Synthesis of [guanido-C-13]-gamma-hydroxyarginine

Abstract

This report describes an efficient method of synthesizing [guanido-C-13]-gamma-hydroxyarginine HCl salt. Iodolactonization of N-Boc-protected allylglycine mainly provided the cis iodo compound 2. This was converted to an amine through azide 4. The amine 5 was reacted with N-Boc-protected [C-13)thiourea to afford N-Boc-protected [C-13]guanidine 6, which underwent base catalyzed ring opening. Removal of the N-Boc group afforded [guanido-C-13]-gamma-hydroxyarginine HCl salt 7 giving a 30% overall yield of the final product from N-Boc protected allylglycine 1 in five steps.