abstract |
A process for the preparation of 4-amino-1-hydroxybutylidene-1,1-bisphosphonic acid or salts thereof which comprises: (a) reacting 4-aminobutyric acid with a mixture of phosphorous acid and PCl3 in the presence of methanesulfonic acid; and (b) recovering said 4-amino-1-hydroxybutylidene1,1-bisphosphonic acid or salts thereof. e |