Azido-PEG4-4-nitrophenyl carbonate | CAS 1422540-98-4

Azido-PEG4-4-nitrophenyl carbonate is a PEG-based aryl carbonate click chemistry reagent that combines an azide handle with a nitrophenyl carbonate leaving group, enabling efficient conjugation workflows in chemical biology and materials science. The reagent’s flexible PEG4 spacer improves solubility and reduces steric constraints, while the azide functionality supports downstream strain-promoted or copper-catalyzed azide–alkyne cycloaddition for bioconjugation and labeling strategies. As a versatile “azide-installing” carbonate, it is commonly used to functionalize amine-containing biomolecules, surfaces, and polymeric scaffolds prior to attaching imaging tags, affinity ligands, or other modular components.

1. Amine-Targeted Bioconjugation

Azido-PEG4-4-nitrophenyl carbonate is widely used to introduce azide functionality onto amine-bearing biomolecules such as proteins, peptides, and antibody fragments during labeling and reagent preparation. The nitrophenyl carbonate motif reacts with nucleophilic amines under standard bioconjugation conditions, producing stable carbamate linkages that preserve the azide for subsequent click coupling. This approach is especially common in workflows that require controlled installation of clickable handles for later attachment of fluorophores, affinity tags, or other functional payloads, including when minimizing aggregation and maintaining aqueous compatibility are priorities.

2. Modular Probe Labeling

Azido-PEG4-4-nitrophenyl carbonate supports modular assembly of chemical probes by providing a convenient azide handle on a wide range of research reagents and carriers. After azide installation, the resulting clickable conjugates can be coupled to alkyne-bearing imaging dyes, biotin analogs, or other reporter groups using established click chemistry formats used across molecular imaging and diagnostic reagent development. The PEG4 spacer is frequently leveraged to improve labeling accessibility and reduce steric interference, which helps maintain strong reactivity of the azide in subsequent coupling steps and supports reproducible probe generation for assay development and analytical characterization.

3. Surface And Material Functionalization

Azido-PEG4-4-nitrophenyl carbonate is used to functionalize polymeric materials and material surfaces that present accessible amine groups, enabling the incorporation of azide sites for later click-based immobilization. Researchers employ this reagent to prepare clickable coatings, functional polymer networks, and derivatized nanoparticles where downstream attachment of ligands, crosslinkers, or imaging moieties is performed via azide–alkyne cycloaddition. The PEG4 linker contributes to improved hydration and spacing between the surface and the clickable group, which can be important for maintaining reactivity and for achieving uniform functional density across heterogeneous materials.

4. Affinity Ligand And Capture Reagents

Azido-PEG4-4-nitrophenyl carbonate is commonly applied to generate azide-functional affinity reagents used in pull-down, capture, and enrichment workflows in chemical biology. By installing azide groups onto amine-containing targeting components such as binding proteins, peptides, or polymeric affinity ligands, the reagent enables later conjugation to alkyne-functional surfaces, beads, or detection reporters through click coupling. This strategy is frequently adopted in diagnostic reagent development and analytical assay optimization because it allows modular swapping of capture formats and readout chemistries while keeping the azide handle consistent across reagent batches.