Propargyl-PEG4-t-butyl ester | CAS 1355197-66-8

Propargyl-PEG4-t-butyl ester is a PEG-based propargylated ester designed for copper-free and copper-mediated click chemistry workflows, enabling efficient attachment of alkynyl handles to biomolecules, polymers, and surfaces. The reagent combines a flexible PEG4 spacer with a t-butyl ester motif that is commonly used to introduce a protected functional group while maintaining solubility and minimizing nonspecific interactions. As a result, Propargyl-PEG4-t-butyl ester is frequently selected as a modular linker precursor for downstream conjugation, surface functionalization, and probe construction in chemical biology and biomaterials research.

1. Biomolecule Conjugation

Propargyl-PEG4-t-butyl ester is widely used to install an alkynyl functional handle onto biomolecular scaffolds where PEG spacing is advantageous for preserving binding-site accessibility and reducing steric crowding. Researchers incorporate the PEG4-propargyl motif to generate clickable conjugates for labeling workflows, including attachment to peptides, proteins, and nucleic-acid-associated constructs. The t-butyl ester functionality supports practical intermediate handling, allowing teams to prepare reactive conjugates that can be carried forward into subsequent CuAAC or strain-promoted click coupling steps used for imaging and analytical reagent development.

2. Surface and Material Functionalization

Propargyl-PEG4-t-butyl ester is commonly applied in biomaterials and polymer science to introduce clickable PEG linkers onto material interfaces, enabling controlled immobilization of bioactive ligands, affinity tags, and detection reagents. The PEG4 spacer helps improve surface wettability and reduces nonspecific adsorption, which is important when functionalized substrates are used for assay development, biosensing platforms, and microscopy sample preparation. By providing a stable alkynyl handle, Propargyl-PEG4-t-butyl ester supports modular assembly of multilayer coatings and patterned surfaces through subsequent click-based coupling to complementary azide or cyclooctyne partners.

3. Molecular Imaging Probe Building

Propargyl-PEG4-t-butyl ester is used as a versatile intermediate for constructing imaging and tracking probes that require a robust, externally addressable click handle. Chemical biology groups employ the PEG4-propargyl architecture to connect reporter components, targeting motifs, or scaffold carriers while maintaining favorable solubility and reducing aggregation during probe formulation and handling. The reagent’s propargyl functionality enables rapid, orthogonal conjugation to azide-bearing fluorophores or other imaging reporters, supporting efficient generation of probe libraries for method development and instrument-ready sample preparation.

4. Diagnostic Reagent Development

Propargyl-PEG4-t-butyl ester is frequently incorporated into diagnostic reagent pipelines where clickable linkers are required to build consistent reagent architectures for downstream assay assembly. Teams use the PEG4 spacer to improve reagent stability in aqueous buffers and to tune the spacing between recognition elements and signaling components, which is valuable for reproducible conjugate performance in assay development workflows. The alkynyl handle introduced by Propargyl-PEG4-t-butyl ester allows straightforward coupling to azide-functional reporters, enabling scalable preparation of labeled reagents used in research diagnostics and analytical tool development.