Novel process for preparing alendronic acid

摘要

A novel process for the preparation of alendronic acid is disclosed. The method comprises the steps of reacting a compound of formula I with H3PO3wherein R is an imido group and R1 is selected from the group consisting of chloro, bromo, iodo, fluoro, hydroxy, amino, -OR2 or -OC(O)R2, wherein R2 is C1-C12 alkyl, C1-C12 cycloalkyl or C1-C12 aryl; and then reacting the product of the first step with a deprotecting agent. Alendronic acid is then recovered. The method is safe, efficient and suitable for use on a large scale.