L-3-Thiolnorleucine is a non-proteinogenic, sulfur-containing amino acid derivative classified as a thio-functional analog of norleucine, featuring a straight-chain side chain terminating in a thiol group at the 3-position relative to the amino acid backbone. The molecule contains a free amino group and a free carboxyl group on the alpha carbon and bears a terminal thiol side chain that can undergo oxidation-reduction chemistry and form reversible or stable sulfur-based linkages under appropriate conditions, with the L stereochemical designation indicating the configuration at the alpha carbon. In peptide and chemical biology workflows, it is used as a building block for incorporating thiol-bearing residues into synthetic peptides or peptide-related intermediates, enabling subsequent conjugation, crosslinking, or site-specific functionalization via the thiol handle.
CAT No: CP09303
L-3-Thiolnorleucine is an L-configured, thioether-containing amino acid analog in which the side chain bears a thiol functionality at the 3-position relative to the backbone. The molecule contains the canonical alpha-amino and alpha-carboxyl groups, with a free sulfhydryl that can participate in nucleophilic and redox-related transformations while also enabling selective derivatization. As a chiral amino acid intermediate, it can be incorporated into peptide-like structures through standard amide bond formation, provided that the thiol reactivity is managed using appropriate protection or in situ handling. The presence of both an ionizable carboxylate and a functional thiol gives rise to pH-dependent speciation and practical considerations for coupling chemistry, purification, and downstream functional group conversion.
1. Peptide Synthesis
L-3-Thiolnorleucine supports peptide building block preparation for solid-phase or solution-phase assembly when its side-chain thiol is protected to prevent disulfide formation and thiol-mediated side reactions during coupling. The alpha-amino and alpha-carboxylate enable conventional peptide coupling to form amide linkages, while the L-stereocenter preserves defined stereochemistry at the residue position. Thiol-protection strategies such as S-alkyl or S-acyl forms can be used to maintain compatibility with common coupling reagents, followed by controlled deprotection to regenerate the free sulfhydryl for subsequent conjugation or native-thiol display. The resulting thiol-containing peptides and peptide fragments are useful for studying cysteine-mimetic behavior and for generating peptide scaffolds that require a reactive handle at a defined position.
2. Chemical Biology Probes
L-3-Thiolnorleucine functions as a biochemical research intermediate for installing a thiol-bearing residue analog in chemical biology constructs, including activity-based probes and redox-sensitive labeling reagents. The side-chain sulfhydryl can be selectively targeted by electrophilic labeling chemistries to generate stable thioether adducts, enabling site-specific tagging of peptides, small molecules, or biomolecule fragments. The amino acid backbone supports incorporation into peptide conjugates where the L-configuration and fixed side-chain geometry influence molecular recognition and labeling position. Downstream derivatization can produce fluorescent, affinity, or crosslinking reagents that rely on thiol chemistry to map binding environments or monitor thiol-dependent processes in biochemical assays.
3. Bioconjugation Chemistry
L-3-Thiolnorleucine is suitable for bioconjugation workflows that require a defined thiol handle for conjugation to proteins, polymers, or surfaces. The free thiol group can undergo controlled coupling to maleimide-, haloacetamide-, or other thiol-reactive electrophiles to form thioether linkages, while the amino acid-derived scaffold helps maintain a predictable attachment site when used in peptide or linker constructs. The L-amino acid stereochemistry can be retained through incorporation into linkers that position the reactive sulfhydryl at a controlled distance from the conjugation locus. The resulting conjugates can serve as analytical standards, immobilized capture reagents, or functional biomolecule derivatives used in binding studies and material-facing biochemical workflows.
4. Side-Chain Functionalization
L-3-Thiolnorleucine enables side-chain functionalization strategies that transform the sulfhydryl into diverse chemical motifs for synthetic organic chemistry and peptidomimetic design. The thiol can be oxidized to disulfides for reversible crosslinking, alkylated to generate thioether analogs with altered polarity, or used as a nucleophile for constructing thioester or thioamide derivatives under controlled conditions. The amino acid framework provides a chiral, stereochemically defined platform for preparing libraries of thiol-derived analogs that can be compared in structure-activity relationship studies or used to tune physicochemical properties such as hydrophobicity and conformational preference. Downstream, the thiol-derived products can act as intermediates for further functional group interconversion, including heteroatom substitution patterns relevant to sulfur-containing pharmacophores and biomolecule mimetics.
5. Process Chemistry Intermediate
L-3-Thiolnorleucine is applicable as a process chemistry intermediate for manufacturing thiol-containing amino acid derivatives and protected analogs used in peptide and fine chemical production. The combination of an amino acid backbone and a reactive thiol allows conversion into protected forms that are compatible with industrial peptide coupling conditions, followed by deprotection to deliver the free sulfhydryl for final-stage conjugation or formulation steps. The stereochemical integrity of the L-center supports consistent residue identity in downstream synthetic sequences, which is important for reproducible product profiles in peptide analog manufacturing. The compound's functional group profile also supports scalable derivatization routes to thiol-reactive intermediates used in specialty chemical production, including sulfur-functional linkers and chiral building blocks for industrial chemical synthesis.
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