Peptide Synthesis with Polymer Bound Active Ester. I. Rapid Synthesis of Peptides Using Polymer Bound 1-Phenyl-3-methyl-4-oximinopyrazole

Polymer bound 1-phenyl-3-methyl-4-oximinopyrazoles were prepared through a series of chemical modifications of Merrifield's resin (chloromethylpolystyrene- DVB-copolymer). Several polymer active esters of N-blocked amino acids were prepared from the polymer bound 1-phenyl-3-methyl-4-oximinopyrazoles. Polymer bound active esters were found to be highly reactive in N-acylation reaction. The resins were tested for the preparation of several dipeptides. The peptides were obtained in high yields within 10 minutes and the progress of the reactions could be easily followed up by the color change of the resin. The resulting peptides were characterized by NMR and other physical methods.