1. Peptide Chemistry Research Center, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran, Iran
2. Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
3. Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany