D-Cyclopentylalanine is a non-proteinogenic amino acid in which the side chain is a cyclopentyl group attached to the alpha carbon, with the amino acid backbone bearing both an amino group and a carboxyl group. The molecule is specified as the D stereoisomer, and its hydrophobic, bulky cyclopentyl side chain provides a nonpolar surface that can influence peptide conformational preferences and side-chain packing. In synthetic and chemical biology workflows, it is used as a building block for preparing peptides and peptide analogues in which steric bulk and hydrophobic character are introduced for structure-activity studies, protein engineering experiments, and analytical method development.
CAT No: CP21402
D-Cyclopentylalanine is a D-configured amino acid bearing a cyclopentyl side chain that provides a hydrophobic, conformationally constrained alkyl surface for structure-function studies and peptide scaffold design. The molecule contains a stereogenic alpha carbon, a primary amino group, and a carboxylic acid functionality that can be selectively protected or activated for peptide coupling chemistry. Side-chain reactivity is dominated by the saturated cyclopentyl ring, enabling robust handling under standard amide-forming conditions while supporting hydrophobic packing in biomolecular recognition. As a chiral amino acid building block, D-Cyclopentylalanine serves as a stereochemically defined intermediate for protected amino acid derivatives and downstream peptide or peptidomimetic synthesis.
1. Peptide Synthesis
D-Cyclopentylalanine is applied in peptide synthesis as a D-amino acid building block for incorporating stereochemically defined hydrophobic residues into linear peptides and peptide fragments. The protected amino and activated carboxyl groups of D-Cyclopentylalanine derivatives can participate in standard peptide coupling strategies, while the cyclopentyl side chain supports stable amide formation without introducing additional reactive functionalities. D stereochemistry at the alpha center enables construction of D-residue-containing sequences for studying backbone stereochemical effects on folding, proteolytic stability, and receptor binding modes. Peptide building block preparation from D-Cyclopentylalanine can feed combinatorial library workflows and iterative SAR campaigns that require controlled incorporation of a nonpolar, conformationally restricted side chain.
2. Peptidomimetics And SAR Studies
D-Cyclopentylalanine is used in peptidomimetic and SAR studies where a D-configured alpha stereocenter and a cyclopentyl side chain together modulate hydrophobic contacts and local backbone geometry. The amino acid backbone can be converted into protected intermediates that enable selective functional group manipulation at the N- and C-termini, supporting fragment assembly into analogs with altered protease susceptibility or binding kinetics. Cyclopentylalanine's saturated ring can be retained through synthetic sequences to probe steric and hydrophobic contributions without introducing aromatic or heteroatom-driven electronic effects. D-Cyclopentylalanine-derived fragments can therefore serve as chiral inputs for molecular design cycles that compare stereochemical series and side-chain volume effects in structure-activity relationship investigations.
3. Chemical Biology Labeling
D-Cyclopentylalanine is suitable for chemical biology labeling strategies that require incorporation of a defined D-amino acid into peptide probes or protein-targeting constructs. The carboxylic acid and amino functionality enable conversion to N-protected amino acid derivatives and subsequent activation for conjugation handles, including attachment to linkers that carry fluorophores, affinity tags, or bioorthogonal motifs. Cyclopentyl side-chain hydrophobicity can influence probe localization and membrane association tendencies in labeling experiments, while D stereochemistry can help tune resistance to enzymatic degradation during imaging or pull-down workflows. D-Cyclopentylalanine can thus be employed as a stereochemically controlled residue for generating labeled biomolecule derivatives and for mapping binding interfaces using amino acid-level structural control.
4. Protected Amino Acid Chemistry
D-Cyclopentylalanine is used as a chiral precursor for protected amino acid chemistry, where selective protection of the amino group and controlled activation of the carboxyl group are required for reliable peptide coupling. The presence of a single stereocenter allows stereochemical integrity to be maintained through protection/deprotection sequences, making it a practical chiral building block for manufacturing peptide intermediates. Cyclopentylalanine's nonfunctionalized side chain reduces competing side reactions, supporting clean conversion to N-protected derivatives and facilitating downstream fragment coupling. Protected D-Cyclopentylalanine intermediates can feed fine chemical synthesis pipelines that require reproducible chiral amino acid inputs for automated peptide assembly and scale-up-compatible reaction planning.
5. Pharmaceutical Intermediate Preparation
D-Cyclopentylalanine is applied in pharmaceutical intermediate preparation for generating D-amino acid-containing fragments used in peptide-like drug candidates, constrained peptidomimetics, and stereochemically defined building blocks. The amino acid's bifunctional nature enables conversion into activated carboxylic acid derivatives or N-protected forms that can be incorporated into larger synthetic sequences through amide bond formation. D stereochemistry at the alpha carbon supports the construction of drug-relevant stereochemical patterns that can be carried through late-stage synthesis without requiring side-chain functional group transformations. D-Cyclopentylalanine-derived intermediates can therefore support process chemistry routes that prioritize chiral control, predictable coupling behavior, and scalable preparation of peptide analog components for specialty chemical production.
6. Industrial Biocatalysis Substrates
D-Cyclopentylalanine can serve as a substrate or chiral reference material in industrial biocatalysis and enzyme studies focused on amino acid recognition and stereoselective transformations. The cyclopentyl side chain provides a hydrophobic substrate profile that can be used to probe enzyme substrate specificity for D-amino acid-containing systems, while the amino acid's defined stereochemistry supports interpretation of stereochemical outcomes. Conversion to protected or activated derivatives may enable compatibility with enzymatic acylation, transpeptidation, or downstream chemical derivatization steps used in biocatalytic process development. D-Cyclopentylalanine-based intermediates can thus be employed in applied enzymology workflows that connect amino acid structure to catalytic selectivity and to the manufacture of stereodefined chiral building blocks.
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