Patent ID: 8779191

Claim:
A method of preparing a lysine-amphetamine compound, comprising admixing an amphetamine compound of Formula I with a lysine compound of Formula II to provide a lysine-amphetamine compound of Formula III, wherein Formula I is represented by: or a salt thereof; Formula II is represented by: wherein Z is and R 3 is hydrogen; and Formula III is represented by: and crystallizing said lysine-amphetamine compound of Formula III from a mixture comprising (i) at least one of a C 1 -C 4 aliphatic alcohol, C 1 -C 4 aliphatic carboxylic acid, aliphatic tertiary amine, or water, and (ii) (C 1 -C 4 alkyl)—CO 2 —(C 1 -C 4 alkyl), to provide a purified lysine-amphetamine compound of Formula III.