Description

L-Cysteine, Acetate (Ester), Hydrochloride (9Ci) is a chemically modified derivative of the essential amino acid L-Cysteine, where the carboxyl group is esterified with acetic acid and the amino group is present as a hydrochloride salt. This specific molecular configuration enhances its stability and solubility profile, making it a valuable intermediate for advanced synthesis. It is primarily sought by research institutions and manufacturers in the pharmaceutical and fine chemical sectors for applications in peptide synthesis, biochemical research, and as a building block for more complex active pharmaceutical ingredients (APIs).

Application

• Pharmaceutical Intermediate: A key chiral building block in the synthesis of complex peptides, proprietary drugs, and other bioactive molecules.
• Biochemical Research: Used as a protected form of cysteine in studies involving protein structure, enzyme mechanisms, and metabolic pathways.
• Fine Chemical Synthesis: Serves as a precursor for manufacturing specialty chemicals, catalysts, and ligands used in asymmetric synthesis.
• Reference Standard: Employed as a high-purity analytical standard in quality control laboratories for method development and validation.

Basic Information

Product Name	L-Cysteine, Acetate (Ester), Hydrochloride (9Ci)
CAS No.	66185-37-3
Molecular Formula	C5H10ClNO3S
Molecular Weight	199.65 g/mol
Synonyms	L-Cysteine acetate hydrochloride; Cysteine acetate ester hydrochloride; (R)-2-Amino-3-mercaptopropanoic acid acetate ester hydrochloride; Acetyl-L-cysteine ethyl ester hydrochloride (related form); N-Acetyl-L-cysteine ethyl ester hydrochloride (common alias); NSC 113939; S-Acetamido-L-cysteine ethyl ester hydrochloride; 2-Acetamido-3-mercaptopropionic acid ethyl ester hydrochloride
EINECS	Contact for details

Quality Control

Our L-Cysteine, Acetate (Ester), Hydrochloride is produced under a strict quality management system. Each batch is subjected to comprehensive analytical testing, including HPLC for purity and identity confirmation via IR and NMR spectroscopy, to ensure it meets exacting standards suitable for research and synthesis. A Certificate of Analysis (COA) detailing all test results is provided with every shipment to guarantee traceability and compliance with your specifications.

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). Due to its hygroscopic (moisture-sensitive) nature, the container must be kept tightly sealed after each use to prevent absorption of atmospheric moisture, which can compromise product integrity.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.0%
Optical Rotation [α]	Specific range available on COA
Loss on Drying	≤ 1.0%
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.