(R)-2-amino-2-cyclobutylacetic acid hydrochloride
[CAS# 1958125-89-7]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives
• Name: (R)-2-amino-2-cyclobutylacetic acid hydrochloride
• Synonyms: (2R)-2-amino-2-cyclobutylacetic acid;hydrochloride
• Protein Sequence: X
• Molecular Formula: C₆H₁₂ClNO₂
• Molecular Weight: 165.62
• CAS Registry Number: 1958125-89-7
• SMILES: C1CC(C1)[C@H](C(=O)O)N.Cl

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H315-H319-H335
• Precautionary Statements: P261-P305+P351+P338

Discovory and Applicatios

(R)-2-Amino-2-cyclobutylacetic acid hydrochloride is a chiral amino acid derivative, structurally derived from glycine, in which the amino and carboxylate groups remain, and the α-carbon rather than bearing hydrogen is substituted by a cyclobutyl ring. Its free-base counterpart has the molecular formula C₆H₁₁NO₂ and molecular weight of approximately 129.16 g mol⁻¹; the hydrochloride salt corresponds to C₆H₁₂ClNO₂ with molecular weight around 165.62 g mol⁻¹. Industrie and catalogue entries list its CAS number as 1958125-89-7 for the hydrochloride form.

The discovery or first preparation of this specific amino acid derivative is not widely documented in the primary literature. It appears primarily as a research reagent in chiral synthesis and as a component for peptide or enzyme-substrate studies rather than as a naturally occurring amino acid. The substitution of a cyclobutyl ring on the α-carbon alters steric and electronic properties compared with glycine or other standard amino acids, rendering it suitable as a building block for the synthesis of constrained peptides, enzyme inhibitors, or novel ligands. The hydrochloride format increases its solubility in aqueous systems and ease of handling for synthetic protocols.

In practical application, (R)-2-Amino-2-cyclobutylacetic acid hydrochloride has been used as a chiral auxiliary or as a non-standard amino acid incorporated into peptides in medicinal chemistry research, particularly when increased steric bulk at the α-carbon is desired for controlling peptide conformation or for probing enzyme specificity. Its use also extends to the synthesis of custom amino acid derivatives, ligands for metal centres, and as a precursor in the preparation of more complex chiral scaffolds. Because the cyclobutyl substitution restricts conformational flexibility and impacts backbone dihedral angles when incorporated into peptides, it can influence secondary structure and stability of peptide models.

From the perspective of chemical synthesis and handling, the compound (R)-2-Amino-2-cyclobutylacetic acid hydrochloride is typically handled as a solid salt, stored under recommended conditions (dry, cool, and sealed) to maintain purity and avoid moisture uptake. The amino acid functionality confers acid–base behaviour, so that in free base form deprotonation/protonation equilibria occur; the hydrochloride salt form ensures the amino group remains protonated, increasing water solubility and facilitating subsequent reactions (such as amide-bond formation, esterification, or peptide coupling). The presence of the cyclobutyl ring increases hydrophobicity and steric bulk relative to glycine, and this must be considered in solvation, coupling efficiency and the design of downstream synthetic steps.

Although the compound is commercially available from several suppliers, peer-reviewed publications specifically detailing its physical properties, stereochemistry confirmation, or detailed application in large-scale synthesis are limited. Because it is a research-reagent amino acid rather than a common biological or industrial product, the literature tends to reference its catalogue listings rather than detailed mechanistic studies. Researchers employing it in peptide or ligand design must validate stereochemical purity, coupling efficiency and behaviour under their specific synthetic conditions.

In summary, (R)-2-Amino-2-cyclobutylacetic acid hydrochloride is a chiral non-standard amino acid derivative useful as a building block in synthetic and medicinal chemistry, particularly when conformationally constrained or sterically bulky α-substituents are required. Its hydrochloride salt form enhances solubility and handling for synthetic procedures. While detailed mechanistic documentation in the public literature is sparse, it is a valuable reagent for specialized chiral and peptide-based work.