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Azido-dPEG®₄-TFP ester (QBD-10567)



Azido-dPEG®4-TFP ester, product number QBD-10567, is a crosslinking compound designed for copper(I)-catalyzed, ruthenium catalyzed, and strain promoted click chemistry (CuAAC, RuAAC, and SPAAC, respectively). The two ends of the molecule are separated by a short (16 atoms), single molecular weight, discrete polyethylene glycol (dPEG®) spacer. The spacer imparts water solubility to QBD-10567 and increases the hydrodynamic volume of the conjugate molecule. The azide group provides the click chemistry functionality, while the 2,3,5,6-tetrafluorophenyl (TFP) ester reacts primary and secondary amines. The single molecular weight and discrete chain length of the spacer simplifies analysis of the product and of its conjugates.

TFP esters are an alternative to the widely popular N-hydroxysuccinimidyl (NHS) esters. TFP esters are more hydrolytically stable than NHS esters, and their optimal reaction pH range (7.5 – 8.0) is somewhat higher than NHS esters (7.0 – 7.5). Moreover, TFP esters in their optimal pH range are more reactive toward free amines than NHS esters.


Unit Size100mg, 1000mg
Molecular Weight439.36; single compound
Chemical formulaC₁₇H₂₁F₄N₃O₆
Purity> 98%
dPEG® Spacer is 16 atoms and 17.7 Å
Typical solubility properties (for additional information contact Customer Support)Methylene Chloride, DMSO, THF, Ethyl Acetate, Methanol or Acetonitrile.
Storage and handling-20°C; Always let come to room temperature before opening; be careful to limit exposure to moisture and restore under an inert atmosphere; stock solutions can be prepared with dry solvent and kept for several days (freeze when not in use). dPEG® pegylation compounds are generally hygroscopic and should be treated as such. This will be less noticeable with liquids, but the solids will become tacky and difficult to manipulate, if care is not taken to minimize air exposure.


Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0). Specifically see pp. 726-729 in his Chapter 18 on discrete PEG compounds for pegylation applications.

Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See chapter 18, Discrete PEG Reagents, pp.787-821, for a full overview of the dPEG® products.

Applicable patents and legal notices are available at legal notices.

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