Boc-D-Asn-ONp is a Boc-protected, D-configured amino acid derivative of asparagine in which the carboxyl group is converted to an ONp ester (N-hydroxysuccinimide ester), while the α-amino group is protected as a tert-butoxycarbonyl (Boc) carbamate. The molecule contains an amide side chain characteristic of asparagine, and its free functional groups are the Boc-protected nitrogen and the activated ONp ester, which can undergo acyl transfer chemistry under appropriate conditions to form amide linkages. Boc-D-Asn-ONp is used as a stepwise peptide-synthesis and bioconjugation building block, supporting controlled coupling of the asparagine residue or as an activated carboxyl equivalent for preparing amino-acid and peptide derivatives.
CAT No: CP26152
CAS No:104199-82-8
Synonyms/Alias:Boc-D-Asn-ONp;104199-82-8;Boc-D-asparagine4-nitrophenylester;Nalpha-Boc-D-asparagine4-nitrophenylester;4-nitrophenyln2-(tert-butoxycarbonyl)-d-asparaginate;AmbotzBAA5400;AC1Q60ZU;AC1L2V03;L-Asparagine,N2-((1,1-dimethylethoxy)carbonyl)-,4-nitrophenylester;CTK8E6097;MolPort-008-267-463;ZINC2155203;AR-1G4089;AM005851;DB-040524;RT-014647;I14-34037;N2-((1,1-Dimethylethoxy)carbonyl)-L-asparagine,4-nitrophenylester;(4-nitrophenyl)(2R)-4-amino-2-[(2-methylpropan-2-yl)oxycarbonylamino]-4-oxobutanoate;4-NITROPHENYL(2R)-2-[(TERT-BUTOXYCARBONYL)AMINO]-3-CARBAMOYLPROPANOATE;292870-05-4;51536-80-2
Boc-D-Asn-ONp is a Boc-protected D-asparagine derivative featuring an activated ONp ester (p-nitrophenyl ester) at the carboxylate position, making it a practical amino-acid building block for peptide coupling workflows that require high reactivity. The D-configuration provides stereochemical control for incorporating non-proteinogenic stereocenters into peptide segments, while the Boc group supports standard amine protection strategies during stepwise assembly. This reagent form is frequently selected in custom peptide synthesis and intermediate preparation where robust segment condensation and controlled coupling selectivity are required.
1. Peptide Segment Coupling
Boc-D-Asn-ONp is used by peptide synthesis groups to introduce a D-asparagine residue into peptide segments via activated ester coupling, helping streamline assembly of non-standard peptide backbones and stereodefined sequences. Researchers developing D-amino-acid-containing peptides for structure-activity relationship studies, protease-stability benchmarking, or conformational investigations often prefer ONp-activated amino acid derivatives because they offer a direct route to amide bond formation under commonly used peptide coupling conditions. The Boc-protected amine further supports compatibility with protected-peptide fragment strategies, enabling controlled stepwise synthesis rather than late-stage functionalization.
2. Stereodefined Peptidomimetic Building
Boc-D-Asn-ONp supports medicinal chemistry and chemical biology programs that require stereochemically defined peptidomimetics, including peptides designed to probe backbone stereochemistry effects and side-chain orientation in binding or recognition assays. Incorporation of a D-asparagine unit can be used to generate stereochemically discrete analogs for SAR workflows, where maintaining a consistent protected backbone while varying stereocenters is essential for interpretable structure-property comparisons. The activated ONp ester format is particularly useful when assembling longer or more complex sequences that benefit from reliable coupling performance at the amino-acid segment level.
3. Pharmaceutical Intermediate Development
Boc-D-Asn-ONp is also applied in the preparation of peptide-based pharmaceutical intermediates where a protected, activated amino acid is required as a defined input for downstream manufacturing of peptide intermediates and protected fragments. Process development teams and custom synthesis providers commonly select ONp-activated amino acid derivatives to reduce variability in coupling efficiency between batches and to support reproducible fragment condensation steps. The combination of Boc protection with an activated carboxylate enables controlled handling of the building block through intermediate stages, supporting consistent downstream assembly into larger protected peptide constructs.
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