H-Phe (3,5-DiF) -OH is a difluorophenylalanines in the L-configuration [L- (F2) Phe]. H-Phe (3,5-DiF) -OH can be incorporated into the thrombin receptor-tethered ligand peptide SFLLRNP to identify the phenyl hydrogens of the Phe-2 residue involved in the CH/π receptor interaction[1].