| abstract |
The present invention provides a novel process for preparation of bisphosphonic acid derivatives or pharmaceutical acceptable salt thereof, by reacting carboxylic acid having structural formula (II) with phosphorous acid and a halophosphorous compound, wherein halophosphorous compound is selected from the group comprising of PCl<SUB>3</SUB>, PCl<SUB>5</SUB>, POCl<SUB>3</SUB>, PBr<SUB>3</SUB>, POBr<SUB>3</SUB>, and PBr<SUB>5</SUB> in presence of diphenyl ether. |