(eq)HO-(exo)sTCO-COOEt (non-releasing)

Product information

• Function

  Strained Trans-Cyclooctene(TCO) – tetrazine click chemistry can be used for in vivo conjugation of two payloads with exceptionally fast reaction rates. The functional handle on the allylic position of the E-double bond can be charged with a payload that is released after conjugation with a tetrazine. In addition, this releasing-sTCO can selectively be functionalized due to the two orthogonal handles; a carboxylic group and a secondary alcohol group.

   

  A click reaction can be employed for bioconjugations, immobilization, in vivo staining and/or in vivo fluorescent labeling in combination with payload release (e.g. drug delivery).

• Mode of action

  The reaction of tetrazines with trans-cyclooctenes (TCOs) covalently binds the two molecules without interfering with the endogenous processes in living systems.¹ The reactions of TCOs with tetrazines have exceptionally fast reaction rates of up to 3.300.000 M^–1s^–1 depending on the TCO structure.² These properties make TCO click-chemistry a powerful tool for in vivo conjugations. Both the tetrazine and TCO can be charged with a payload (e.g. marker, antibodies, drugs) that can be joined in vivo.

   

  The second order rate constants for this product (exo)-sTCO-OH-COOEt are shown in the figure below. These second-order rate constants for reaction of TCO with 1.0 eq dipyridyltetrazine and dimethyltetrazine were determined using UV/Vis spectroscopy at 540 nm (specific for tetrazine) in acetonitrile at 21 °C.³

   

  This product forms a stable conjugate after reacting with tetrazines. The moiety on the allylic position does not eliminate after tautomerization. This was demonstrated by Sondag et. al. with the reaction of a PFP carbonate TCO-derivative and dipyridyltetrazine in chloroform by ¹⁹F-NMR. ³

  Alternatively, the axial isomer of this product has tetrazine mediated release capabilities. The product with tetrazine mediated can be found on this page.

• Applications

  The application of trans-cyclooctene (TCO) based click chemistry varies from synthesis of nanomaterials to labeling and drug delivery strategies.⁴⁵ The combination of TCO click chemistry with labeling dyes, radioactive isotopes, quantum dots or biomolecules such as proteins or nucleotides are already being explored.⁶⁷⁸⁹¹⁰ In preclinical studies of Positron Emission Tomography (PET) imaging with in vivo pretargeting, antibody-drug conjugates (ADCs) were successfully used for site-specific delivery of a radioactive cargo in mice.¹¹¹²

• Handling

  TCOs are sensitive to light. The product and reactions with the product should be shielded from light.

• Biological Activity

  TCOs have been used in cell cultures and mice for both imaging and therapy uses.¹³¹⁴¹⁵

• Chemical Information

  CAS No.: n/a
  SMILES: [H][C@@]12[C@@]([C@@H]2C(OCC)=O)([H])C/C([H])=C([H])/[C@@H](O)CC1
  Chemical formula: C₁₂H₁₈O₃
  Molecular weight: 210.27
  Purity: > 95%
  Identity: ¹H NMR & ¹³C NMR
  Shipping temperature: 20°C
  Storage temperature: -20°C