In the dynamic field of pharmaceutical research and development, novel building blocks are continuously sought to create sophisticated therapeutic agents. One such crucial compound is Fmoc-4-Nitro-L-Phenylalanine, often referred to by its shorthand Fmoc-Phe(4-NO2)-OH. This specialized amino acid derivative plays a pivotal role in modern peptide synthesis, offering unique opportunities for chemists and biologists alike. Understanding its properties and applications is key to unlocking its potential in creating next-generation therapeutics.

Fmoc-4-Nitro-L-Phenylalanine is characterized by its chemical name, N-Fmoc-4-Nitro-L-Phenylalanine, and its CAS number, 95753-55-2. Its molecular formula, C24H20N2O6, and molecular weight of approximately 432.43 g/mol, provide essential information for chemical formulation and reaction planning. Typically appearing as a white to off-white powder, its purity is generally specified at 98% or higher via HPLC, ensuring reliability in precise scientific applications. Proper storage at 2-8°C in a tightly closed container is recommended to maintain its integrity.

The primary utility of Fmoc-4-Nitro-L-Phenylalanine lies in its ability to be incorporated into peptide chains during Fmoc solid-phase peptide synthesis. The presence of the nitro group on the phenylalanine side chain offers distinct advantages. It can be utilized as an intrinsic IR probe, allowing researchers to monitor peptide conformation and folding in real-time. Furthermore, it can act as a quencher in Förster Resonance Energy Transfer (FRET) pairs, facilitating the study of molecular interactions and conformational changes within peptides and proteins. This capability is invaluable for researchers working on understanding complex biological processes.

Beyond its utility as a probe, Fmoc-4-Nitro-L-Phenylalanine serves as a critical intermediate in the synthesis of more complex molecules. Notably, it is employed in the preparation of squaric acid derivatives that function as VLA-4 integrin antagonists. VLA-4 integrins are cell surface receptors involved in inflammatory responses and cell adhesion, making their antagonists promising targets for treating autoimmune and inflammatory diseases. By providing a modified phenylalanine residue, Fmoc-4-Nitro-L-Phenylalanine facilitates the precise construction of these potential therapeutic agents. Additionally, it finds application as an intermediate in the synthesis of analogs of kahalalide F, a naturally occurring compound with significant biological activity.

The demand for high-quality peptide synthesis reagents like Fmoc-4-Nitro-L-Phenylalanine continues to grow as research into peptide-based drugs and biochemical tools expands. Companies specializing in fine chemicals and custom synthesis, such as NINGBO INNO PHARMCHEM CO.,LTD., play a vital role in supplying these essential materials. Access to reliable sources of these advanced amino acid derivatives empowers scientific innovation, enabling breakthroughs in areas ranging from cancer therapy to the development of diagnostic imaging agents. The ongoing research into VLA-4 integrin antagonists and other peptide-based therapeutics underscores the importance of such specialized chemical intermediates in advancing human health.