Derivatives of N-amidinoproline and their Use in Conventional and Solid Phase Peptide Synthesis

S. V. Burov#, Yu. E. Moskalenko, M. V. Leko, M. Yu. Dorosh, and E. F. Panarin

#Phone/fax: (812) 323-36-07; e-mail:
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol’shoi pr. 31, St. Petersburg, 119004, Russia
Received: March 29, 2006;  in final form: May 3, 2006

Abstract: N-Amidinoproline, a hybrid structure modeling key features of the Arg-Pro sequence, was synthesized. The activation of carboxyl group of free N-amidinoproline was found to result in the formation of a cyclic side product, whose structure was confirmed by ESI MS, 1H NMR, and 13C NMR spectra. The preparation of N-(mesitylenesulfonylamidino)-L-proline using the mesitylenesulfonyl derivative of 2-methylisothiourea was demonstrated to be accompanied by partial racemization. The target product was synthesized by modification of N-amidinoproline by mesitylenesulfonyl chloride. The possibility of using N-amidinoproline in the N-terminal modification of a peptide chain was shown by the example of synthesis of an analogue of the 95–98 fragment of fibrinogen α chain.

Key words: N-amidinoproline, unnatural amino acids, synthetic polypeptides

Russian Journal of Bioorganic Chemistry 2006, 32 (6): 509-516