Stereoselective Synthesis of Quercetin 3-O-Glycosides of 2-Amino-2-Deoxy-d-Glucose Under Phase Transfer Catalytic Conditions

GRAPHICAL ABSTRACT

Abstract

This article describes the stereoselective synthesis of quercetin 3-O-glycosides of 2-amino-2-deoxy-d-glucose. Efficient 1,2-trans-glycosylation of protected quercetin with N-acetyl-protected 2-amino-2-deoxy-d-glucose chloride was achieved under phase transfer catalytic conditions in a 0.15 M aqueous K₂CO₃/chloroform system using tetrabutylammonium bromide as the catalyst. On the contrary, glycosylation with the N-phthalimido-protected bromide donor under the same conditions was found to give predominantly 1,2-cis-glycoside product.

Keywords:

• Quercetin
• Glycosides
• 2-Amino-2-deoxy-d-glucose
• Stereoselective synthesis
• Phase transfer catalysis