METHOD FOR CLEANING 3-HYDROXYAMIDINOPHENYLALANINE DERIVATIVES BY THE PRECIPITATION AND RECRYSTALLISATION OF A SALT AND AN AROMATIC SULPHONIC ACID

The invention relates to a method for cleaning 3-hydroxyamidinophenylalanine derivatives comprising the steps: (a) addition of an aromatic sulphonic acid to a solution of an optionally contaminated 3-hydroxyamidinophenylalanine derivative in order to form a precipitate; (b) separation of the precipitate formed in step (a); and (c) recovery of the free 3-hydroxyamidinophenylalanine derivative from the precipitate. 3-hydroxyamidinophenylalanine derivatives can e.g. be used as urokinase inhibitors. The invention also relates to the use of highly pure 3-hydroxyamidinophenylalanine derivatives for producing 3-amidinophenylalanine derivatives. La invencion se refiere a un metodo para purificar derivados de 3-hidroxiamidinofenilalanina que comprende las etapas de: (a) adicionar un acido sulfonico aromatico a una solucion de un derivado de 3-hidroxiamidinofenilalanina eventualmente contaminado para formar un precipitado, (b) separar el precipitado que se forma en la etapa (a), y ( c ) recuperar del precipitado el derivado de 3-hidroxiamidinofenilalanina libre. Los derivados de 3-hidroxiamidinofenilalanina se pueden usar, por ejemplo, como inhibidores de la urocinasa. La presente invencion se refiere ademas al uso de derivados de 3- hidroxiamidinofenilalanina con alto grado de pureza para la produccion de derivados de 3-amidinofenilalanina.