We have developed a microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanoparticles in water
previously. It is an organic solvent-free, environmentally friendly method for peptide synthesis. In this study, we have
investigated the racemization of cysteine during an aqueous based coupling reaction with MW irradiation. Under our
MW-assisted protocol using WSCI and DMTMM, the coupling reaction can be performed with low levels of racemization
of cysteine. We also demonstrated the synthesis of the nonapeptide oxytocin analogue, Cys(Acm)-Tyr-Ile-Gln-Asn-
Cys(Acm)-Pro-Leu-Gly-NH2 using our water based MW-assisted protocol with Fmoc-amino acid nanoparticles.