Solid phase synthesis of a GHRP analog containing C-terminal thioamide group

[Lyst6]GHRP, the C-terminally thionated analog of the highly potent growth hormone releasing hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 was prepared by using solid support. The success of the synthesis showed that Lawesson's reagent can be used for selective thionation of an amide group not only in solution but also on the surface of a resin. The C-terminal thioamide group proved to be stable under the conditions of the solid phase synthesis.