / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature
D000085:Acetates; D004800:Enzymes, Immobilized; D011714:Pyrans; D008049:Lipase; D005947:Glucose