Efficient synthesis of N alpha-acetylarginine methylamide.

A simple preparation of Ac-Arg-(p-TosH or HCl)-NHMe is described. The NG-protonated Z-Arg was coupled with methylamine by the mixed anhydride method. Z-Arg-NHMe was purified as a NG-p-toluene sulfonate salt by crystallization from water. After removal of the Z group by catalytic hydrogenation and acetylation Ac-Arg(p-TosH)-NHMe was obtained. Ac-Arg(HCl)-NHMe was prepared by chromatography of the NG-TosH derivative on Dowex 44 (in Cl- form).