Photochemical synthesis of amino acid and peptide oxo-esters
Amino acid and peptide oxo-esters have played an important role in peptide chemistry for many years. Various amino acid esters are commonly used as protecting groups for peptide synthesis in solution. Moreover, activated phenyl ester derivatives have been used for chemical ligation of peptides. However, the synthesis of amino acid and peptide oxo-esters is commonly performed under acidic or basic conditions. Under acidic conditions, acid-sensitive protecting groups may be cleaved, and under basic conditions racemization of amino acid esters is a common problem. Here we present the photochemical synthesis of amino acid and peptide oxo-esters. Based on the photochemical properties of N-acyl-7-nitroindolines, photoacylation is performed to produce amino acid and peptide esters under neutral conditions, thus minimizing racemization or epimerization. We demonstrated the usefulness of this method by installing ester protecting groups, by synthesizing fairly activated phenyl esters, fluorescent amino acid esters, and a fluorescent TAT peptide ester.^
Ornelas, Alfredo, "Photochemical synthesis of amino acid and peptide oxo-esters" (2013). ETD Collection for University of Texas, El Paso. AAI1546334.