Description

L-S-T-Butylcysteine is a high-purity, non-natural amino acid derivative featuring a tert-butylthio protecting group on the cysteine sulfur atom. This compound is a critical chiral building block and protecting group reagent in advanced pharmaceutical synthesis and peptide chemistry. It is primarily utilized by research institutions and manufacturers in the pharmaceutical, biotechnology, and fine chemical sectors for the development of novel therapeutic agents and complex organic molecules.

Application

• Pharmaceutical Intermediate: A key chiral synthon in the asymmetric synthesis of active pharmaceutical ingredients (APIs), particularly those containing cysteine or disulfide motifs.
• Peptide Synthesis: Serves as a protected cysteine derivative in solid-phase and solution-phase peptide synthesis to prevent unwanted disulfide bond formation during assembly.
• Bioconjugation Chemistry: Used in the site-specific modification of proteins, antibodies, and other biomolecules via its reactive thiol group after deprotection.
• Ligand and Catalyst Preparation: Employed in the preparation of chiral ligands for asymmetric catalysis and metal complexes.
• Research & Development: A valuable tool compound in medicinal chemistry for structure-activity relationship (SAR) studies and prodrug design.
• Reference Standard: Used as an analytical standard in quality control laboratories for method development and validation.

Basic Information

Product Name	L-S-T-Butylcysteine
CAS No.	300583-35-1
Molecular Formula	C7H15NO2S
Molecular Weight	177.26 g/mol
Synonyms	(R)-2-Amino-3-(tert-butylthio)propanoic acid; L-Cysteine, S-(1,1-dimethylethyl)-; H-Cys(StBu)-OH; S-tert-Butyl-L-cysteine; tert-Butyl L-cysteine thioether; L-β-(tert-Butylthio)alanine; (2R)-2-Amino-3-[(2-methylpropan-2-yl)sulfanyl]propanoic acid
EINECS	Contact for details

Quality Control

Our L-S-T-Butylcysteine is manufactured under strict quality management systems. Each batch is subjected to comprehensive analytical testing, including chiral purity verification, to ensure it meets the high standards required for pharmaceutical research and development. A detailed Certificate of Analysis (COA) providing specifications for identity, purity (HPLC), chiral purity, and related substances is provided with every shipment.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated place at a controlled room temperature (15-25°C). The product is hygroscopic (moisture-sensitive) and should be handled under anhydrous conditions to maintain stability.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to structure
Identification (HPLC)	Retention time matches reference standard
Assay (HPLC)	≥98.0%
Chiral Purity (HPLC)	≥99.0% ee
Loss on Drying	≤0.5%
Residue on Ignition	≤0.1%
Heavy Metals	≤10 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.