Fmoc-D-Pen(Bzl)-OH is an Fmoc-protected D-penicillamine derivative in which the amino acid core is substituted at the side chain with a benzyl-protected thioether, and the carboxyl group is present as a free acid. The molecule contains an N-Fmoc carbamate that masks the amino functionality for chemoselective coupling, while the benzyl group on the side-chain sulfur provides a hydrophobic, thioether-stabilizing substituent and the stereochemistry is specified as D at the amino acid center. In peptide synthesis workflows, this protected amino acid is used as a building block to introduce the penicillamine side chain bearing a benzyl thioether, supporting the preparation of peptides and related derivatives for structure-activity studies, chemical biology labeling strategies, or analytical method development.
CAT No: CP26359
CAS No:139551-73-8
Synonyms/Alias:Fmoc-S-benzyl-D-penicillamine;139551-73-8;Fmoc-D-Pen(Bzl)-OH;SCHEMBL9622660;CTK8E5945;ZINC2517147;6861AH;Fmoc-beta,beta-dimethyl-D-Cys(Bzl)-OH;RT-013040
Fmoc-D-Pen(Bzl)-OH is a D-configured penicillamine derivative bearing an Fmoc-protected amino group, a free carboxylic acid, and a benzyl-protected thiol equivalent through the Pen(Bzl) motif. The stereogenic center at the penicillamine backbone and the side-chain sulfur functionality make the molecule a chemically recognizable chiral amino acid building block for thiol-aware peptide and conjugation strategies. The Fmoc carbamate enables base-mediated removal under standard peptide synthesis conditions, while the carboxylic acid supports coupling to form amide linkages. The benzyl thioether/thiol-protected character provides a handle for later deprotection or transformation, supporting downstream access to sulfur-containing intermediates used in peptide science and synthetic chemistry.
1. Peptide Synthesis
Fmoc-D-Pen(Bzl)-OH is applied in peptide building block preparation where D-penicillamine stereochemistry and sulfur side-chain chemistry are required for thioether- or thiol-derived peptide analogs. The Fmoc-protected N-terminus supports stepwise solid-phase or solution-phase peptide coupling, while the free C-terminal carboxylic acid participates in amide bond formation using standard coupling reagents. The Pen(Bzl) side-chain protection strategy helps manage sulfur reactivity during chain assembly, reducing undesired oxidation or side reactions. Formation of sulfur-containing peptide sequences from this protected amino acid derivative enables access to cysteine-mimetic motifs, redox-sensitive scaffolds, and chemically defined peptide intermediates for further modification.
2. Side-Chain Functionalization
Fmoc-D-Pen(Bzl)-OH is used in side-chain functionalization workflows that rely on controlled sulfur chemistry for subsequent derivatization. The benzyl-protected sulfur functionality can be converted into thiol-bearing or sulfur-reactive intermediates after appropriate deprotection or transformation steps, enabling conjugation to electrophiles or incorporation into disulfide-forming motifs. The preserved stereocenter supports stereochemically defined sulfur positioning, which is relevant for structure-function studies of thiol-containing peptides and peptidomimetics. Downstream generation of functional sulfur derivatives supports synthetic organic chemistry routes and biochemical reagent preparation where thiol reactivity must be introduced at a planned stage.
3. Bioconjugation Chemistry
Fmoc-D-Pen(Bzl)-OH is suitable for bioconjugation and chemical biology applications that require a protected amino acid precursor for sulfur-based attachment chemistries. The Fmoc group allows orthogonal handling during synthesis of peptide linkers or targeting modules, while the D-configuration supports stereochemical control over the conjugation point relative to the backbone. The benzyl-protected sulfur equivalent can be carried through linker construction and then converted into a reactive thiol or related sulfur functionality for coupling to maleimides, activated halides, or other electrophilic partners. Resulting sulfur-functional linkers and peptide conjugates can be used to produce defined biomolecule-modified constructs for labeling, affinity probes, and mechanistic studies of sulfur-dependent interactions.
4. Peptidomimetics And SAR Studies
Fmoc-D-Pen(Bzl)-OH is applied in peptidomimetic construction and structure-activity relationship studies where a penicillamine-like sulfur residue is used as a stereodefined scaffold element. The amino acid backbone provides a predictable geometry for incorporation into peptide analogs, while the side-chain sulfur protection strategy supports controlled introduction of sulfur functionality without disrupting coupling chemistry. The Fmoc-protected amine enables systematic variation of neighboring residues in analog libraries, allowing SAR workflows to evaluate how sulfur placement and stereochemistry influence molecular recognition properties. Downstream analog generation from this chiral amino acid intermediate supports fragment-based scaffold optimization and medicinal chemistry-adjacent synthesis of defined peptidomimetic series.
5. Pharmaceutical Intermediate Preparation
Fmoc-D-Pen(Bzl)-OH is relevant to pharmaceutical intermediate preparation where sulfur-containing chiral amino acid derivatives are required for manufacturing of peptide-based intermediates and processable building blocks. The combination of an Fmoc-protected N-terminus and a free carboxylic acid supports incorporation into protected peptide fragments under controlled synthetic conditions, aligning with industrially scalable peptide coupling logic. The Pen(Bzl) protection pattern helps manage sulfur reactivity during intermediate handling, supporting reproducible conversion to later-stage sulfur-functional materials. Generated intermediates derived from this amino acid derivative can feed into downstream synthesis of peptide fragments, conjugatable linkers, and stereochemically defined sulfur-bearing compounds used in applied chemical manufacturing contexts.
6. Analytical Research Standards
Fmoc-D-Pen(Bzl)-OH is used for analytical research and method development where a structurally defined, Fmoc-protected D-penicillamine derivative serves as a reference material for peptide and amino acid analysis. The presence of both an Fmoc tag and a benzyl-protected sulfur side-chain provides characteristic chromatographic and spectrometric behavior that can support identification and quantification of related protected amino acid species. The free carboxylic acid and protected amine enable formation of defined derivatives used in calibration workflows for peptide coupling monitoring and impurity profiling. Use of this chiral amino acid intermediate in analytical standards supports robust characterization of sulfur-containing peptide building blocks and their deprotected or transformed counterparts.
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