US Patent 7129355 Process for preparing kifunensine intermediate and kifunensine therefrom

A novel method for the preparation of a compound of formula (I) from an N—protected-D-mannosamine. A compound of formula (I) is a useful intermediate for the preparation of kiftnensine, a potent and selective mannosidase inhibitor. The method includes protecting the hydroxyl group at the C-6 position of an N—protected-D-mannosamine, to give a 6—O—protected—N—protected-D-mannosamine; reducing the C-1 anomeric carbon atom of the 6—O—protected—N—protected-D-mannosamine to give a 6—O—protected—N—protected-D-mannitol; protecting the four hydroxyl groups of the 6—O—protected—N—protected-D-mannitol; and removing the nitrogen atom protecting group and optionally removing the C-6 oxygen atom protecting group to give the compound of formula (I):