H-alpha-Me-L-Leu-OH is a free, non-proteinogenic amino acid derivative featuring an α-methyl substituent on the amino acid backbone and an L-leucine-derived side chain with an isobutyl group. The molecule contains a primary amino group and a carboxylic acid (-COOH), with the α-methyl substitution creating a sterically constrained backbone while retaining the L stereochemical designation indicated in the name. It is used in peptide and amino acid chemistry as a building block for structure-activity studies and for preparing modified peptides or analogues where backbone methylation is used to probe conformational effects and chemical stability.
CAT No: CP25139
CAS No:105743-53-1
Chemical Name:(S)-a-Methylleucine (>98%, >99%ee)
H-alpha-Me-L-Leu-OH is a chiral amino acid derivative in which the alpha carbon bears a methyl substituent (α-methylated) and the side chain corresponds to L-leucine, giving a sterically defined, hydrophobic building block with a free carboxylic acid and a primary amino group. The α-methyl stereocenter constrains backbone conformations and can influence peptide secondary structure propensity when incorporated into amide linkages. The presence of an unprotected amino acid functionality makes the compound directly relevant to protected amino acid chemistry, where selective N-protection and carboxyl activation are used to enable controlled peptide coupling. The combination of a constrained chiral center and a branched aliphatic side chain also supports downstream derivatization to carboxylate esters, amide derivatives, and stereochemically informative intermediates for synthetic and biochemical studies.
1. Peptide Synthesis
H-alpha-Me-L-Leu-OH is applied in peptide building block preparation where α-methylation and the L-leucine side chain provide a conformationally biased residue for amide bond construction. The free carboxylic acid and amino group can be converted into peptide-grade protected forms, enabling standard coupling strategies after activation of the carboxylate and protection of the amine to control chemoselectivity. The α-methyl stereocenter can be leveraged to modulate backbone geometry during peptide assembly, supporting the synthesis of α-methylated peptide analogs used in structure-function investigations. Downstream, the residue can be incorporated into linear peptides, cyclic scaffolds, or fragment-based constructs to generate sequence-defined materials for synthetic methodology development and peptide science workflows.
2. Peptidomimetics And SAR
H-alpha-Me-L-Leu-OH serves in peptidomimetic and SAR studies by providing a stereochemically constrained amino acid motif that can be substituted for native residues to probe conformational effects. The α-methyl substituent and hydrophobic leucine side chain influence intramolecular packing and can alter hydrogen-bonding patterns when the compound is incorporated as an amide in larger frameworks. The amino acid functionality supports derivatization into N-protected, carboxyl-activated intermediates that enable iterative synthesis of analog libraries with defined stereochemistry. The resulting α-methylated analogs can be used as chemically tractable SAR probes, enabling systematic evaluation of how stereochemical and side-chain changes propagate through peptide-like structures.
3. Chiral Building Block Intermediate
H-alpha-Me-L-Leu-OH is suitable as a chiral amino acid intermediate for stereoselective synthesis routes that require a defined α-methyl stereocenter and an L-configured side chain. The compound's amino and carboxyl groups enable conversion into protected derivatives such as N-protected amino acids and carboxylate esters, which are commonly used to manage reactivity during multi-step fine chemical synthesis. The constrained chiral center can be retained through downstream transformations, supporting the preparation of enantiopure intermediates for stereochemically defined scaffolds, including α-methylated peptidomimetic fragments and related heteroatom-functionalized analogs. The resulting intermediates can feed into medicinal chemistry-oriented synthetic sequences and broader chiral building block manufacturing workflows.
4. Chemical Biology Labeling
H-alpha-Me-L-Leu-OH can be utilized in chemical biology research as a labeled or functionalized amino acid precursor for constructing hydrophobic, α-methylated segments within probe molecules. The free amino group and carboxyl group enable attachment of reporter handles through controlled derivatization, including formation of amide-linked conjugates or ester/acid activation for subsequent coupling to biomolecule-reactive motifs. The leucine-like side chain and α-methyl stereocenter can help tune hydrophobicity and local conformational bias in peptide-based probes, which may affect binding mode or stability in assay contexts. Downstream, the compound can be incorporated into peptide conjugates, affinity tags, or probe fragments that support biochemical investigation and molecular interaction mapping.
5. Pharmaceutical Manufacturing Intermediates
H-alpha-Me-L-Leu-OH is relevant to pharmaceutical manufacturing as a chiral amino acid starting material for producing α-methylated peptide intermediates used in synthetic sequences toward active pharmaceutical ingredient candidates or related process chemistry targets. The amino acid's functional groups can be transformed into N-protected derivatives and activated carboxyl forms that are compatible with scalable peptide coupling operations and controlled deprotection steps. The stereochemical integrity of the α-methylated center supports reproducible formation of defined amide linkages during manufacturing-scale synthesis of peptide-like intermediates. The compound's role as a stereochemically specified chiral input supports downstream intermediate preparation for fine chemical production, including the generation of sequence-defined fragments used in larger assembly processes.
6. Analytical Research Standards
H-alpha-Me-L-Leu-OH can be employed in analytical research for method development and stereochemical verification of α-methylated amino acid derivatives. The presence of both amino and carboxylic acid functionalities allows conversion into derivatized standards, such as esterified or N-protected forms, that improve chromatographic behavior and support mass spectrometric detection. The defined L-configuration and α-methyl stereocenter make the compound suitable for calibrating analytical workflows that distinguish stereoisomeric amino acid building blocks and monitor incorporation of α-methylated residues in peptide hydrolysates. Downstream, derivatized analogs prepared from this amino acid can serve as reference materials for quality control of protected amino acid intermediates and peptide coupling products in research and industrial settings.
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