• CAS No.：
  201467-81-4
• Synonyms：
  Azide-PEG4-CH2COOH
  14-Azido-3,6,9,12-tetraoxatetradecanoic acid
  14-Azido-3,6,9,12-tetraoxa-1-tetradecanoic acid
  2-[2-[2-[2-(2-azidoethoxy)ethoxy]ethoxy]ethoxy]ethanoic acid
  N3-TEG-COOH
  
• Purity：
  ≥95%
• MF：
  C₁₀H₁₉N₃O₆
• MW：
  277.27
• Recommended Storage Condition：
  Store at -5°C,keep in dry and avoid sunlight.
• Uses：
  Applicated in medical research, drug-release, nanotechnology and new materials research, cell culture. In the study of ligand, polypeptide synthesis support, a graft polymer compounds, new materials, and polyethylene glycol-modified functional coatings and other aspects of the active compound.

Monodisperse Azido-PEG4-CH2COOH (N3-PEG4-CH2COOH) is a very popular click chemistry linker containing an azide (N3) group with a terminal carboxylic acid (CH2COOH). The hydrophilic PEG spacer increases solubility in aqueous media. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU).

It is also a PROTAC linker containing four polyethylene glycol (PEG) units. 

References:
​[1]. Zengerle M, et al. Selective Small Molecule Induced Degradation of the BET Bromodomain Protein BRD4. ACS Chem Biol. 2015 Aug 21;10(8):1770-7.