Amino-acids and peptides. Part XXVI. The use of 1-piperidyl esters in peptide synthesis: further studies

Abstract

Further examples of the use of 1-piperidyl esters for the synthesis of protected dipeptides have given good yields of pure product except when two valine residues were involved (in which case the reaction of the analogous p-nitrophenyl ester was also very slow), or when one residue was α-aminoisobutyric acid. The reactions of benzyloxy-carbonylamino-acid 1-piperidyl esters with the methyl esters of L-leucyl-L-leucylglycine, L-phenylalanyl-L-leucylglycine, and L-valyl-L-eucylglycine proceeded more slowly than with α-amino-esters but satisfactory yields were obtained except in one case, again involving valine.