Boc-D-Cys(Bzl)-OH is a protected amino acid derivative based on D-cysteine bearing a benzyl-protected thiol side chain, with the α-amino group masked as a Boc carbamate and the α-carboxyl group present as a free acid. The molecule contains a Boc-protected nitrogen, a benzyl thioether substituent on sulfur that modulates side-chain nucleophilicity, and stereochemistry specified as the D configuration at the α-carbon while retaining the cysteine backbone. In peptide synthesis workflows, this protected analogue functions as a stepwise coupling building block whose protected groups help control chemoselectivity during amide bond formation and subsequent side-chain deprotection steps in the preparation of cysteine-containing peptides and related conjugates.
CAT No: CP25120
CAS No:102830-49-9
Synonyms/Alias:N-Boc-S-benzyl-D-cysteine;Boc-D-Cys(Bzl)-OH;102830-49-9;Boc-S-benzyl-D-cysteine;s-benzyl-n-(tert-butoxycarbonyl)-d-cysteine;AmbotzBAA5410;AC1Q1MUE;AC1Q5XMI;Boc-(S)-benzyl-D-Cys;AC1L2VW3;Alanine,3-(benzylthio)-N-carboxy-,N-tert-butylester,L-;N-((1,1-Dimethylethoxy)carbonyl)-S(phenylmethyl)-L-cysteine;98920_ALDRICH;L-Cysteine,N-((1,1-dimethylethoxy)carbonyl)-S-(phenylmethyl)-;SCHEMBL3582418;98920_FLUKA;CTK8C5111;MolPort-003-939-992;ZINC2390934;EINECS225-772-8;ANW-74147;AR-1L4015;AKOS015836473;AKOS015888716;NSC164041
Chemical Name:N-alpha-t-Butyloxycarbonyl-S-benzyl-D-cysteine
Boc-D-Cys(Bzl)-OH is a protected cysteine building block featuring the D-stereochemistry at the amino acid center, a Boc-protected amino group, and a benzyl-protected thiol side chain (Cys(Bzl)). This protection pattern is commonly used to control chemoselectivity during peptide assembly and to preserve the cysteine sulfur in the presence of peptide coupling and deprotection steps. The compound is therefore a practical reagent for preparing cysteine-containing peptide segments and related pharmaceutical intermediates where side-chain thiol handling must be managed carefully.
1. Solid-Phase Peptide Synthesis
Boc-D-Cys(Bzl)-OH is used by peptide synthesis groups to introduce D-cysteine residues into peptide sequences while maintaining the thiol as a benzyl-protected thioether precursor during chain elongation. In solid-phase peptide synthesis workflows, the Boc-protected amino functionality supports stepwise segment construction under conditions that require the sulfur to remain protected from undesired oxidation or side reactions. This makes the reagent particularly relevant for generating D-amino-acid peptides, cysteine-containing fragments, and stereochemically defined peptide standards used in peptide mapping and process development.
2. D-Cysteine Peptide Building Blocks
Boc-D-Cys(Bzl)-OH supports the preparation of stereochemically defined D-cysteine-containing peptides for chemical biology and peptide engineering studies where the D-configuration is intentionally incorporated to probe sequence effects, stability trends, or structure-property relationships. Researchers developing peptide libraries or performing structure-activity relationship work rely on protected cysteine building blocks to ensure that the cysteine side chain does not interfere with coupling efficiency or downstream manipulations. The benzyl-protected thiol further enables controlled conversion to reactive thiol-containing intermediates later in the synthesis workflow when needed for conjugation or selective functionalization.
3. Pharmaceutical Intermediate Development
Boc-D-Cys(Bzl)-OH is also used in medicinal chemistry and pharmaceutical intermediate development as a protected amino acid unit for assembling cysteine-bearing intermediates that require controlled sulfur protection throughout multi-step synthesis. Process chemists and custom synthesis teams often choose this protection scheme to reduce variability caused by sulfur oxidation and to keep the side chain compatible with typical peptide-coupling or fragment-condensation strategies. The resulting protected cysteine-containing intermediates can be advanced toward further functionalization steps used in the manufacture of peptide-like scaffolds and cysteine-dependent building blocks for downstream R&D programs.
4. Controlled Thiol Functionalization Precursors
Boc-D-Cys(Bzl)-OH serves as a reliable precursor for workflows that require cysteine thiol availability at a later stage, such as preparing thiol-bearing peptide intermediates for subsequent derivatization. By keeping the sulfur protected as a benzyl thioether during peptide segment construction, the reagent helps maintain chemoselectivity until the project calls for generating a free thiol or a thiol-reactive intermediate. This approach is commonly applied in peptide conjugation development and in the preparation of cysteine-functionalized fragments used for controlled labeling, crosslinking studies, or site-specific attachment strategies in chemical biology research.
If you have any peptide synthesis requirement in mind, please do not hesitate to contact us at . We will endeavor to provide highly satisfying products and services.
Creative Peptides is a trusted CDMO partner specializing in high-quality peptide synthesis, conjugation, and manufacturing under strict cGMP compliance. With advanced technology platforms and a team of experienced scientists, we deliver tailored peptide solutions to support drug discovery, clinical development, and cosmetic innovation worldwide.
From custom peptide synthesis to complex peptide-drug conjugates, we provide flexible, end-to-end services designed to accelerate timelines and ensure regulatory excellence. Our commitment to quality, reliability, and innovation has made us a preferred partner across the pharmaceutical, biotechnology, and personal care industries.
Read More