A simple preparation of N-phosphorylated lysine and arginine.

An improved specific synthesis of N-epsilon-phospholysine is described. Phosphorylation under basic conditions of the copper chelate of L-lysine with phosphorus oxychloride and subsequent removal of the copper ion affords N-epsilon-phospholysine as the sole phosphorylated product. Similar treatment of L-arginine yields N-omega-phosphoarginine as the sole product which is identical to that produced enzymatically.