Description

(R)-L-n-Fmoc-S-Mmt-A-Methylcysteine is a sophisticated, orthogonally protected amino acid derivative designed for advanced peptide synthesis. This compound is critical for researchers and manufacturers requiring precise stereochemical control and selective deprotection strategies in complex molecule assembly. It is primarily utilized by pharmaceutical R&D teams and fine chemical producers engaged in the development of peptide-based therapeutics, diagnostics, and novel bioactive compounds.

Application

• Solid-Phase Peptide Synthesis (SPPS): Serves as a key building block for introducing the non-proteinogenic amino acid (R)-α-methylcysteine into peptide chains, enabling the creation of peptides with enhanced metabolic stability and conformational constraints.
• Peptidomimetic Drug Discovery: Essential for constructing peptide analogs and mimetics where the S-Mmt (monomethoxytrityl) protecting group allows for selective thiol deprotection orthogonal to Fmoc removal, facilitating complex side-chain modifications.
• Conjugation Chemistry: The free thiol group, revealed after selective S-Mmt deprotection, is a crucial handle for site-specific bioconjugation, such as forming disulfide bridges or coupling with maleimide-functionalized molecules (e.g., linkers, fluorophores, or drug payloads).
• Research & Process Development: Used in academic and industrial laboratories for method development in synthetic organic chemistry and for scaling up custom peptide sequences for preclinical studies.
• Production of Constrained Peptides: The α-methyl group introduces a chiral center that restricts backbone conformation, making this derivative valuable for studying structure-activity relationships (SAR) and designing potent, selective peptide ligands.

Basic Information

Product Name	(R)-L-n-Fmoc-S-Mmt-A-Methylcysteine
CAS No.	1198791-74-0
Molecular Formula	C39H35NO5S
Molecular Weight	629.76 g/mol
Synonyms	Fmoc-(R)-α-Me-Cys(S-Mmt)-OH; N-[(9H-Fluoren-9-ylmethoxy)carbonyl]-S-[(4-methoxyphenyl)diphenylmethyl]-(R)-α-methyl-L-cysteine; (R)-2-(((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-2-methyl-3-((4-methoxyphenyl)diphenylmethyl)thio)propanoic acid; (R)-N-Fmoc-S-Mmt-α-methylcysteine; Fmoc-(R)-α-methylcysteine(S-Mmt); (R)-Fmoc-α-Me-Cys(Mmt)-OH; (2R)-2-{[(9H-Fluoren-9-ylmethoxy)carbonyl]amino}-2-methyl-3-{[bis(4-methoxyphenyl)(phenyl)methyl]sulfanyl}propanoic acid
EINECS	Contact for details

Quality Control

Every batch of (R)-L-n-Fmoc-S-Mmt-A-Methylcysteine is manufactured under strict quality management systems and undergoes comprehensive analytical testing to ensure identity, purity, and consistency. Our standard quality commitment includes HPLC purity ≥95% (with typical batches exceeding 98%), confirmation of stereochemical integrity, and stringent control of residual solvents. A detailed Certificate of Analysis (COA) providing full chromatographic data, specific optical rotation, and NMR/FTR confirmation is supplied with each shipment.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C or below under an inert atmosphere (e.g., argon or nitrogen) for long-term stability. This product is hygroscopic (moisture-sensitive) and light-sensitive. Allow the sealed container to equilibrate to room temperature before opening to minimize moisture condensation. For short-term use (under one week), storage at 2-8°C in a desiccator is acceptable.

Specification

Item	Specification
Appearance	White to off-white powder
Identification (HPLC)	Retention time corresponds to reference standard
Identification (NMR)	Spectrum consistent with structure
Purity (HPLC)	≥ 95.0%
Specific Optical Rotation	Contact for details
Water Content (KF)	≤ 1.0%
Heavy Metals	≤ 20 ppm

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