Co-ordination Compounds as Resolving Agents

IN the normal chemical resolution of amino-acids using organic bases, one optical antipode—corresponding to the less-soluble diastereoisomeric salt—can generally be obtained optically pure. The more soluble derivative remaining in the mother liquor is contaminated with a small amount of the less-soluble salt and is therefore always very difficult to obtain pure. The usual device of using both forms of the optically active base in turn is not feasible as only the natural occurring antipodes of the alkaloid bases (quinine, brucine, cinchonine, strychnine, etc.) are readily available.