Fmoc-D-Asp(2-phenylisopropyl ester)-OH is a protected, non-natural amino acid derivative of D-aspartic acid in which the side-chain carboxyl group is esterified with a 2-phenylisopropyl (Pip) group and the α-amino functionality is masked as an Fmoc carbamate. The molecule therefore contains an Fmoc-protected amine and a free α-carboxylic acid (-COOH), while the side-chain bears an esterified carboxyl that is less prone to undesired acylation or salt formation during peptide assembly. In peptide chemistry and chemical biology, this structure is used as a stepwise building block for solid-phase or solution-phase synthesis to control chemoselectivity by orthogonally protecting the side-chain carboxyl while maintaining the α-functional groups required for amide bond formation.
CAT No: CP26787
CAS No:214852-39-8
Synonyms/Alias:214852-39-8;Fmoc-D-Asp(OPp)-OH;FMOC-D-ASP-OH
Fmoc-D-Asp(2-phenylisopropyl ester)-OH is an Fmoc-protected D-aspartic acid derivative in which the side-chain carboxyl group is masked as a 2-phenylisopropyl ester, while the alpha-amino functionality is protected to support orthogonal peptide assembly. The molecule contains a stereogenic center at the D-aspartate backbone, a carboxylic acid at the alpha position, and an aromatic-rich side-chain ester that modulates polarity and influences coupling and deprotection behavior. The Fmoc group enables base-mediated removal during solid-phase peptide synthesis, whereas the 2-phenylisopropyl ester can be designed for selective side-chain unmasking under conditions compatible with peptide-bound intermediates. The combination of an orthogonally protected amino acid framework and a chiral esterified side chain makes the compound a practical chiral building block for constructing aspartate-containing sequences and for downstream derivatization of the side-chain carboxyl functionality.
1. Protected Amino Acid Chemistry
Fmoc-D-Asp(2-phenylisopropyl ester)-OH supports protected amino acid synthesis workflows where orthogonal handling of the alpha-amino and side-chain carboxyl groups is required. The Fmoc-protected amine participates in standard peptide coupling chemistry after deprotection, while the side-chain 2-phenylisopropyl ester provides a controlled masking strategy for the aspartate carboxyl during assembly. The D-configuration at the backbone stereocenter enables stereochemically defined incorporation into peptide chains and can be critical for producing D-amino acid rich analogs used in stereochemical studies. The esterified side chain can be unmasked to regenerate an aspartate carboxyl for subsequent functional transformations, making the compound suitable for iterative amino acid derivatization and protected intermediate preparation.
2. Peptide Synthesis
Fmoc-D-Asp(2-phenylisopropyl ester)-OH is used as a peptide building block in solid-phase and solution-phase peptide synthesis targeting aspartate side-chain control. The Fmoc group enables iterative N-terminal deprotection and coupling cycles, while the side-chain ester reduces undesired side reactions by preventing premature carboxyl reactivity during chain elongation. The aromatic 2-phenylisopropyl ester can be selected to balance stability during synthesis with later side-chain deprotection, allowing controlled generation of free aspartate functionality for cyclization, salt formation, or further side-chain modification. The D-aspartate stereochemistry supports preparation of stereochemically defined peptide analogs for structure-activity relationship studies and for tuning peptide conformation.
3. Peptidomimetics And SAR
Fmoc-D-Asp(2-phenylisopropyl ester)-OH serves in peptidomimetic and SAR-oriented molecular design where aspartate side-chain geometry and carboxyl availability govern receptor or target binding motifs. The protected side-chain carboxyl allows incorporation into analog libraries without uncontrolled crosslinking or intramolecular side reactions, while later ester removal can reveal a functional acid for salt-bridge formation or for conversion to amides, esters, or other carboxyl derivatives. The D-configuration can alter backbone orientation and hydrogen-bonding patterns relative to L-aspartate, supporting stereochemical exploration of binding determinants. The Fmoc-enabled assembly into defined sequences also supports rapid generation of analogs for downstream analytical characterization and comparative SAR mapping.
4. Chemical Biology Conjugation
Fmoc-D-Asp(2-phenylisopropyl ester)-OH can be applied in chemical biology workflows that require controlled presentation of an aspartate carboxyl for conjugation chemistry. The side-chain ester masking helps maintain compatibility with peptide synthesis and purification steps, while the later regeneration of the carboxyl group enables coupling to amines, alcohols, or linkers through standard carboxyl activation strategies. The aromatic-rich ester group can influence solubility and handling during intermediate preparation, which may be relevant for preparing conjugatable peptide fragments or labeled biomolecule building blocks. The D-aspartate backbone can be incorporated into labeling peptides or affinity probes where stereochemistry affects protease stability and recognition by binding partners.
5. Pharmaceutical Intermediate Preparation
Fmoc-D-Asp(2-phenylisopropyl ester)-OH is suitable for pharmaceutical intermediate preparation in fine chemical manufacturing routes that synthesize protected amino acid fragments for peptide-like active ingredients. The orthogonal protection pattern, combining Fmoc for N-terminal deprotection with a side-chain ester that can be unmasked without disturbing the peptide-ready amine framework, supports scalable intermediate handling and predictable downstream transformations. The presence of a defined chiral center helps ensure stereochemical fidelity when producing D-aspartate-containing intermediates used in drug discovery chemistry and process development. The compound can be carried through as a controlled functional group precursor to generate free aspartate derivatives, enabling downstream formation of amide-linked motifs, salt forms, or further functionalization steps required in industrial synthesis planning.
6. Process Chemistry And Specialty Synthesis
Fmoc-D-Asp(2-phenylisopropyl ester)-OH aligns with process chemistry needs for robust protected amino acid intermediates used in specialty chemical production. The Fmoc-protected amine supports standard coupling/deprotection cycles, while the 2-phenylisopropyl ester provides a side-chain protection mode that can be tuned for selective unmasking, supporting streamlined manufacturing of aspartate-functionalized intermediates. The aromatic ester substituent can improve crystallinity or influence phase behavior during workup and purification, which may be leveraged when designing reproducible synthetic operations. The chiral D-aspartate framework and orthogonal functional group protection make the compound a practical input for producing stereodefined peptide fragments, peptidomimetic scaffolds, and downstream carboxyl-functional building blocks for industrial-scale organic synthesis.
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