the present invention describes a method for the synthesis of enantiomerically pure 3 - amidinophenylalanine derivatives , which are used as pharmaceutically effective urokinase inhibitors , by starting from 3 - cyanophenylalanine derivatives . the methods of manufacture comprising only one synthesis step lead to new intermediates , namely 3 - hydroxyamidino - and 3 - amidrazonophenylalanine derivatives . these intermediates or their acetyl derivatives can be reduced into the desired 3 - amidino - phenylalanine derivatives under gentle conditions , ethanol / water , room temperature , normal pressure or also h 2 , pd / c , acoh or hcl / ethanol , 1 - 3 bar ) in excellent yields and in an enantiomeric excess of up to 99 . 9 %.