Br-PEG4-COOtBu
CAS No.: 564476-32-0
Cat No.: BP-500353
Purity: ≥95%
4.5 
Br-PEG4-COOtBu is a bromide-terminated polyethylene glycol linker bearing a carboxylate protected as a tert-butyl ester, providing a chemically versatile scaffold for PROTAC and related targeted protein degradation constructs. Structurally, it combines a short PEG chain that confers aqueous solubility and conformational flexibility with a terminal alkyl bromide handle for nucleophilic substitution and a protected carboxyl group suitable for later deprotection or coupling. In PROTAC design, such linkers are used to spatially tune the relative positioning of the target-binding ligand and the E3 ligase recruiter, reducing steric clashes and improving productive ternary complex formation. The bromide functionality enables efficient attachment to nucleophilic moieties (e.g., amines or thiols) under standard synthetic conditions, while the ester protection supports controlled downstream functionalization. This product is valuable for rapid linker screening and for constructing modular degradation reagents where solubility and linker length are critical experimental variables.
Structure of 564476-32-0
Assurance
Delivery
Support
* For research and manufacturing use only. Not for human or clinical use.
| Size | Price | Stock | Quantity |
|---|---|---|---|
| -- | $-- | In stock |
Looking for different specifications? Click to request a custom quote!
Capabilities & Facilities
- Comprehensive PROTAC Platform
- Scientific Expertise & Technical Support
- Custom Synthesis & Design Service
- Extensive Product Coverage
- Cutting-Edge Innovation
- Fast Delivery & Global Support
- 24/7 customer service
- 100% quality assurance
Popular Publications Citing BOC Sciences Products
This Br-PEG4-COOtBu linker is designed for constructing PROTACs that require a reliable handle for conjugation and controlled spatial presentation between the target-binding ligand and the E3-ligase recruiter. Its PEG-based segment supports favorable solubility and reduced steric congestion, while the bromide and protected carboxyl functionality enable modular synthesis. The following sections describe its structure and the practical reactivity considerations for PROTAC assembly.
Structure: The linker contains a poly(ethylene glycol) ether chain terminated by a bromine substituent and a tert-butyl-protected carboxyl group. It features ether linkages along the PEG backbone, an alkyl bromide electrophile, and a carboxylate protected as a tert-butyl ester. These functionalities provide both polarity and orthogonal reactivity.
Reactivity: The bromide can participate in nucleophilic substitution reactions with suitable nucleophiles under standard organic conditions, enabling installation of one PROTAC fragment. The tert-butyl ester is typically used as a protected carboxyl group, which can be deprotected under acid conditions to reveal a reactive carboxylic acid for amide or ester coupling. Common coupling strategies for PROTAC linkages include carbodiimide-mediated amide formation, with compatible bases and activators in polar aprotic solvents.
* Our calculator is based on the following equation:
Concentration (start) x Volume (start) = Concentration (final) x Volume (final)
It is commonly abbreviated as: C1V1 = C2V2
Related Product Recommendations
Please contact us with any specific requirements and we will get back to you as soon as possible.
