Abstract
When N-methylmorpholine salt of Boc-Ile was coupled with HCl·Pro-Pro-resin suspended in methylenechloride by dicyclohexylcarbodiimide, diketopiperazine formation of the dipeptide-resin was suppressed almost completely and the isoleucine residue in the synthesized Boc-Ile-Pro-Pro-resin was not racemized. Generalization of this coupling procedure in a schedule for solid phase peptide synthesis is suggested.
