New Method for Preparing Isofagomine and Its Derivatives

1 . A method for preparing isofagomine, its derivatives, or acid salts thereof, comprising:

protecting the anomeric hydroxyl group of D-(−)-arabinose with a protecting group to form a glycoside;

further protecting by converting said protected glycoside to an acetonide using a ketal or ketone;

converting said acetonide to an alkoxide and reacting with an alkylating agent to form an ether;

converting said ether to a diol having two protecting groups;

further protecting said diol using selective etherification to form a triprotected arabinose derivative;

converting said arabinose derivative to a triprotected xylose derivative using an activated system;

converting said xylose derivative to a triprotected nitrile using an activated system;

converting said nitrile using catalytic hydrogenation.

2 - 8 . (canceled)

9 . The method of claim 1 , wherein the protecting group is selected from benzyl, methoxybenzyl, chlorobenzyl, diphenylmethyl, methyl, ethyl, isopropyl or cyclohexylmethyl.

10 . The method of claim 1 , wherein the ketone or ketal is selected from acetone, 2-butanone, benzophenone, cyclohexanone, acetophenone, or their corresponding dialkylketals.

11 . The method of claim 1 , wherein the activated system is selected from p-toluenesulfonate, methanesulfonate, and trifluoromethanesulfonate

12 . A method for preparing isofagomine, its derivatives, or acid salts thereof, comprising:

protecting the anomeric hydroxyl group of D-(−)-arabinose with a protecting group to form a glycoside having the structure of compound A:

wherein the protecting group is selected from benzyl, methoxybenzyl, chlorobenzyl, diphenylmethyl, methyl, ethyl, isopropyl or cyclohexylmethyl;

further protecting by converting said protected glycoside to an acetonide using a ketal or ketone, wherein the ketone or ketal is selected from acetone, 2-butanone, benzophenone, cyclohexanone, acetophenone, or their corresponding dialkylketals, and wherein the acetonide has the structure of compound L:

converting said acetonide to an alkoxide and reacting with an alkylating agent to form an ether, wherein the ether has the structure of compound M:

converting said ether to a diol having two protecting groups, wherein the diol has the structure of compound N:

further protecting said diol using selective etherification to form a triprotected arabinose derivative, wherein the arabinose derivative has the structure of compound O:

converting said arabinose derivative to a triprotected xylose derivative through an intermediate comprising a leaving group selected from p-toluenesulfonate, methanesulfonate, and trifluoromethanesulfonate, and wherein the xylose derivative has the structure of compound Q:

converting said xylose derivative to a triprotected nitrile through an intermediate comprising a leaving group selected from p-toluenesulfonate, methanesulfonate, and trifluoromethanesulfonate, and wherein the nitrile has the structure of compound S:

and

converting said nitrile using catalytic hydrogenation.

13 . The method of claim 12 , wherein the protecting group is benzyl.

14 . The method of claim 12 , wherein the ketone or ketal is selected from acetone, 2,2-dimethoxypropane, or combinations thereof.

15 . The method of claim 12 , wherein the leaving group is trifluoromethanesulfonate.