Click reactions are quantitative, rapid, have high efficiency, stereo selectivity, and few or no by-products under mild reaction conditions. The traditional click reaction refers to azide and 1,3-dipole ring addition reaction with the catalyst copper (I). As known, copper (I) is cytotoxic and it can damage red blood cells which makes the traditional click reaction limited in its use in biomedical applications.

As early as 1961, the publication “Zur Existenz Niedergliedriger Cycloalkine, I and II” mentioned the phenyl azide and cycloalkines reacting without the need for a copper (I) catalyst. However, most of the cyclooctyne reagents do not have good water solubility, which limits their applications in biomedicine.

JenKem Technology patented a series of polyethylene glycol-cyclooctyne derivatives which react with azide without copper(I) catalyst, thus making the post-processing very simple and eliminating the cytotoxicity issues of the traditional click chemistry. JenKem® PEG-cyclooctynes have good water solubility and biocompatibility. Polyethylene glycol derivatives are widely used in polypeptide, protein and drug delivery to prolong half-life, and reduce immunogenicity and toxicity; either in combination with a drug molecule via PEGylation, or as part of hydrogels.

Advantages of Novel PEG Cyclooctyne Derivatives for Click Chemistry:

  • React with azide without cytotoxic copper (I) catalyst
  • No cytotoxicity issues like those associated with traditional click chemistry
  • Good water solubility and biocompatibility
  • Applications in drug delivery to prolong half-life, and reduce drug immunogenicity and toxicity
  • Multiarm PEG-cyclooctynes available for hydrogel formation

These products are made to order, please contact us for details.

JenKem Technology also has extensive capability to provide high quality PEG Dibenzocyclooctyne products in large kilogram-scale, in both non-GMP and GMP grade, at affordable prices. Below are several examples of PEG DBCO products manufactured by JenKem Technology. PEG and monodisperse PEG DBCO derivatives with different branching, MW, and functionalities may be available by custom synthesis.

Methoxy PEG DBCO Products
Item Number Item Description
M-DBCO-2000 Methoxy PEG Dibenzocyclooctyne, MW 2000
M-DBCO-3500 Methoxy PEG Dibenzocyclooctyne, MW 3500
M-DBCO-5000 Methoxy PEG Dibenzocyclooctyne, MW 5000
M-DBCO-10K Methoxy PEG Dibenzocyclooctyne, MW 10000
M-DBCO-20K Methoxy PEG Dibenzocyclooctyne, MW 20000
M-DBCO-30K Methoxy PEG Dibenzocyclooctyne, MW 30000
M-DBCO-40K Methoxy PEG Dibenzocyclooctyne, MW 40000
Y-Shaped and U-Shaped PEG DBCO Products
Item Number Item Description
Y-DBCO-40K Y-shape (MPEG20K)2 Dibenzocyclooctyne, MW 40000
MPEG2-DBCO-40K MPEG2 Dibenzocyclooctyne, MW 40000
Homobifunctional PEG DBCO Products
Item Number Item Description
DBCO-PEG2000-DBCO PEG (Dibenzocyclooctyne)2, MW 2000
DBCO-PEG5000-DBCO PEG (Dibenzocyclooctyne)2, MW 5000
DBCO-PEG10K-DBCO PEG (Dibenzocyclooctyne)2, MW 10000
Multi-arm PEG DBCO Products
Item Number Item Description
4ARM-DBCO-10K 4arm PEG Dibenzocyclooctyne (pentaerythritol), MW 10000
4ARM-DBCO-20K 4arm PEG Dibenzocyclooctyne (pentaerythritol), MW 20000
8ARM(TP)-DBCO-10K 8arm PEG Dibenzocyclooctyne (tripentaerythritol), MW 10000
8ARM(TP)-DBCO-20K 8arm PEG Dibenzocyclooctyne (tripentaerythritol), MW 20000
8ARM(TP)-DBCO-40K 8arm PEG Dibenzocyclooctyne (tripentaerythritol), MW 40000
Heterobifunctional PEG DBCO Products
Item Number Item Description
DBCO-PEG2000-SCM Dibenzocyclooctyne PEG Succinimidyl Carboxymethyl Ester, MW 2000
DBCO-PEG3500-SCM Dibenzocyclooctyne PEG Succinimidyl Carboxymethyl Ester, MW 3500
DBCO-PEG5000-SCM Dibenzocyclooctyne PEG Succinimidyl Carboxymethyl Ester, MW 5000
DBCO-PEG2000-NH2 Dibenzocyclooctyne PEG Amine, Free amine, MW 2000
DBCO-PEG3500-NH2 Dibenzocyclooctyne PEG Amine, Free amine, MW 3500
DBCO-PEG5000-NH2 Dibenzocyclooctyne PEG Amine, Free amine, MW 5000
DBCO-PEG2000-MAL Dibenzocyclooctyne PEG Maleimide, MW 2000
DBCO-PEG3500-MAL Dibenzocyclooctyne PEG Maleimide, MW 3500
DBCO-PEG5000-MAL Dibenzocyclooctyne PEG Maleimide, MW 5000
DBCO-PEG2000-OH Dibenzocyclooctyne PEG Hydroxyl, MW 2000
DBCO-PEG3500-OH Dibenzocyclooctyne PEG Hydroxyl, MW 3500
DBCO-PEG5000-OH Dibenzocyclooctyne PEG Hydroxyl, MW 5000
DBCO-PEG2000-OPSS Dibenzocyclooctyne PEG OPSS, MW 2000
DBCO-PEG3500-OPSS Dibenzocyclooctyne PEG OPSS, MW 3500
DBCO-PEG5000-OPSS Dibenzocyclooctyne PEG OPSS, MW 5000
Monodisperse PEG DBCO Linkers for ADCs
Product Name Molecular Weight
DBCO-PEG2-PA 464.5
DBCO-PEG3-PA 508.6
DBCO-PEG4-PA 552.6
DBCO-PEG6-PA 640.7
DBCO-PEG8-PA 728.8
DBCO-PEG10-PA 816.9
DBCO-PEG12-PA 905.0
DBCO-PEG24-PA 1433.7
DBCO-PEG8-CM 714.8
DBCO-PEG12-CM 891.0
DBCO-PEG24-CM 1419.7
DBCO-PEG8-NH2 655.8
DBCO-PEG12-NH2 832.0
DBCO-PEG24-NH2 1360.6
DBCO-PEG12-VC-PAB 1266.5
DBCO-PEG24-VC-PAB 1795.1
DBCO-PEG12-VA-PAB 1180.4
DBCO-PEG24-VA-PAB 1709.0

JenKem Technology offers custom manufacture for other PEG products for copper-free click chemistry not listed here, please contact us with your custom requests.

Please contact us at for a quotation and more information about these PEG products for Copper-Free Click Chemistry.

JenKem Technology specializes in the development and manufacture of high-quality polyethylene glycol (PEG) derivatives, and related custom synthesis and PEGylation services. JenKem Technology is ISO 9001 and ISO 13485 certified and adheres to ICH Q7 guidelines for GMP manufacture. The production of JenKem® PEGs is back integrated to in-house polymerization from ethylene oxide to ensure batch to batch consistency. JenKem Technology caters to the PEGylation needs of the pharmaceutical, biotechnology, medical device and diagnostics, and emerging chemical specialty markets, from laboratory scale through large commercial scale.


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