Semi-synthesis of neomangiferin from mangiferin

Neomangiferin, a natural xanthone derivative bearing both O- and C-glucosides, was isolated from the leaves of Gentiana asclepiadea L. and has shown potential anti-diabetic activity. We describe herein the first semi-synthesis of neomangiferin from the natural C-glucoside mangiferin and glucose. The developed synthesis presents a facile protection strategy using Jurd’s method to distinguish the different phenolic hydroxyl groups. Following this strategy, the regioselective protection of 1,3,6-hydroxyl groups was accomplished and neomangiferin was prepared by glycosylation under the phase-transfer catalysis conditions.