Boc-Asp(OSu)-OBzl is a protected amino acid derivative based on the aspartic acid scaffold, bearing an N-terminal Boc protecting group and a C-terminal benzyl ester (OBzl) while the side chain is converted to an activated N-hydroxysuccinimide ester (OSu). The molecule contains both an amino functionality masked as the Boc carbamate and a carboxyl functionality masked as an ester, with the side-chain carboxyl transformed into an OSu leaving group suitable for acyl transfer chemistry, and the stereochemical configuration is not specified in the name. In peptide and bioconjugation workflows, this structure is used as a precursor that combines protected backbone functionality for controlled coupling with a reactive activated ester handle for forming amide linkages to nucleophiles during synthesis or labeling.
CAT No: CP26365
CAS No:140171-25-1
Synonyms/Alias:BOC-ASP(OSU)-OBZL;140171-25-1;Boc-L-asparticacidbeta-N-hydroxysuccinimideesteralpha-benzylester;BOC-ASP-OBZL;SCHEMBL8059266;CTK8F0224;6280AH;ZINC71788034;RT-011756;K-4523
Boc-Asp(OSu)-OBzl is a protected aspartic acid derivative featuring a Boc-protected amino group and an activated side-chain carboxylate presented as an N-hydroxysuccinimide (OSu) ester, along with a benzyl ester on the α-carboxyl group. This combination makes the molecule a practical electrophilic amino acid building block for assembling aspartate-containing peptide segments and for generating aspartate-derived amide linkages under coupling conditions that favor OSu ester reactivity. The presence of orthogonally protected carboxyl functionality supports downstream conversion into defined peptide or intermediate architectures used in peptide chemistry and pharmaceutical intermediate development.
1. Peptide Segment Coupling
Boc-Asp(OSu)-OBzl is frequently used by peptide synthesis groups to introduce an aspartate residue in a protected form where the side-chain is already activated for rapid nucleophilic acylation. Researchers performing custom peptide assembly rely on the OSu ester to promote efficient coupling to amine-containing partners, enabling controlled formation of aspartate side-chain amide linkages during segment condensation or modified residue incorporation. The benzyl ester on the α-carboxyl group helps maintain the intended functional-group pattern through the coupling step, supporting selective downstream transformations when the peptide or peptidomimetic scaffold requires a specific protection scheme.
2. Aspartate-Derived Amide Linkers
Boc-Asp(OSu)-OBzl is used in medicinal chemistry and process development workflows where aspartate-based amide formation is required as a key bond-forming step in intermediate synthesis. In such applications, the OSu ester serves as a reactive handle that can be converted to an amide by reaction with an appropriate amine nucleophile, allowing chemists to build defined linkers or side-chain modifications without exposing the molecule to more aggressive activation strategies. The dual ester protection pattern (Boc on nitrogen and benzyl on the α-carboxyl) helps preserve chemoselectivity, which is valuable when the target intermediate must retain specific protected groups for later deprotection or further coupling.
3. Pharmaceutical Intermediate Building Blocks
Boc-Asp(OSu)-OBzl is commonly positioned as a specialized amino acid intermediate for preparing aspartate-containing small molecules and peptidomimetic structures during lead optimization and route scouting. Process chemists and synthetic development teams use the activated OSu functionality to streamline assembly of amide-containing fragments while keeping the backbone protected to reduce side reactions and improve reproducibility across batch preparations. This reagent form is particularly relevant when the downstream synthetic plan depends on staged deprotection and coupling, such as converting protected carboxyl groups at a later stage to access the desired intermediate for subsequent transformations.
4. Protected Aspartate Modification
Boc-Asp(OSu)-OBzl is also applied in research settings focused on installing aspartate-derived modifications onto larger scaffolds, including protected peptide fragments and custom building blocks used for structure-activity relationship studies. The OSu ester provides a convenient activation state for side-chain functionalization, while the Boc/benzyl protection pattern supports retention of the amino acid backbone identity through the modification step. Teams developing modified peptide analogs or aspartate-containing conjugation precursors often select this derivative because it offers a clear, controllable route to introduce an aspartate side-chain amide under conditions compatible with protected intermediate handling.
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