S‐(2‐Pyrimidinyl)‐ and S‐(2‐(4,6‐Dimethylpyrimidinyl))‐1,1,3,3‐tetramethylthiouronium Hexafluorophosphates: Novel Reagents for in situ Peptide Coupling.

Abstract Two new reagents for in situ peptide coupling based on the 2-mercaptopyrimidine core have been developed. The readily prepared thiouronium salts were found to promote both peptide and segment coupling efficiently with low racemization/epimerization levels.