H-L-Dap(Fmoc)-OtBu*HCl is an Fmoc-protected derivative of Dap (2,3-diaminopropanoic acid/2,3-diaminopropionic acid) bearing a tert-butyl ester on the carboxyl group, supplied as the hydrochloride salt. The molecule contains an Fmoc carbamate on the amino functionality, a tert-butyl ester (OtBu) for carboxyl protection, and two amino groups on the side chain characteristic of Dap, with stereochemistry indicated as D at the α-carbon and the "*HCl" reflecting salt formation. In peptide synthesis workflows, the orthogonal protection pattern (Fmoc on nitrogen and OtBu on the carboxyl) supports stepwise assembly of peptide chains by controlling chemoselectivity of coupling and subsequent deprotection steps, while the salt form can improve handling and solubility for solid-phase or solution-phase preparation of Dap-containing peptide intermediates.
CAT No: CP25720
CAS No:291529-78-7
Chemical Name:N-beta-(9-Fluorenylmethyloxycarbonyl)-L-2,3-diaminopropionic acid t-butyl ester hydrochloride
H-L-Dap(Fmoc)-OtBu*HCl is a protected L-2,3-diaminopropanoic acid derivative in which the α-amino group is masked as an Fmoc carbamate and the carboxyl group is esterified as an OtBu group, with the hydrochloride salt form improving handling of the basic diamine functionality. The molecule retains the stereodefined amino acid backbone while presenting a second, unprotected side-chain amino group that can be selectively functionalized after orthogonal deprotection. The Fmoc group supports base-labile removal under standard peptide-synthesis conditions, while the tert-butyl ester can be cleaved under acid to reveal the free carboxylic acid for further coupling or for conversion into alternative protected forms. The combination of orthogonal protecting groups and a chiral center makes the compound a practical chiral amino acid intermediate for peptide building-block preparation and downstream derivatization workflows.
1. Peptide Synthesis
H-L-Dap(Fmoc)-OtBu*HCl is used in peptide synthesis workflows where Fmoc-based solid-phase or solution-phase strategies require a stable N-protected amino acid building block. The Fmoc carbamate protects the α-amino group during coupling cycles, while the tert-butyl ester masks the carboxyl functionality until deprotection steps are applied to set the correct coupling state. The side-chain amino group enables incorporation of Dap-containing motifs that can later be converted into urea, amide, sulfonamide, or protected guanidinium-like functionalities depending on the chosen derivatization chemistry. Peptide analog construction and fragment assembly benefit from the stereodefined backbone and orthogonal protecting-group logic that supports controlled peptide coupling chemistry and subsequent functional diversification.
2. Side-Chain Functionalization
H-L-Dap(Fmoc)-OtBu*HCl serves as a side-chain functionalization intermediate for generating amino acid derivatives with targeted reactivity at the free diamine position. The unmasked side-chain amine can undergo selective protection, acylation, sulfonylation, or formation of heterocycles after appropriate orthogonal deprotection of the carboxyl ester and/or modification of the Fmoc group. The Fmoc handle can be removed when the intermediate is transferred into a peptide or conjugation sequence, enabling staged introduction of functional groups without disturbing the stereochemical configuration. Downstream products include protected Dap derivatives for chemical biology probes, crosslinking reagents, and peptidomimetic scaffolds where side-chain chemistry governs binding and reactivity.
3. Protected Amino Acids
H-L-Dap(Fmoc)-OtBu*HCl is suitable for protected amino acid chemistry and chiral intermediate preparation where orthogonal protecting groups are required to manage multiple nucleophilic sites. The Fmoc carbamate and OtBu ester provide distinct deprotection regimes, allowing the synthesis route to switch between N-protected peptide building blocks and carboxyl-unmasked coupling partners as the sequence design evolves. The hydrochloride salt form supports reproducible handling of the basic diamine during derivatization and purification steps, which can be relevant for process chemistry intermediate preparation. The compound can be converted into alternative protected amino acid forms, enabling controlled C-terminal modification, amino acid ester synthesis, and preparation of defined stereochemical intermediates for fine chemical synthesis.
4. Chemical Biology Probes
H-L-Dap(Fmoc)-OtBu*HCl can be applied in chemical biology research for constructing labeled peptides and reactive amino acid motifs that rely on diamine chemistry. The protected amino acid framework supports incorporation into peptide constructs, while the side-chain amino group provides a handle for conjugation strategies such as attachment of acyl-linked labels, affinity tags, or linkers designed for downstream bioconjugation. The orthogonal protecting groups enable sequential unveiling of functional groups so that labeling can be performed at a defined stage without uncontrolled side reactions. Molecular probes and biochemical research intermediates generated from this compound can support studies of molecular recognition, binding-site mapping, and structure-guided scaffold modification using stereochemically defined amino acid building blocks.
5. Pharmaceutical Manufacturing
H-L-Dap(Fmoc)-OtBu*HCl is relevant to pharmaceutical manufacturing and process chemistry intermediate preparation for peptide and peptidomimetic production where reproducible protected amino acid handling is required. The Fmoc-protected α-amino group and tert-butyl ester provide a protected form that can be integrated into controlled coupling sequences, supporting manufacturing-oriented route design that minimizes premature functional-group exposure. The diamine side chain can be managed through protection and selective deprotection strategies to meet intermediate specifications for subsequent synthesis steps and purification compatibility. Industrial workflows that generate peptide intermediates, defined amino acid derivatives, and functionalized coupling partners can employ this compound as a stereodefined chiral building block aligned with scalable amino acid derivative synthesis practices.
6. Peptidomimetics And SAR
H-L-Dap(Fmoc)-OtBu*HCl is suitable for peptidomimetic construction and SAR studies where Dap-containing motifs influence conformational preferences and interaction patterns. The stereodefined amino acid backbone and protected functional groups enable systematic variation of side-chain chemistry by converting the diamine into protected or substituted derivatives that modulate hydrogen-bonding and electrostatic character. Fmoc deprotection compatibility supports iterative scaffold assembly, while tert-butyl ester management supports controlled conversion into coupling-ready forms for analog generation. Structure-activity relationship studies can leverage the compound as a chiral amino acid intermediate to build libraries of functionalized peptide analogs and chemically defined fragments for downstream molecular design and analytical characterization workflows.
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