Novel linker for the solid-phase synthesis of guanidines

Abstract

A novel linker for the generation of alkyl-, acyl- and arylguanidines as an attachment point in solid phase synthesis has been developed. Introduction of a suitably functionalized thiourea to Wang resin via a carbamate linkage, followed by displacement of sulfur with a 1° or 2° amine affords resin bound guanidines suitably protected for further manipulation. Activation of the thiourea with Mukaiyama's reagent allows for the generation of arylguanidines. Mild acid treatment effects deprotection and liberation from the resin to afford guanidines in good yield and high purity.