DL-3-Thiolnorleucine

DL-3-Thiolnorleucine contains a norleucine-derived amino acid skeleton with a side-chain thiol at the 3-position, paired with a free or derivatizable amino functionality and a carboxylic acid (or corresponding protected/activated form depending on the supplied grade). The molecule is present as a DL mixture, so stereochemical outcomes at the α-carbon can be tracked or resolved in downstream chemistry for stereodefined peptide analogs. The thiol group can participate in thioether formation, disulfide exchange, and thiol-maleimide conjugation chemistry, while the amino and carboxyl groups support peptide coupling and amino acid derivatization workflows. As a sulfur-containing amino acid building block, DL-3-Thiolnorleucine functions as a practical intermediate for incorporating redox-active or chemically addressable side chains into peptides, peptidomimetics, and functional biomolecule conjugates.

1. Peptide Synthesis

DL-3-Thiolnorleucine supports peptide building block preparation where the α-amino and carboxyl functionalities enable standard amide bond formation after appropriate activation and protection management. The side-chain thiol at C-3 can be protected as a thioether or thiol-protecting group during coupling to prevent disulfide scrambling, then deprotected to furnish a reactive handle for subsequent steps. DL stereochemistry can be leveraged for library synthesis where mixed stereoisomers are screened, or resolved later to obtain a single stereochemical series for structure-activity relationship studies. Downstream, thiol-bearing peptide fragments can be assembled into longer sequences and used to generate disulfide-linked analogs, thioether-stabilized variants, or thiol-terminated constructs for conjugation chemistry.

2. Chemical Biology Conjugation

DL-3-Thiolnorleucine is suitable for chemical biology workflows that require a thiol-reactive amino acid side chain for site-specific labeling and biomolecule modification. The pendant thiol can undergo selective conjugation to electrophilic capture reagents such as alkyl halides, activated disulfides, or maleimide-functional partners, enabling attachment of fluorophores, affinity tags, or probes to peptide or protein scaffolds. The amino acid backbone can be incorporated into peptide handles that improve solubility and orientation, while the thiol provides a chemically addressable point for downstream bioconjugation steps. Mixed DL stereochemistry may be tolerated for probe development where labeling chemistry dominates, or used as a starting point for stereodefined analog generation to probe stereochemical effects on biomolecular recognition.

3. Peptidomimetics And SAR

DL-3-Thiolnorleucine enables peptidomimetic construction by introducing a sulfur-containing side chain that can be tuned through oxidation state control, thioether substitution, or disulfide/thiol interconversion strategies. The α-amino acid framework supports incorporation into constrained analogs, while the C-3 thiol can be transformed into stable thioethers or oxidized to disulfide motifs to modulate conformational behavior and chemical stability. DL stereochemistry can be exploited for rapid SAR mapping across stereochemical series, followed by enrichment or resolution to interpret stereochemical contributions to binding or reactivity profiles. The resulting thiol-derived analogs serve as practical intermediates for medicinal chemistry campaigns focused on structure-activity relationship studies and functional group-dependent scaffold optimization.

4. Process Chemistry Intermediate

DL-3-Thiolnorleucine can function as a sulfur-functional amino acid intermediate for fine chemical synthesis and process chemistry routes that require a thiol-bearing building block for downstream derivatization. The presence of both amino and carboxyl functionalities supports conversion to activated derivatives (for peptide coupling) and to protected forms that can be carried through multi-step manufacturing sequences with controlled deprotection timing. Thiol chemistry provides a handle for controlled formation of thioethers or disulfide-linked intermediates, which can be further processed into specialty reagents, peptide fragments, or functional polymers. Downstream synthetic utility includes preparation of chemically addressable intermediates for industrial-scale peptide analog production and for manufacturing of thiol-reactive conjugation components.

5. Analytical Standards And Labeling

DL-3-Thiolnorleucine is applicable to analytical research where thiol-containing amino acid standards are needed for method development, quantification, and monitoring of sulfur-containing species. The thiol side chain can be derivatized to stable adducts for chromatographic detection, enabling tracking of thiol preservation versus oxidation during sample handling and synthesis. The amino acid structure also supports use as a reference material for verifying peptide coupling outcomes when thiol-bearing residues are introduced into synthetic sequences. DL stereochemistry may be used to generate calibration sets for mixed stereoisomer profiles, while subsequent stereochemical resolution can support more discriminating analytical characterization of stereodefined derivatives.

1. Effect of Probiotic Lactobacillus plantarum on Streptococcus mutans and Candida albicans Clinical Isolates from Children with Early Childhood Caries

2. The effect of sex on immune responses to a homocitrullinated peptide in the DR4-transgenic mouse model of Rheumatoid Arthritis

3. Therapeutic potential of an intestinotrophic hormone, glucagon-like peptide 2, for treatment of type 2 short bowel syndrome rats with intestinal bacterial and fungal dysbiosis

4. Investigating Potential Interactions Between Neurohypophyseal Peptides, their Drug Analogs, and Coagulation Factor VIII

5. Immune responses to peptides containing homocitrulline or citrulline in the DR4-transgenic mouse model of rheumatoid arthritis