4-Nitro-DL-Phenylalanine is a DL (racemic) phenylalanine derivative bearing a para-nitro substituent on the aromatic ring, classifying it as a substituted aromatic amino acid with an aniline-like electron-withdrawing functionality. The molecule contains both an amino group and a carboxyl group and features the stereochemical descriptor "DL" to indicate an equimolar mixture of enantiomers at the α-carbon, while the side chain retains the benzyl framework substituted by a nitro group that can participate in hydrogen-bonding and redox-active behavior under appropriate conditions. In peptide and amino acid chemistry workflows, this substituted amino acid is used as a building block for preparing analog peptides and for structure-activity or labeling studies where the nitro functionality provides a distinct chemical handle for analytical detection and downstream derivatization.
CAT No: CP16103
4-Nitro-DL-Phenylalanine is a nitro-substituted phenylalanine derivative supplied as a DL mixture, providing both D- and L- stereoisomers for structure-activity and stereochemical studies. The aromatic side chain bearing a para-nitro group makes it a useful aromatic, electron-withdrawing amino acid building block for peptide and peptidomimetic research, as well as for analytical method development where a defined nitroaryl motif is required. Its free amino acid functionality supports incorporation into synthetic sequences and preparation of standards for LC-MS and related characterization workflows.
1. Peptidomimetic Building Block
4-Nitro-DL-Phenylalanine is used as an amino acid building block in peptide and peptidomimetic synthesis to introduce a para-nitrobenzyl side-chain motif that can influence conformation, electronics, and aromatic interactions in the resulting sequence. Research groups developing structure-activity relationship (SAR) libraries frequently select this nitroaryl amino acid to probe how electron-withdrawing aromatic substitution affects binding or stability in non-clinical chemical biology assays. Because the product is supplied as a DL mixture, it is also commonly used in exploratory workflows where stereochemical effects are assessed by comparing outcomes from D- versus L-enriched analogs or by later stereochemical resolution of the active series.
2. Chemical Biology Probe Development
4-Nitro-DL-Phenylalanine is applied in chemical biology and molecular probe construction when a nitroaryl functionality is needed as a defined aromatic handle within a peptide scaffold. Investigators incorporate the amino acid into labeled or functionalized peptide probes to create sequence-defined reagents for studying aromatic recognition, local microenvironment effects, or probe-target interaction patterns in assay formats that rely on synthetic control of side-chain identity. The para-nitro group provides a chemically distinct aromatic signature that can be leveraged for downstream analytical readouts and for designing probe panels where side-chain electronics are systematically varied.
3. Analytical Standards For LC-MS
4-Nitro-DL-Phenylalanine is widely used as an analytical standard and reference material for validating LC-MS workflows that monitor nitroaryl amino acid motifs and related synthetic intermediates. Laboratories performing method development for amino acid profiling, impurity tracking, or peptide hydrolysate analysis use the defined nitro-substituted phenylalanine to confirm retention behavior and mass spectral assignment for compounds containing the para-nitrobenzyl side chain. The DL composition is particularly useful when the analytical goal is to track total compound signal independent of stereochemistry, or when stereochemical differentiation is not required for the method's intended use.
4. Pharmaceutical Intermediate Research
4-Nitro-DL-Phenylalanine serves as a practical intermediate building block in pharmaceutical intermediate development and specialty chemical manufacturing where a nitro-substituted phenylalanine motif is required for further derivatization. Process and R&D chemists incorporate this amino acid into downstream synthetic sequences to generate nitroaryl-containing intermediates used for medicinal chemistry exploration, including analog generation for SAR studies. The presence of both D- and L- stereoisomers supports early-stage route scouting and library synthesis, with stereochemical refinement typically addressed later when a specific stereochemical outcome becomes relevant to the target series.
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