Patent ID: 8450488
Filing Date: 2013-05-28
Classification: A61P,C07F

Abstract:
1. A process for the preparation of [1-hydroxy-2-(3-pyridinyl)ethylidene]bisphosphonic acid and hemi-pentahydrate monosodium salt thereof, the process comprising reacting aqueous solution of 3-pyridinyl acetic acid hydrochloride with phosphorus trichloride that is added dropwise at a temperature of 0-5° C., removing excess phosphorus trichloride, adding water to hydrolyze products of the reaction, isolating crystalline [1-hydroxy-2-(3-pyridinyl)ethylidene]bisphosphonic acid and suspending in water, adding soda lye, obtaining a precipitate, and filtering off, washing, and drying the precipitate to yield hemi-pentahydrate monosodium salt of [1-hydroxy-2-(3-pyridinyl)ethylidene]bisphosphonic acid.