Synthesis and carbon 13 N.M.R. spectrum of the peptide fragment of myelin basic protein (human)

Abstract

The tridecapeptide Phe-Lys-Leu-Gly-Gly-Arg-Asp-Ser-Arg-Ser-Gly-Ser-Pro- OH, and its methyl ester derivative at the carboxyl terminal, -Pro-OMe,�were synthesized by the solution-phase method. The synthesis was accomplished by fragment condensation of a tetrapeptide, Boc-Phe- Lys(N8-Cbz)-Leu-Gly-OH, and a nonapeptide, H-Gly-Arg(NO2)-Asp(OBzl)- Ser(OBzl)-Arg(NO2)-Ser(OBzl)-Gly-Ser(OBzl)-Pro-OR (R = Me or Bzl), in the presence of dicyclohexylcarbodiimide and benzo-triazol-1-ol, to give the protected tridecapeptide. This compound, when OR = OBzl, was hydrogenated at room temperature, with Pd/C as catalyst, followed by treatment with boron tristrifluoro-acetate to remove all the protecting groups. When OR = OMe, the final product was the methyl ester of the tridecapeptide. The mixed anhydride method (REMA) was followed in the synthesis of the intermediates. 13C n.m.r. spectra of the tridecapeptide and of the peptide intermediates are discussed.