Azetidine-3-carboxylic acid is a cyclic, non-proteinogenic amino acid featuring an azetidine ring that positions the carboxyl group at the 3-position relative to the ring nitrogen, forming a constrained amino acid scaffold. The molecule contains a ring nitrogen and a carboxylic acid functional group, with the side-chain functionality expressed through the azetidine ring rather than a conventional acyclic side chain, which can influence conformational preference in peptide-like structures. In peptide chemistry and chemical biology, it is used as a building block to introduce a rigid azetidine-containing residue for structure-activity studies, backbone constraint design, and the preparation of modified amino acid or peptide analogues for analytical method development and molecular labeling workflows.
CAT No: CP20401
CAS No:36476-78-5
Synonyms/Alias:Azetidine-3-carboxylicacid;3-Azetidinecarboxylicacid;36476-78-5;3-azetanecarboxylicacid;3-Carboxyazetidine;h-aze(3)-oh;CaswellNo.063C;CHA-811;Azetane-3-carboxylicacid;l-azetidine-3-carboxylicacid;CHEMBL310435;MFCD00191763;EPAPesticideChemicalCode128830;BRN0385928;F2158-1519;PubChem10160;ACMC-209ims;AC1L3PP4;AC1Q74PT;SCHEMBL42967;KSC222O6J;391131_ALDRICH;AMOT0006;UNII-56Y8G819O3;CTK1C2764
Azetidine-3-carboxylic acid is a small, cyclic, non-proteinogenic amino acid building block featuring a strained four-membered azetidine ring and a carboxylic acid at the 3-position. Its rigid ring scaffold makes it a useful structural element in peptidomimetic and medicinal chemistry programs where conformational control and backbone constraint are valued. As a free amino acid, it is commonly handled as a synthetic intermediate for preparing protected derivatives and coupling-ready forms used in downstream peptide and analog construction.
1. Peptidomimetic Building Blocks
Azetidine-3-carboxylic acid is used by medicinal chemists and peptide-analog developers to introduce an azetidine-constrained residue into peptidomimetics and constrained amino acid series. The ring strain and defined geometry can help shape local backbone conformation in structure-activity relationship (SAR) studies, where analog libraries are synthesized to probe how stereochemistry and scaffold rigidity influence properties such as target engagement and overall molecular shape. In practice, researchers typically convert the free acid into coupling-compatible derivatives before assembling short peptides, peptidomimetic oligomers, or side-chain-modified analogs for screening and characterization.
2. Peptide and Analog Synthesis
Azetidine-3-carboxylic acid serves as a direct precursor for preparing protected azetidine-containing amino acid derivatives used in both solution-phase and solid-phase peptide synthesis workflows. Peptide chemistry groups incorporate this scaffold to generate non-natural peptide segments, backbone-constrained analogs, and SAR-focused libraries where the azetidine ring acts as a structural motif rather than a naturally occurring residue. Because the molecule contains the essential amino acid functionality (carboxylic acid and ring-based amine), it is frequently advanced into protected intermediates that can be coupled under standard peptide assembly conditions, enabling systematic variation of neighboring residues and stereochemical context.
3. Pharmaceutical Intermediate Development
Azetidine-3-carboxylic acid is also used in pharmaceutical intermediate development as a compact chiral building block for larger synthetic routes toward azetidine-containing small molecules and advanced intermediates. Process and synthetic chemistry teams rely on this scaffold when designing analog series that require a rigid, nitrogen-containing ring to be installed at a specific position within a target framework. The free amino acid form provides a convenient starting point for downstream functionalization and protection strategies, supporting efficient conversion into the specific coupling or substitution-ready intermediates required for medicinal chemistry campaigns.
4. Structure-Activity Relationship Libraries
Azetidine-3-carboxylic acid is frequently selected for SAR library construction in academic and industrial medicinal chemistry settings where constrained amino acid motifs are used to map structure-property relationships. By enabling the systematic incorporation of an azetidine ring into peptide-like scaffolds or peptidomimetic backbones, it supports parallel synthesis of analogs that differ in adjacent residues, stereochemical configuration, or side-chain substitution patterns. Researchers value this building block as a way to generate chemically consistent, scaffold-defined series that can be compared using common analytical workflows such as LC-MS characterization and chromatographic purity profiling.
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