Patent ID: 8088921

Claim:
A method of synthesizing 3-amidino-phenylalanine derivatives of general formula (I) or salts thereof formed with acids, which are present as either L- or D-configurated isomers and wherein R 1 is selected from the group consisting of: (a) a group of formula wherein (i) p=1 and r=2 and R 2 is benzyloxycarbonyl, benyzlaminocarbonyl or 2-thienylhydrazinocarbonyl or (ii) p=2 and r=1 and R 2 is ethoxycarbonyl, 2-propyloxycarbonyl, 2-propylcarbonyl, 2-propylaminocarbonyl, methylaminocarbonyl or methyl; and (b) a group of formula wherein R 3 is selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, dimethylaminocarbonyl, acetyl, and propionyl, comprising the reduction of a compound of the general formula (IIa) present as L- or D-enantiomers, as (E)- or (Z)-isomers or (E/Z)-mixtures, and wherein R 1 is selected from the group consisting of: (a) a group of formula wherein (i) p=1 and r=2 and R 2 is benzyloxycarbonyl, benyzlaminocarbonyl or 2-thienylhydrazinocarbonyl or (ii) p=2 and r=1 and R 2 is ethoxycarbonyl, 2-propyloxycarbonyl, 2-propylcarbonyl, 2-propylaminocarbonyl, methylaminocarbonyl or methyl; and (b) a group of formula wherein R 3 is selected from the group consisting of methoxycarbonyk ethoxycarbonyl, benzyloxycarbonyl, dimethylaminocarbonyl, acetyl, and propionyl, in the presence of Pd/C in an alcoholic-aqueous solution with hydrogen or ammonium formiate.