L-4-Iodophenylalanine CAS 24250-85-9 high stereopurity unnatural amino acid derivative

L‑4‑Iodophenylalanine, also named H‑Phe(4‑I)‑OH, is a para-substituted unnatural aromatic amino acid derived from L‑phenylalanine. An iodine atom sits at the para position of the benzene ring, bringing unique heavy atom and electronic features not found in natural protein-building amino acids. The molecule strictly retains L stereochemistry and delivers steady optical rotation with little risk of racemization under recommended storage.

This chiral building block appears as fine crystalline powder. Its iodine substituent delivers distinct detection signals in mass spectrometry and X-ray crystallography. Many research groups introduce this monomer into synthetic peptide sequences to build traceable molecular probes. It acts as a foundational raw material for academic biochemical exploration and early-stage molecular fragment construction. Storing away from light at low temperature preserves structural integrity and extends usable shelf life.

This compound decomposes between 240–260 °C without a sharp melting point. It dissolves poorly in pure water while showing good solubility in dimethyl sulfoxide and dilute acidic solutions. Extended exposure to ambient light may trigger gradual deiodination and compromise chiral quality. The dry powder shows low hygroscopicity when kept under moderate humidity.

The heavy iodine substituent offers two key analytical strengths. It creates strong scattering signals for crystallographic structure determination and provides a unique mass signature for tracking labelled peptides inside complex biological mixtures. These characteristics set it apart from fluorinated or chlorinated phenylalanine analogues.

This unnatural amino acid supports controlled incorporation during solid phase peptide synthesis. Once integrated into peptide backbones, it enables site-specific modification and bioconjugation. It supports quantitative tracking in proteomics and helps researchers measure peptide binding toward target receptors. It also serves as a starting precursor for new bioactive molecules and custom molecular fragments.

Typical research directions cover protein structure analysis, radiolabel precursor preparation, and peptide probe fabrication for in vitro biological assays.

Carry out operations within a ventilated workspace and wear suitable protective gear for eyes and skin. Avoid inhaling fine powder dust. Keep the material separate from oxidising substances, which can accelerate iodine release. Seal containers tightly right after sampling. Do not store alongside strong bases. Dispose of residual material following local chemical waste regulations.