Fmoc-Asp-OH is an Fmoc-protected amino acid derivative of aspartic acid, featuring a side-chain carboxylic acid that corresponds to the β-carboxyl functionality of Asp. The molecule contains an α-amino group and an α-carboxylic acid, with the amino functionality protected as the 9H-fluoren-9-ylmethoxycarbonyl (Fmoc) carbamate, which masks the amine to control chemoselectivity during peptide assembly. Fmoc-Asp-OH is used as a stepwise building block for peptide synthesis, including solid-phase peptide synthesis and related coupling strategies, where the free side-chain carboxyl group can be addressed for further derivatization or maintained for incorporation into peptide structures.
CAT No: CP26235
CAS No:119062-05-4
Synonyms/Alias:119062-05-4;Fmoc-Asp-OH;Fmoc-L-asparticacid;N-Fmoc-L-asparticAcid;Fmoc-L-Asp-OH;(S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)succinicacid;N-[(9H-Fluoren-9-ylmethoxy)carbonyl]-L-asparticAcid;(S)-2-(((9H-fluoren-9-yl)methoxy)carbonylamino)succinicacid;C19H17NO6;PubChem10004;FMOC-ASPARTICACID;SCHEMBL378041;CTK0H4677;KSDTXRUIZMTBNV-INIZCTEOSA-N;MolPort-003-986-289;ACT06845;ZINC2556456;ANW-17277;CF-170;AKOS015910142;AB05429;AM81590;RTR-003222;AC-17109;AJ-39905
Fmoc-Asp-OH is an N-(9H-fluoren-9-ylmethoxycarbonyl) protected L-aspartic acid bearing a free carboxylic acid at the side chain, providing an orthogonally addressable dicarboxylate functionality. The molecule contains an Fmoc carbamate that masks the α-amino group for base-labile protection during peptide assembly, while the β-carboxyl group remains available for selective activation, salt formation, or further side-chain protection. The stereogenic center at the α-carbon preserves the L-aspartate configuration, which is critical for predictable peptide backbone geometry and for downstream recognition in biochemical assays. The presence of two carboxylic acid groups yields strong hydrogen-bonding and acid-base behavior, making Fmoc-Asp-OH a practical chiral amino acid derivative for protected amino acid synthesis and peptide coupling workflows.
1. Peptide Synthesis
Fmoc-Asp-OH is used in peptide synthesis workflows where orthogonally protected aspartate residues must be incorporated with controlled N-terminal chemistry. The Fmoc carbamate protects the α-amino group during coupling cycles, while the side-chain carboxylic acid participates as a functional handle for aspartyl residue placement and subsequent derivatization. The dicarboxylate pattern supports standard peptide coupling strategies after activation of the α-carboxyl group, and the free β-carboxyl can be selectively protected or left available depending on the target sequence. The resulting aspartate-containing peptide fragments can be extended toward full-length constructs for research-grade libraries, sequence variants, and mechanistic studies in peptide science. Fmoc-Asp-OH thereby functions as a stereochemically defined, peptide-compatible building block for constructing aspartate-rich motifs.
2. Side-Chain Functionalization
Fmoc-Asp-OH is applied in amino acid derivatization and side-chain functionalization programs that require a protected backbone amine with an exposed β-carboxyl group. The side-chain carboxylic acid enables conversion into amides, esters, thioesters, or activated intermediates for attaching functional moieties that modulate charge, polarity, or binding interactions. The Fmoc group supports stepwise synthetic planning by allowing peptide coupling or fragment assembly before side-chain transformations, and it can be removed under base conditions to expose the α-amino group for subsequent chemistry. The stereodefined aspartate scaffold can be used to generate C-terminal or internal aspartate analogs that retain conformational preferences relevant to peptide mimetics and chemical biology probes. Downstream products can serve as intermediates for charged residue tuning, affinity tag development, and structure-guided optimization of peptide-based scaffolds.
3. Chemical Biology Probes
Fmoc-Asp-OH is suitable for chemical biology research where aspartate residues are incorporated into labeled peptides, activity probes, or recognition elements that depend on acidic side-chain chemistry. The free β-carboxyl group provides a handle for conjugation to linkers, fluorophores, biotin-like tags, or affinity reagents through amide or ester bond formation after appropriate activation. The Fmoc-protected α-amino group enables controlled assembly of probe sequences on solid-phase or in fragment condensation strategies, supporting consistent incorporation of L-aspartate stereochemistry. The resulting labeled or conjugatable peptide constructs can be used to interrogate binding interfaces, substrate preferences, or residue-level determinants in biochemical assays. Fmoc-Asp-OH thus serves as a protected amino acid intermediate that bridges peptide construction with downstream biomolecule labeling chemistry.
4. Protein Engineering and SAR Studies
Fmoc-Asp-OH is employed in protein engineering and structure-activity relationship studies that require defined incorporation of acidic residues into peptide mimics or protein-interacting domains. The L-aspartate side chain contributes a negatively charged carboxylate that can influence local electrostatics, hydrogen-bond networks, and conformational stabilization in designed sequences. The Fmoc protection strategy supports systematic generation of peptide variants where the α-amino group is masked during assembly and later revealed for controlled coupling or extension, enabling reproducible residue substitution patterns. The β-carboxyl group can be maintained for charge-preserving analogs or transformed into modified carboxylate derivatives to probe recognition mechanisms. Fmoc-Asp-OH therefore supports residue-level SAR mapping and engineering of sequence-defined constructs for applied biochemical research.
5. Pharmaceutical Intermediate Preparation
Fmoc-Asp-OH is applied in pharmaceutical intermediate preparation where protected amino acid chemistry is used to build peptide-based or peptide-derived active ingredients and their synthetic precursors. The Fmoc carbamate provides a robust N-protection scheme compatible with common peptide coupling conditions, while the free side-chain carboxylic acid enables downstream functionalization needed for prodrug-like modifications, solubility tuning, or linker installation. The dicarboxylate motif can be used to generate activated aspartate derivatives that feed into larger fragment condensations, including C-terminal modifications and side-chain conjugation steps. The stereochemical integrity of the L-aspartate center supports predictable incorporation into chiral peptide architectures used in fine chemical manufacturing. Fmoc-Asp-OH thereby functions as a process-relevant, peptide-compatible intermediate for producing aspartate-containing building blocks used in industrial synthesis routes.
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