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International Journal of Peptides
Volume 2011 (2011), Article ID 854952, 10 pages
Research Article

Applications of Propargyl Esters of Amino Acids in Solution-Phase Peptide Synthesis

Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India

Received 27 January 2011; Accepted 12 April 2011

Academic Editor: Michal Lebl

Copyright © 2011 Ramesh Ramapanicker et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Propargyl esters are employed as effective protecting groups for the carboxyl group during solution-phase peptide synthesis. The propargyl ester groups can be introduced onto free amino acids by treating them with propargyl alcohol saturated with HCl. The reaction between propargyl groups and tetrathiomolybdate is exploited to deblock the propargyl esters. The removal of the propargyl group with the neutral reagent tetrathiomolybdate ensures that most of the other protecting groups used in peptide synthesis are untouched. Both acid labile and base labile protecting groups can be removed in the presence of a propargyl ester. Amino acids protected as propargyl esters are employed to synthesize di- to tetrapeptides in solution-phase demonstrating the possible synthetic utilities of the methodology. The methodology described here could be a valuable addition to currently available strategies for peptide synthesis.