Protected amino acid active esters incorporating the 4-picolyl basic solubilizing group

Abstract

The 4-picolyl ester of 4-hydroxy-3-nitrophenylacetic acid has been prepared from an active polyester intermediate, and used as the precursor of a series of protected amino acid active esters. Thesecompounds were satisfactory coupling components in peptide syntheses. Purification of the protected peptides by acid washing was facilitated by the presence of the basic 4-picolyl moiety.