Metal-free functionalization of tyrosine residues in short peptides and study of the morphological alterations†
Abstract
An efficient functionalization of tyrosine residues in phenolic regions is achieved under metal-free conditions. The strategy involves the conversion of a tyrosine residue to 4-amino phenylalanine or 4-amino-3-methoxy phenylalanine in short peptides through a controlled oxidative dearomatization. This transformation is achieved in one pot with good yields and excellent regioselectivity. Consequently, the self-assembly of the peptide compounds has been studied at the nanoscopic level before and after functionalization. The results suggest that the peptide derivatives comprising amide groups promote intermolecular H-bonding interactions and the difference in –OH and –NH2 functional groups is found to be responsible for the morphological changes. Morphological transitions from 1D nanowires to 2D nanosheets were observed during functional group modification.