H-4-Nitro-D-Phe-OEt · HCl

H-4-Nitro-D-Phe-OEt · HCl is a D-configured phenylalanine ethyl ester hydrochloride bearing a para-nitro substituent on the aromatic ring. The molecule combines an amino functionality converted to an HCl salt with an ester-protected carboxyl group, establishing a protected-amino-acid ester framework that can be carried through peptide coupling sequences after appropriate base-mediated salt handling. The stereogenic center at the α-carbon is fixed in the D-configuration, enabling stereocontrolled incorporation into peptide analogs and chiral SAR libraries. The 4-nitro aromatic group provides a strongly electron-withdrawing handle that can participate in reduction, nucleophilic aromatic substitution after activation, and downstream derivatization to access diverse aromatic motifs.

1. Peptide Synthesis

H-4-Nitro-D-Phe-OEt · HCl is employed in peptide building-block workflows where a D-phenylalanine residue with a para-nitro aromatic side chain is required for stereochemical and electronic tuning. The amino group as an HCl salt and the carboxyl as an ethyl ester support standard peptide coupling compatibility after conversion to the free amine and activation of the ester into a coupling-ready form or after transesterification to the desired peptide synthesis format. The aromatic nitro substituent can withstand many coupling conditions and can be retained for later functional-group transformations, enabling construction of nitro-containing peptides and peptide fragments. The resulting D-amino-acid-containing sequences can be used to probe conformational effects and side-chain electronics in peptide science and synthetic methodology development.

2. Chiral Amino Acid Derivatization

H-4-Nitro-D-Phe-OEt · HCl serves as a chiral amino acid intermediate for derivatization strategies that leverage the fixed D-stereochemistry and the para-nitro functional group. The ethyl ester can be converted into alternative carboxyl activation states for further synthetic elaboration, while the nitro group provides a controlled entry point to reduced anilines, nitroso intermediates, or other aromatic transformations depending on the chosen downstream chemistry. The combination of stereogenic α-carbon and modifiable aromatic substituent enables preparation of enantiopure derivatives for chiral synthesis campaigns and structure-guided molecular design. Downstream products can include nitro-to-amino converted analogs for additional coupling handles, supporting iterative amino acid modification and fine chemical synthesis.

3. Peptidomimetics And SAR Studies

H-4-Nitro-D-Phe-OEt · HCl is suitable for peptidomimetic and SAR-focused synthesis where a D-phenylalanine scaffold with an electron-withdrawing nitro side chain helps modulate binding interactions and metabolic stability proxies. The protected amino acid ester form supports incorporation into constrained analogs by enabling controlled conversion into peptide-like fragments and subsequent coupling to other chiral building blocks. The para-nitro group can be retained to study electronic effects or transformed into alternative aromatic functionalities to map structure-activity relationships across a library of analogs. The stereochemical integrity of the D-center supports consistent interpretation of chirality-dependent trends in molecular recognition studies, feeding back into medicinal chemistry design cycles.

4. Chemical Biology Labeling

H-4-Nitro-D-Phe-OEt · HCl can be used in chemical biology workflows that require aromatic functional handles for conjugation or probe development. The nitro group functions as a transformable aromatic moiety that can be converted into amine-bearing derivatives, enabling subsequent attachment to linkers, fluorophores, affinity tags, or immobilization surfaces through amide or urea-forming chemistries after appropriate intermediate preparation. The D-configuration can help tune protease susceptibility and incorporation behavior in peptide-based probes, supporting experiments that compare stereochemical variants. The amino acid ester framework also supports downstream conversion into amide-linked conjugates or peptide conjugation intermediates for biomolecule modification campaigns.

5. Pharmaceutical Intermediate Preparation

H-4-Nitro-D-Phe-OEt · HCl is applicable to pharmaceutical intermediate preparation where chiral, functionalized amino acid derivatives are required as inputs to peptide-based or peptidomimetic manufacturing routes. The hydrochloride salt form aids handling of the amine functionality in controlled synthetic sequences, while the ethyl ester provides a defined carboxyl protection state that can be advanced to coupling-ready derivatives or converted into alternative activated forms as process steps dictate. The para-nitro aromatic substituent offers a stable functional group during intermediate stages and a later transformation opportunity to reach alternative aromatic substitution patterns used in medicinal chemistry programs. Industrial route design can therefore treat the compound as a stereodefined amino acid ester intermediate that supports scalable synthesis of downstream chiral building blocks and functional aromatic variants.

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