N-Hydroxy Amides. III. Active Esters of Polystyrene-bound 1-Hydroxy-2-pyrrolidinone and Their Use in Peptide Synthesis
A polymer-bond cyclic N-hydroxy amide has been prepared by reaction of aminomethylated copoly(styrene-2percent divinylbenzene) with 1-hydroxy-5-oxo-3-pyrrolidinecarboxylic acid using dicyclohexylcarbodiimide (DCC) as a condensing agent.Several N-blocked α-amino acids have been loaded on this resin by use of DCC.The amino acid resin can be utilized for peptide synthesis.Repetitive usage of the resin in the form of esters and facile synthesis of a biologically active pentapeptide, Leu5-enkephalin, show the usefulness of the polymer-bound 1-hydroxy-2-pyrrolidinone.