Process for preparing and isolating 9-deoxo-9(z)-hydroxyiminoerythromycin a

Abstract From the Canadian patent

The present invention relates to a process for preparing 9-deoxo- 9(Z)-hydroxyiminoerythromycin A corresponding to formula (I) below: (see formula I) , from 9-deoxo-9(E)-hydroxyiminoerythromycin A by reaction with a base in water or , in a mixture of water/solvent of dialkyl ketone type capable of forming a crystallizable solvate with the desired 9(Z)-oxime; acidification of the reaction , mixture to a pH of between 9 and 11; addition to the said mixture of an organic , solvent; optionally concentration under vacuum of the resulting organic phase; and , isolation of the desired 9(Z)-erythromycin oxime.