L-Cyclopropylalanine is a naturally occurring amino acid in the alanine family, featuring an α-amino and α-carboxyl group attached to a cyclopropyl side chain that replaces the methyl group of alanine. The molecule is present as the L-stereoisomer as indicated by its name, and its side chain provides a compact, conformationally constrained hydrophobic functionality that can influence peptide backbone-side chain packing. As a free amino acid, it is used as a defined building block for peptide synthesis and for structure-activity or biophysical studies where incorporation of a cyclopropyl-bearing residue helps probe effects of steric shape and side-chain rigidity.
CAT No: CP21301
CAS No:102735-53-5
Synonyms/Alias:L-Cyclopropylalanine;102735-53-5;(s)-2-amino-3-cyclopropylpropanoicacid;L-3-cyclopropylalanine;(S)-2-Amino-3-cyclopropyl-propionicacid;3-cyclopropyl-L-alanine;l-beta-cyclopropylalanine;(2S)-2-amino-3-cyclopropylpropanoicacid;h-beta-cyclopropyl-l-ala-oh;D-3-(Cyclopropyl)alanine;3-cyclopropylalanine;h-ala(cyclopropyl)-oh;l-ala(3-cyclopropyl);AC1OCVPY;PubChem17439;h-beta-cyclopropyl-ala-oh;(l)-beta-cyclopropylalanine;SCHEMBL75669;CTK7D1079;MolPort-000-000-931;XGUXJMWPVJQIHI-YFKPBYRVSA-N;ZINC405158;ACT00047;SBB065934;AKOS012011074
L-Cyclopropylalanine is a naturally occurring L-amino acid bearing a cyclopropyl side chain attached to the stereogenic alpha carbon, providing a compact, conformationally constrained hydrophobic moiety. The molecule contains a primary amino group and a carboxylic acid functionality, which together support standard amino acid coupling chemistry and salt formation behavior across a wide pH range. The cyclopropyl ring can participate in stereoelectronic and conformational effects that influence peptide backbone/side-chain interactions, while the aliphatic character supports downstream derivatization to nonpolar analogs. As a chiral amino acid intermediate, L-cyclopropylalanine can be incorporated directly into peptide synthesis workflows or converted into protected derivatives to support controlled N- and C-terminal chemistry.
1. Peptide Synthesis
L-Cyclopropylalanine is used in peptide synthesis as an L-configured amino acid building block for assembling cyclopropyl-containing peptide sequences and peptidomimetic scaffolds. The alpha-amino and alpha-carboxyl groups enable amide bond formation through standard peptide coupling strategies, while the cyclopropyl side chain provides a hydrophobic residue that can modulate local conformations and side-chain packing. Protected amino acid derivatives of L-cyclopropylalanine can be selected to control N-terminal reactivity and to maintain compatibility with iterative coupling and deprotection cycles. The resulting cyclopropyl-substituted peptides serve as research materials for studying sequence-dependent structure and for generating analog libraries for synthetic methodology development.
2. Chiral Amino Acid Derivatization
L-Cyclopropylalanine is applied in chiral synthesis and amino acid derivatization workflows where preservation of the L-stereocenter is required for downstream stereochemical integrity. The primary amine and carboxylic acid can be transformed into activated intermediates, N-protected amino acid derivatives, or ester forms to tune solubility and reactivity in synthetic organic chemistry. Cyclopropyl side-chain incorporation can be leveraged to access constrained analogs that may improve conformational definition in SAR studies or molecular design efforts. Downstream products include functionalized amino acid intermediates suitable for further side-chain modification, fragment elaboration, and chiral building block preparation.
3. SAR Studies And Molecular Design
L-Cyclopropylalanine is utilized in drug discovery research and molecular design programs as a noncanonical amino acid to probe structure-activity relationships through side-chain sterics and conformational effects. The cyclopropyl group acts as a compact hydrophobic substituent that can influence binding pocket fit and local dynamics when incorporated into peptides or peptide-like ligands. The amino acid backbone supports systematic substitution at defined positions, enabling comparative synthesis of analog series where only the stereochemically defined residue changes. The compound thus functions as a practical chiral input for generating structure-defined libraries and for supporting iterative design cycles in medicinal chemistry.
4. Peptidomimetics And Unnatural Residues
L-Cyclopropylalanine is suitable for peptidomimetic construction where cyclopropyl-containing residues are introduced to emulate hydrophobic contact patterns while maintaining a defined stereochemical center. The amino acid framework can be converted into protected intermediates that participate in coupling to form amide-linked scaffolds, including constrained or backbone-modified analogs. The cyclopropyl side chain can be retained as a stable hydrophobic motif during synthesis of peptide analogs intended for receptor or enzyme interaction studies. The resulting peptidomimetic building blocks support downstream derivatization into non-natural residue-containing constructs for biochemical research and synthetic methodology exploration.
5. Analytical Research Standards
L-Cyclopropylalanine is used in analytical research as a chiral reference material and derivatization target for amino acid profiling and method validation. The presence of both an amine and a carboxylic acid allows formation of detectable derivatives for chromatographic or spectrometric workflows, and the cyclopropyl side chain provides a distinct retention and fragmentation signature relative to common aliphatic amino acids. Protected forms can also be prepared to match the chemical environment used in peptide hydrolysis or amino acid release studies. The compound thereby supports accurate identification and quantification of cyclopropyl-containing species in research-grade analytical applications and intermediate characterization.
6. Pharmaceutical Intermediate Preparation
L-Cyclopropylalanine is applied in pharmaceutical intermediate preparation and process chemistry as a defined chiral amino acid feedstock for manufacturing-oriented synthesis of cyclopropyl-substituted intermediates. The stereochemically defined alpha carbon and functional amino acid groups enable conversion into N-protected and C-activated derivatives used for controlled coupling steps in multi-stage syntheses. The cyclopropyl side chain can be carried through to downstream intermediates that serve as building blocks for peptide-like candidates or other nitrogen-containing fine chemicals. The compound's role as a chiral starting material supports scalable route design where stereochemical fidelity and functional-group compatibility are central to industrial chemical manufacturing workflows.
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