Patent ID: 8575385

Claim:
A process of making 4-(bis-(2-hydroxyethyl)amino)-L-phenylalanine of the formula wherein R1 is H or a lower straight or branched chain alkyl of 1 to 6 carbons, comprising the steps of; (a) reacting a predetermined amount of ethylene oxide, with 4-amino-L-phenylalanine of the formula wherein R1 is H or a lower straight or branched chain alkyl of 1 to 6 carbons, to obtain 4-(bis-(2-hydroxyethyl)amino)-L-phenylalanine of the formula wherein R1 is H or a lower straight or branched chain alkyl of 1 to 6 carbons; and (b) purifying the 4-(bis-(2-hydroxyethyl)amino)-L-phenylalanine obtained in step (a) with an aqueous organic solvent mixture.