Fmoc-3,5-Dimethy-L-Phenylalanine is an Fmoc-protected, modified proteinogenic amino acid derivative in which the phenylalanine side chain bears two methyl substituents at the 3 and 5 positions. The molecule contains a free carboxyl group and an Fmoc carbamate on the amino functionality, with the stereocenter indicated as L at the alpha-carbon and a hydrophobic, sterically substituted benzyl side chain that can influence peptide microenvironment and packing. In peptide chemistry and chemical biology workflows, it is used as a building block for stepwise incorporation into peptide chains via protected-amino-acid chemistry, enabling structure-activity and conformational studies that probe how ring substitution patterns affect peptide properties.
CAT No: CP14306
Fmoc-3,5-Dimethy-L-Phenylalanine is an Fmoc-protected L-phenylalanine derivative bearing a chiral benzylic stereocenter and a sterically enriched aromatic side chain substituted at the 3,5-positions with two methyl groups. The molecule contains the Fmoc carbamate on the amino functionality and a free carboxyl group (or carboxylate-ready acid form depending on handling), enabling controlled peptide coupling chemistry while minimizing side reactions during solid-phase or solution-phase synthesis. The 3,5-dimethyl substitution increases hydrophobic surface area and can modulate aromatic packing, while the Fmoc group provides orthogonal protection that can be removed under standard base-mediated conditions without disturbing the substituted phenyl ring. As a chiral, protected amino acid building block, it functions as a downstream intermediate for peptide analog construction, side-chain functional tuning, and structure-driven design of hydrophobic or sterically constrained motifs.
1. Peptide Synthesis
Fmoc-3,5-Dimethy-L-Phenylalanine supports peptide building block preparation for both solid-phase and solution-phase peptide coupling workflows. The Fmoc-protected amine and carboxylic acid functionality enable standard amide bond formation strategies while the 3,5-dimethylphenyl side chain remains stable under typical coupling and deprotection conditions. Steric shielding from the ortho-adjacent methyl groups can influence coupling microenvironment and subsequent conformational preferences in the growing peptide chain. Incorporation of this chiral residue into peptides can be applied to generate hydrophobic, sterically tuned peptide sequences for research-grade scaffold development and synthetic library assembly.
2. Peptidomimetics
Fmoc-3,5-Dimethy-L-Phenylalanine serves as a chiral aromatic residue for peptidomimetic construction where side-chain sterics and hydrophobicity are used to control binding-site complementarity. The substituted phenyl ring at the 3,5-positions can participate in van der Waals contacts and aromatic shape complementarity while the Fmoc-protected backbone enables stepwise assembly into constrained analogs. The amino acid's stereochemical integrity supports incorporation into defined peptide-like frameworks that can later be diversified through side-chain derivatization or backbone modification. Downstream use can include generation of peptide analogs for molecular recognition studies and fragment-to-lead optimization campaigns that rely on reproducible stereochemistry.
3. Chemical Biology
Fmoc-3,5-Dimethy-L-Phenylalanine can be employed in chemical biology workflows that require incorporation of a controlled hydrophobic aromatic motif into protein or peptide probes. The protected amino acid form allows installation of the residue into tagged peptides used for affinity capture, imaging probe development, or substrate-mimicking constructs, while the Fmoc group supports orthogonal handling during synthesis. The 3,5-dimethylphenyl side chain can modulate membrane association tendencies and local packing, which may affect probe behavior in biochemical assays without introducing additional reactive handles. The resulting labeled or scaffolded peptides can function as biochemical research intermediates for studying molecular interactions, enzyme recognition patterns, or binding-site tolerance to steric bulk.
4. Protein Engineering
Fmoc-3,5-Dimethy-L-Phenylalanine enables residue-level design in protein engineering contexts that rely on synthetic peptide segments or engineered constructs. The L-configuration at the benzylic center preserves stereochemical fidelity for incorporation into peptide regions that model or replace native hydrophobic residues. The Fmoc-protected amine and carboxyl group facilitate consistent fragment assembly, while the 3,5-dimethyl substitution provides a sterically constrained aromatic side chain that can be used to probe packing effects, helix stability, or interface complementarity in designed sequences. Downstream derivatives prepared from this residue can include synthetic protein fragments, binding domains, or engineered scaffolds used in structure-guided protein design and interaction mapping.
5. Process Chemistry Intermediate
Fmoc-3,5-Dimethy-L-Phenylalanine is suitable for process chemistry intermediate preparation where protected amino acid reagents are manufactured and then converted into peptide building blocks under controlled conditions. The Fmoc carbamate provides a stable protection strategy during storage and handling, while the chiral amino acid framework supports predictable coupling behavior in downstream manufacturing steps. The substituted aromatic side chain is chemically robust and can withstand typical protection-deprotection and coupling reagent exposure used in fine chemical synthesis. The compound can therefore be used as a defined chiral input for producing peptide intermediates at scale, including specialty chemical production of hydrophobic amino acid residues for research and industrial peptide manufacturing.
6. Side-Chain Functionalization
Fmoc-3,5-Dimethy-L-Phenylalanine supports side-chain functionalization strategies that leverage the substituted aromatic ring for subsequent derivatization or scaffold diversification. The 3,5-dimethylphenyl group provides steric modulation that can influence electrophilic aromatic substitution, directed functionalization, or oxidative transformations performed after peptide assembly or on liberated amino acid-derived intermediates. The Fmoc-protected backbone enables isolation of the residue during synthetic planning, allowing selective deprotection and re-protection sequences when orthogonal protection schemes are required. Downstream formation of modified aromatic derivatives can be applied to generate structure-activity relationship libraries, analytical standards, or functionalized peptide analogs used in applied synthetic organic chemistry and biochemical research intermediate development.
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