2,5-Dichloro-L-Phenylalanine, with CAS number 754971-91-0, is a non-natural, halogenated derivative of the essential amino acid L-phenylalanine. Its chemical structure features a phenylalanine backbone substituted with chlorine atoms at the 2- and 5-positions of the aromatic ring. This modification imparts distinct physicochemical properties compared to the parent amino acid. This compound serves as a crucial chiral building block in pharmaceutical research and development. Its primary application lies in the synthesis of complex bioactive molecules, particularly as a key intermediate for novel peptide-based drugs and enzyme inhibitors. The presence of the L-configuration ensures chirality, while the chlorine atoms can be leveraged to modulate lipophilicity, metabolic stability, and receptor binding affinity of the final drug candidate. As a specialty synthetic intermediate, it is not a bulk commodity but is utilized in medicinal chemistry for structure-activity relationship (SAR) studies and the production of targeted therapeutics. Handling requires standard laboratory precautions for amino acid derivatives.