Improved process for manufacture of 4-amino-hydroxybutylidene-1,1-bisphosphonic acid and its salts

摘要

Disclosed herein is a cost effective, high yielding, reproducible method for the manufacture of alendronic acid or its salt such as sodium alendronate from inexpensive and readily available pyrrolidone using phosphonating agents such as PCl 3 in the presence of acids such as sulphonic acids, sulphuric acid or phosphoric acid.