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.