Patent ID: 8642761

Claim:
A method of synthesizing 3-amidrazono-phenylalanine derivatives of general formula (IIb) which are present as: L- or D-enantiomers, (E)- or (Z)-isomers, or (E/Z)-mixtures, and as free bases, or as salts thereof formed with acids 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, benzylaminocarbonyl 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 refluxing a nitrile of the general formula (III) 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, benzylaminocarbonyl 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, with an excess of hydrazine in alcoholic solution.