Boc-D-Cys(NPys)-OH is a protected amino acid derivative featuring a D-configured cysteine backbone bearing an N-(NPys) thioether substituent and an N-terminal Boc (tert-butoxycarbonyl) protecting group. The molecule contains both an amino functionality masked by Boc and a carboxyl group as a free acid, while the cysteine side chain is functionalized with an NPys group that modifies the thiol reactivity and provides a handle for controlled chemoselectivity during peptide assembly or subsequent derivatization. In synthesis and chemical biology workflows, this protected analogue is used as a building block for stepwise peptide synthesis where the Boc group supports amide-bond formation and the NPys-modified sulfur functionality helps manage side-chain participation, enabling preparation of cysteine-containing peptide structures and related amino acid derivatives for structural or labeling studies.
CAT No: CP26645
CAS No:200350-73-8
Synonyms/Alias:Boc-S-3-nitro-2-pyridinesulfenyl-D-cysteine;200350-73-8;Boc-D-Cys(NPys)-OH;CTK8F0145;ZINC2560675;RT-011796
Boc-D-Cys(NPys)-OH is a protected D-cysteine derivative bearing a Boc-protected alpha-amino group and an NPys side-chain protection on the thiol-bearing cysteine functionality. This amino acid building block is designed for controlled incorporation into peptide sequences where the cysteine side chain must remain masked during assembly. The D-configuration supports stereochemically defined peptide and peptidomimetic design, while the orthogonal protection pattern helps maintain chemoselectivity across multi-step coupling and deprotection workflows.
1. D-Cysteine Peptide Building Block
Boc-D-Cys(NPys)-OH is used as a cysteine residue building block for peptide synthesis when stereochemical inversion at the cysteine position is required for structure-activity relationship studies, protease-stability optimization, or conformational control in peptidomimetic scaffolds. Peptide synthesis groups in academic and industrial settings rely on Boc-protected amino acids like this one to assemble defined sequences using protected cysteine side chains that remain inert toward common coupling conditions. The NPys thiol protection supports downstream handling of peptides that would otherwise be prone to side reactions associated with free thiols, enabling reliable sequence assembly and purification of intermediates and final constructs.
2. Side-Chain-Protected Peptide Intermediates
Boc-D-Cys(NPys)-OH serves as a practical intermediate for preparing cysteine-containing peptide fragments where the thiol functionality must be masked until a later stage of synthesis or modification. Custom peptide manufacturing teams and medicinal chemistry groups frequently use such protected cysteine derivatives to build segment libraries, generate late-stage functionalized peptides, and preserve chemoselectivity during iterative coupling and fragment condensation. The combination of Boc at the alpha-amino position and NPys on the side-chain thiol helps reduce unwanted disulfide formation and thiol-mediated side reactions during peptide assembly, which is particularly valuable when cysteine is positioned in regions that are sensitive to oxidation or nucleophilic interference.
3. Peptidomimetic Synthesis Programs
Boc-D-Cys(NPys)-OH is incorporated into peptidomimetic development workflows that require D-amino acid content to tune backbone stereochemistry and influence biological recognition profiles in structure-driven design campaigns. Medicinal chemistry researchers use D-configured, side-chain-protected cysteine building blocks to access stereochemically defined analogs for SAR screening, including analog series where the cysteine residue contributes to local geometry, hydrogen-bonding patterns, or conformational preferences. By keeping the cysteine thiol protected during synthesis, this derivative supports consistent preparation of analogs that can later be converted into thiol-reactive or thiol-derived functionalities under controlled conditions, aligning with downstream derivatization strategies used in chemical biology and drug discovery chemistry.
4. Chemoselective Late-Stage Functionalization
Boc-D-Cys(NPys)-OH is selected when a cysteine-containing peptide or peptide fragment needs to be carried through synthesis with the thiol functionality protected for chemoselective conversion at a later stage. Chemical biology and materials-oriented peptide developers often prepare cysteine-bearing intermediates that can be transformed into thiol-reactive handles or thiol-derived motifs after peptide assembly, enabling controlled conjugation to electrophiles or surface/biopolymer attachment chemistries. The NPys side-chain protection supports maintaining the integrity of the cysteine residue through coupling steps and intermediate handling, which helps reduce batch-to-batch variability caused by premature thiol oxidation or side reactions, improving reproducibility of late-stage functionalization workflows.
1. Urinary Metabolites Associated with Blood Pressure on a Low-or High-Sodium Die
3. Adipose tissue is a key organ for the beneficial effects of GLP-2 metabolic function
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