1. Efficient differentiation of the hydroxyl groups of 3,4-O-isopropylidene-D-galactopyranosides by lipase catalyzed esterification and de-esterification
- Author
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Pier Luigi Barili, Ettore Mastrorilli, Felicia D'Andrea, and Giorgio Catelani
- Subjects
chemistry.chemical_classification ,biology ,DERIVATIVES ,Organic Chemistry ,biology.organism_classification ,Biochemistry ,Medicinal chemistry ,D-GALACTOSE ,chemistry.chemical_compound ,chemistry ,Enzymatic hydrolysis ,Yield (chemistry) ,D-GALACTOSE, DERIVATIVES, ACID ,ACID ,biology.protein ,Vinyl acetate ,Reactivity (chemistry) ,Candida antarctica ,Lipase ,Selectivity ,Alkyl - Abstract
The Pseudomonas sp. (LPS) promoted acyl transfer from vinyl acetate to selected 3,4-O-isopropylidene-D-galactopyranosides takes place in a completely selective manner giving in high yield the corresponding 6-O-acetates. The acetylation rate is strongly dependent on the type and the orientation of the aglycon, varying from a maximum of reactivity for the 1-deoxy derivative, 1,5-anhydro-3,4-O-isopropylidene-D-galactitol (1d), to a minimum for β configurated alkyl glycosides and showing a complete loss of reactivity for 3′,4′:2,3:5,6-tri-O-isopropylidenelactose dimethyl acetal (1e). The latter compound is, however, selectively 6′-O-esterified in good yield by lipase from Candida Antarctica and vinyl acetate. Also the course of the enzymatic hydrolysis of 2,6-di-O-acetyl-3,4-O-isopropylidene-D-galactopyranosides 2 is dependent on the type of the aglycon, both for the reaction rate and the selectivity. The 2-O-acetates 4 are selectively obtained in good yields with porcine pancreatic lipase (PPL) prom...
- Published
- 1997