Application Of N-benzoxycarbonyl-5-oxazolidinone In Dipeptide Synthesis

Peptide influence many important physiological functions in the organism,and play an important role in the life chemistry.Peptide chemistry,as one of the most active aera of organic chemistry,drove many attentions.The key issue is activation of carboxyl group for the formation of amide.Especially,to avoid racemization is the vital problem in peptide synthesis.N-benzoxycarbonyl-5-oxazolidinone was synthesized for peptides synthesis from C-terminal.The reagent N-benzoxycarbonyl-5-oxazolidinones were readily prepared by the reaction of corresponding N-benzoxycarbonyl amino acids and paraformaldehyde.The chirality of the amino acid is unchanged.This reagent can be regarded as an activated form of carboxyl of amino acid.We got their mono crystal structure.Because the oxygen atom of the carbonyl has a weak hydrogenbonding with the hydrogen in the N-benzoxycarbonyl-5-oxazolidinones,they are quite stable in atmosphere,and can be kept for a long time.Therefore,in this thesis,this method was applied to synthesize a variety of dipeptides,and high performance liquid chromatography was used to detect the degree of racemization.It was found that the racemization is under 2.2%and peptide yield is about 70～80%.The N-benzoxycarbonyl Aspartylphenylalanine methyl ester (N-benzoxycarbonyl Aspartame) was also synthesized without the protection of theβ-carboxyl of asparagine.And there is noβ-type side-product produced.The racemization is 2.0%and the yield is 55%.In conclusion,peptide synthesis from N-benzoxycarbonyl-5-oxazolidinone has the advantages of easy handling,cheap raw material,low racemation,and saving the step of coupling reagent.