Preparation of D-ornithine, D-citrulline, and D-arginine.

Neither n-ornithine nor n-citrulline has yet been described.’ A preparation of n-arginine by the action of arginase on racemic arginine was reported by Riesser in 1906 (2). For the ready preparation of these isomers, it was considered simplest to resolve DL-ornithine and to synthesize n-citrulline and n-arginine from n-ornithine by available procedures. The resolution of racemic ornithine was essentially that followed in the case of lysine (3).2