L-Norleucine is a naturally occurring, proteinogenic amino acid classified as an aliphatic (hydrophobic) amino acid, featuring a straight-chain side chain that is one methylene longer than leucine. The molecule contains a primary amino group and a carboxyl group on the α-carbon, with the side chain bearing only hydrocarbon functionality and the stereochemistry specified as L. L-Norleucine is used as a free amino acid building block for peptide synthesis and for studying structure-activity relationships in peptide and protein analogues where side-chain length and hydrophobic character are varied.
CAT No: CP08502
CAS No:327-57-1
Synonyms/Alias:L-Norleucine;327-57-1;NORLEUCINE;(S)-2-Aminohexanoicacid;Caprine;Glycoleucine;L-(+)-Norleucine;L-2-Aminohexanoicacid;2-Aminocaproicacid;(2S)-2-aminohexanoicacid;(S)-Norleucine;L-2-Aminohexanoate;H-Nle-OH;alpha-Aminocaproicacid;2S-amino-hexanoicacid;(S)-(+)-2-Aminohexanoicacid;2-Aminocaproate;(S)-2-Aminocaproicacid;2-Aminohexanoate;L(+)-Norleucine;Norleucine(VAN);(S)-Aminohexanoate;L-Aminohexanoicacid;L-Aminohexanoate;(S)-2-aminohexanoate
L-Norleucine is a straight-chain aliphatic amino acid with the stereogenic center at the alpha position, corresponding to the L configuration, and a primary amino group paired with a carboxylic acid functionality. The unbranched side chain (n-butyl-like) provides a hydrophobic, non-aromatic residue that behaves as a clean structural handle for peptide backbone incorporation and for side-chain functionalization without competing ring chemistry. As a free amino acid, L-norleucine participates in standard amino acid coupling chemistry after appropriate activation and can be protected as an N-protected derivative or converted to an ester to tune solubility and reactivity during synthesis. The compound's predictable reactivity profile makes it suitable as a chiral amino acid intermediate and as a platform for generating norleucine-containing peptide building blocks and downstream chemical derivatives.
1. Peptide Synthesis
L-Norleucine is applied in peptide synthesis workflows where a hydrophobic, non-aromatic residue is required to modulate folding, membrane affinity, or protease recognition patterns in peptide sequences. The alpha-amino and carboxyl groups enable formation of peptide bonds using protected amino acid strategies, typically via N-protection and carboxyl activation, while the L stereochemistry supports stereochemically consistent incorporation into growing chains. The straight-chain side chain can be used as a norleucine substitute in peptide libraries to probe how aliphatic length and steric environment influence conformational preferences. L-Norleucine can be converted into protected building blocks for solid-phase or solution-phase coupling, supporting construction of peptide analogs and peptidomimetics for biochemical research and structure-activity relationship studies.
2. Amino Acid Derivatization
L-Norleucine is utilized for amino acid derivatization routes that transform the side-chain and backbone functional groups into chemically addressable intermediates for fine chemical synthesis. The primary amino functionality can be protected or selectively functionalized, while the carboxyl group can be esterified or converted into activated derivatives to control chemoselectivity during multi-step synthesis. The unbranched hydrophobic side chain can be functionalized to introduce handles such as electrophiles, protected alcohols, or thioether-forming motifs, enabling downstream conjugation or incorporation into larger scaffolds. L-Norleucine derivatives therefore serve as chiral amino acid intermediates for constructing unnatural amino acid analogs, building blocks for medicinal chemistry fragments, and process-relevant intermediates in applied synthetic organic chemistry.
3. Chemical Biology Probes
L-Norleucine is applied in chemical biology and molecular recognition studies where norleucine-containing peptides act as probes for studying binding interfaces and enzymatic tolerance toward aliphatic substitutions. The L-configured alpha stereocenter ensures consistent stereochemical presentation of the backbone, while the hydrophobic side chain can be used to tune local packing and reduce aromatic or heteroatom-driven interactions. N- and C-terminal modification compatibility enables preparation of conjugatable peptide segments for affinity reagents, pull-down probes, or labeling substrates used in biochemical assays. L-Norleucine-based constructs can be further elaborated into fluorescent or affinity-tagged analogs through orthogonal protection and functional group interconversion, supporting mechanistic investigations and structure-function mapping.
4. Bioconjugation Chemistry
L-Norleucine is suitable for bioconjugation chemistry workflows that require a defined amino acid residue as part of conjugatable peptide or linker architectures. The amino acid backbone can be engineered into N-protected intermediates for controlled coupling, and the carboxyl group can be activated or transformed into amide-forming derivatives to attach to biomolecular targets or carrier proteins. The hydrophobic norleucine side chain can influence solubility and microenvironment around the conjugation site, which can be relevant when designing linkers for biomolecule labeling and multivalent binding formats. L-Norleucine therefore supports downstream formation of stable amide and peptide-derived linkages used in biomolecule modification and applied chemical biology reagent development.
5. Pharmaceutical Manufacturing Intermediates
L-Norleucine is employed as a chiral amino acid intermediate in pharmaceutical manufacturing contexts where peptide-like fragments, peptidomimetic motifs, or stereochemically defined building blocks are synthesized at scale. The compound's functional groups allow conversion into protected amino acid derivatives that are compatible with industrial peptide coupling chemistry, including controlled N-protection and carboxyl activation strategies that minimize side reactions. The non-aromatic, hydrophobic side chain can be incorporated into intermediate structures to tune lipophilicity and solid-state behavior of downstream molecules without introducing additional heteroatom complexity. L-Norleucine-based intermediates can thus feed into fine chemical synthesis routes for producing norleucine-containing drug candidates, process intermediates, and characterized reference materials used in manufacturing development and analytical method support.
6. Analytical Research Standards
L-Norleucine is used in analytical research settings as a reference amino acid and as a precursor for preparing labeled or derivatized standards that support method development and quantitative analysis. The defined L stereochemistry and clean aliphatic side chain enable unambiguous identification in chromatographic and mass spectrometric workflows when used as a calibration component or as part of peptide standard mixtures. Derivatization of the amino and carboxyl functionalities can produce stable analytical derivatives suitable for improving detection sensitivity and chromatographic behavior. L-Norleucine-derived standards can be applied to verify amino acid composition, monitor synthetic intermediates, and support quality control of peptide-building-block preparations in both academic and industrial laboratories.
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