Phe(5-Cl-2-CF2H) is a modified phenylalanine derivative where the phenyl ring is substituted with a chlorine (Cl) atom at the 5-position and a difluoromethyl group (CF2H) at the 2-position. This modification introduces both electron-withdrawing effects and increased hydrophobicity to the phenylalanine residue. Such derivatives are used in peptide synthesis to alter the chemical and physical properties of peptides, potentially enhancing their stability, bioavailability, or binding affinity in biological applications. This specific substitution pattern can be useful in fine-tuning the activity and selectivity of peptide-based drugs or research compounds.