4-tert-butyl-DL-Phenylalanine is a non-natural phenylalanine derivative bearing a tert-butyl substituent at the para position of the aromatic side chain, classifying it as an aryl-substituted amino acid with a benzyl-like hydrophobic side chain. The molecule contains a free amino group and a free carboxyl group on the α-carbon, and the "DL" designation indicates a racemic mixture of D and L stereoisomers at that center. As a substituted aromatic amino acid, it is used as a building block in peptide and amino acid derivative synthesis to introduce a bulky hydrophobic aryl side chain for structure-activity studies, conformational probing, and chemical biology labeling strategies where steric and hydrophobic effects are investigated.
CAT No: CP11303
4-tert-butyl-DL-Phenylalanine is a sterically hindered, non-natural phenylalanine derivative featuring a tert-butyl substituent on the aromatic ring and a DL stereochemical mixture at the alpha carbon. As a racemic amino acid building block, it is commonly used in peptide and peptidomimetic synthesis where aromatic hydrophobicity and steric bulk are leveraged to tune conformation, binding-site interactions, or protease susceptibility in structure-activity studies. Its free amino acid functionality makes it a practical starting material for downstream coupling to activated carboxylic acid derivatives or protected peptide fragments.
1. Peptidomimetic Building Blocks
4-tert-butyl-DL-Phenylalanine is used by medicinal chemistry and chemical biology groups to prepare peptidomimetic analogs that incorporate an aryl side chain with increased steric demand. The tert-butyl group on the phenyl ring provides a hydrophobic, bulky aromatic motif that can modulate local shape and side-chain packing in short peptides and constrained analogs. Because the material is supplied as a DL mixture, it is frequently selected for early-stage SAR screening, where researchers prioritize rapid access to analog libraries over stereodeconvolution at the building-block stage.
2. Structure-Activity Relationship Studies
4-tert-butyl-DL-Phenylalanine supports SAR workflows in which aromatic substitution patterns are systematically varied to probe how steric and electronic changes influence binding to receptors, enzymes, or protein-protein interfaces. Teams in small-molecule and peptide drug discovery use this building block to generate analog panels where the phenylalanine core is retained while the aryl substitution is tuned for different interaction geometries. The racemic nature is often used to maintain throughput during library synthesis, with stereochemical refinement performed later if a specific enantiomer proves relevant.
3. Peptide Library Synthesis
4-tert-butyl-DL-Phenylalanine is employed in custom peptide synthesis and peptide library construction as a non-natural amino acid component for introducing a bulky, hydrophobic aromatic residue. Researchers use it to diversify peptide sequences with altered side-chain sterics, which can affect aggregation propensity, conformational preferences, and overall physicochemical profiles of the resulting peptides. In practical library workflows, the DL format simplifies procurement and scale-up for parallel synthesis of multiple sequence variants.
4. Pharmaceutical Intermediate Development
4-tert-butyl-DL-Phenylalanine is also used as a specialty intermediate in the preparation of substituted phenylalanine-derived fragments for downstream medicinal chemistry programs. Process and development chemists rely on amino acid building blocks like this to access aryl-substituted motifs that are difficult to assemble late in synthesis, particularly when the aromatic substitution must be preserved through multiple transformations. The availability of a defined amino acid scaffold helps standardize intermediate quality for iterative analog production during lead optimization.
If you have any peptide synthesis requirement in mind, please do not hesitate to contact us at . We will endeavor to provide highly satisfying products and services.
Creative Peptides is a trusted CDMO partner specializing in high-quality peptide synthesis, conjugation, and manufacturing under strict cGMP compliance. With advanced technology platforms and a team of experienced scientists, we deliver tailored peptide solutions to support drug discovery, clinical development, and cosmetic innovation worldwide.
From custom peptide synthesis to complex peptide-drug conjugates, we provide flexible, end-to-end services designed to accelerate timelines and ensure regulatory excellence. Our commitment to quality, reliability, and innovation has made us a preferred partner across the pharmaceutical, biotechnology, and personal care industries.
Read More