N-(Azido-PEG2)-N-Boc-PEG3-acid | CAS 2086689-01-0

N-(Azido-PEG2)-N-Boc-PEG3-acid is a PEGylated azide-bearing building block designed for bioorthogonal click chemistry workflows, most commonly serving as an azide partner for strain-promoted or copper-catalyzed azide–alkyne cycloaddition. The reagent combines an azide functional group with flexible PEG spacers and a protected amine handle (Boc) alongside a carboxylic acid for conjugation and surface/material coupling. Its water-compatible polyethylene glycol architecture makes it well suited for constructing soluble bioconjugates, imaging probes, and functional biomaterials where steric spacing and improved conjugation control are important.

1. Protein And Peptide Conjugation

N-(Azido-PEG2)-N-Boc-PEG3-acid is widely used to introduce an azide functionality into protein and peptide conjugation schemes, enabling subsequent attachment to alkyne-functional partners through click chemistry. The carboxylic acid supports coupling strategies for installing the PEG-azide tag onto biomolecules or onto activated linkers used downstream in labeling workflows. PEG2/PEG3 spacing helps mitigate steric constraints that can otherwise reduce labeling efficiency or alter biomolecular behavior, which is particularly valuable in affinity reagents and molecular imaging constructs.

2. Surface Functionalization For Biosensors

N-(Azido-PEG2)-N-Boc-PEG3-acid is applicable to the preparation of azide-functional surfaces used in biosensor development and analytical assay platforms that rely on modular click-based immobilization. The presence of a carboxylic acid enables attachment to polymeric supports, linker chemistries, or pre-activated surface coatings, while the azide provides a stable handle for later coupling to alkyne-bearing capture molecules or reporter tags. PEG spacers promote more uniform presentation of the reactive handle and can improve accessibility of immobilized ligands, supporting robust assay reagent assembly and reproducible surface chemistry.

3. Molecular Imaging Probe Assembly

N-(Azido-PEG2)-N-Boc-PEG3-acid is commonly incorporated into molecular imaging probe pipelines to build azide-functional intermediates that can be clicked to fluorescent dyes, radiolabeling chelators, or other imaging reporters bearing alkyne groups. The reagent’s PEG architecture supports improved solubility and reduced nonspecific interactions in labeling workflows, which is advantageous when generating conjugates intended for sensitive detection readouts in research settings. The Boc-protected amine and carboxylate functionality also provide additional orthogonal handles for tailoring probe format prior to final reporter installation.

4. PEG-Linker For Drug Discovery Tools

N-(Azido-PEG2)-N-Boc-PEG3-acid is used as a PEG-based click handle in medicinal chemistry and chemical biology tool development, where modular assembly of probes, affinity reagents, and mechanistic tags benefits from azide–alkyne conjugation. Researchers employ the carboxylic acid for incorporation into linker systems and the azide group for late-stage attachment of functional moieties, allowing rapid iteration of probe architectures without redesigning the entire scaffold. The flexible PEG spacers help tune effective linker length and reduce steric interference between the conjugated components, supporting consistent performance across libraries of research reagents.