Propargyl-PEG1-COOtBu | CAS 488150-84-1

Propargyl-PEG1-COOtBu is a PEGylated propargyl ester designed for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry workflows. The reagent combines a terminal alkyne handle for efficient conjugation with a short, flexible PEG spacer that improves solubility and reduces steric constraints in bioconjugation and materials labeling. The tert-butyl ester provides a protected carboxylate functionality that can be used as a downstream functional group for coupling, surface immobilization, or further derivatization in research-grade probe and biomaterials development.

1. Biomolecule Conjugation

Propargyl-PEG1-COOtBu is commonly used to introduce a click-ready alkyne functionality onto PEGylated biomolecule scaffolds, enabling subsequent attachment of azide-bearing partners such as targeting ligands, affinity handles, or reporter tags. The PEG spacer helps maintain accessibility of the reactive site during labeling, which is particularly valuable when conjugating to proteins, peptides, or nucleic-acid-binding constructs where steric crowding can limit functionalization efficiency. In workflows for building modular conjugates, the protected carboxylate is often leveraged to control reactivity during intermediate steps, supporting clean downstream coupling strategies.

2. Surface And Hydrogel Functionalization

Propargyl-PEG1-COOtBu is frequently incorporated into surface modification and soft-material labeling processes where stable, addressable attachment points are required for subsequent click immobilization. The reagent’s terminal alkyne enables rapid coupling to azide-functional surfaces, coatings, or polymer networks, while the PEG component supports uniform presentation of functional groups and improved wetting in aqueous environments. The tert-butyl ester functionality is useful for preparing intermediate materials that can later be converted into carboxylate-bearing motifs for additional crosslinking, polymer chemistry, or affinity chemistry, supporting iterative design of functional hydrogels and biomaterial interfaces.

3. Molecular Imaging Probe Building

Propargyl-PEG1-COOtBu is used as a building block for constructing imaging and detection reagents that require orthogonal, modular assembly of reporter components through CuAAC. The propargyl handle provides a reliable conjugation handle for attaching azide-containing fluorophores, quencher moieties, or imaging-compatible tags, while the PEG linker supports solubility and reduces aggregation during probe formulation and handling. The protected carboxylate can be retained during probe assembly and then used as a handle for further derivatization, such as introducing additional reactive groups for scaffold attachment or adjusting physicochemical properties for probe libraries used in molecular imaging research.

4. Diagnostic Reagent Development

Propargyl-PEG1-COOtBu is well suited for developing diagnostic and assay reagents that rely on controlled, high-specificity conjugation of capture or reporting components via click chemistry. In assay development pipelines, the reagent is used to install an alkyne-bearing PEG spacer onto reagent platforms such as affinity ligands, polymer carriers, or bead-based systems, enabling efficient downstream coupling to azide-functional detection elements. The tert-butyl ester provides a protected carboxylate motif that supports stepwise assembly, allowing teams to manage intermediate reactivity while maintaining robust conjugation performance in automated labeling workflows and reagent kit preparation for research assays.