Efficient synthesis of optically pure Nω-alkylated L-arginines

Abstract

A number of Nω-substituted L-arginines have been described to date, particularly with regard to nitric oxide synthase (NOS) modulators. Elaborate multistep syntheses and low yields limit the scope of preparing these modified L-arginines. We describe a synthetic methodology that delivers N ω-alkylated L-arginine derivatives from protected L-ornithine in a three-step sequence with excellent overall yields (81-90%) and in high purity. Analysis of the synthesized amino acids on a Crownpak Cr(+) column revealed no significant racemization, that is, >99.9% ee for all final compounds. © Georg Thieme Verlag Stuttgart.