azide synthons at ambient temperature within 15 min (Fig. 14.7b). In the aspect of
RCY and reaction step, this protocol employing using the
18 F labeled azide synthons is generally known to be more efficient than those using
18 F labeled
cyclooctyne synthons for the
18 F labeling [52].
The bioorthogonal tetrazine-TCO Diels-Alder cycloaddition is also extremely
efficient conjugation reaction for
18 F labeling of peptides. It have been reported that
18 F labeled cRGD [
18 F]x and exendin-4-affine peptide radiotracer could be prepared
in excellent RCYs by this cycloaddition reaction of a
18 F labeled TCO synthon with
the corresponding tetrazine-substituted peptides as shown in Fig. 14.8 [53, 54].
References
1. H.C. Kolb, M.G. Finn, K.B. Sharpless, Click chemistry: diverse chemical function from a few
good reactions. Angew. Chem. Int. Ed. Engl. 40(11), 2004–2021 (2001)
2. C. Mamat, T. Ramenda, F.R. Wuest, Recent applications of click chemistry for the synthesis
of radiotracers for molecular imaging. Mini Rev. Org. Chem. 6(1), 21–34 (2009)
3. T.L. Mindt, H. Struthers, L. Brans, T. Anguelov, C. Schweinsberg, V. Maes et al., “Click to
chelate”: synthesis and installation of metal chelates into biomolecules in a single step. J. Am.
Chem. Soc. 128(47), 15096–15097 (2006)
4. D. Thonon, C. Kech, J. Paris, C. Lemaire, A. Luxen, New strategy for the preparation of
clickable peptides and labeling with 1-(azidomethyl)-4-[
18
F]-fluorobenzene for PET.
Bioconjug. Chem. 20(4), 817–823 (2009)
5. S. Maschauer, J. Einsiedel, R. Haubner, C. Hocke, M. Ocker, H. Hübner et al., Labeling and
glycosylation of peptides using click chemistry: a general approach to
18
F-glycopeptides as
effective imaging probes for positron emission tomography. Angew. Chem. Int. Ed. Engl. 49
(5), 976–979 (2010)
6. J.M. Baskin, J.A. Prescher, S.T. Laughlin, N.J. Agard, P.V. Chang, I.A. Miller et al.,
Copper-free click chemistry for dynamic in vivo imaging. Proc. Natl. Acad. Sci. U.S.A. 104
(43), 16793–16797 (2007)
7. E. Lallana, E. Fernandez-Megia, R. Riguera, Surpassing the use of copper in the click
functionalization of polymeric nanostructures: a strain-promoted approach. J. Am. Chem. Soc.
131(16), 5748–5750 (2009)
Fig. 14.8 Bioorthogonal tetrazine-TCO Diels-Alder cycloaddition for
18
F labeling of peptides
272
D. W. Kim
RCY and reaction step, this protocol employing using the
18 F labeled azide synthons is generally known to be more efficient than those using
18 F labeled
cyclooctyne synthons for the
18 F labeling [52].
The bioorthogonal tetrazine-TCO Diels-Alder cycloaddition is also extremely
efficient conjugation reaction for
18 F labeling of peptides. It have been reported that
18 F labeled cRGD [
18 F]x and exendin-4-affine peptide radiotracer could be prepared
in excellent RCYs by this cycloaddition reaction of a
18 F labeled TCO synthon with
the corresponding tetrazine-substituted peptides as shown in Fig. 14.8 [53, 54].
References
1. H.C. Kolb, M.G. Finn, K.B. Sharpless, Click chemistry: diverse chemical function from a few
good reactions. Angew. Chem. Int. Ed. Engl. 40(11), 2004–2021 (2001)
2. C. Mamat, T. Ramenda, F.R. Wuest, Recent applications of click chemistry for the synthesis
of radiotracers for molecular imaging. Mini Rev. Org. Chem. 6(1), 21–34 (2009)
3. T.L. Mindt, H. Struthers, L. Brans, T. Anguelov, C. Schweinsberg, V. Maes et al., “Click to
chelate”: synthesis and installation of metal chelates into biomolecules in a single step. J. Am.
Chem. Soc. 128(47), 15096–15097 (2006)
4. D. Thonon, C. Kech, J. Paris, C. Lemaire, A. Luxen, New strategy for the preparation of
clickable peptides and labeling with 1-(azidomethyl)-4-[
18
F]-fluorobenzene for PET.
Bioconjug. Chem. 20(4), 817–823 (2009)
5. S. Maschauer, J. Einsiedel, R. Haubner, C. Hocke, M. Ocker, H. Hübner et al., Labeling and
glycosylation of peptides using click chemistry: a general approach to
18
F-glycopeptides as
effective imaging probes for positron emission tomography. Angew. Chem. Int. Ed. Engl. 49
(5), 976–979 (2010)
6. J.M. Baskin, J.A. Prescher, S.T. Laughlin, N.J. Agard, P.V. Chang, I.A. Miller et al.,
Copper-free click chemistry for dynamic in vivo imaging. Proc. Natl. Acad. Sci. U.S.A. 104
(43), 16793–16797 (2007)
7. E. Lallana, E. Fernandez-Megia, R. Riguera, Surpassing the use of copper in the click
functionalization of polymeric nanostructures: a strain-promoted approach. J. Am. Chem. Soc.
131(16), 5748–5750 (2009)
Fig. 14.8 Bioorthogonal tetrazine-TCO Diels-Alder cycloaddition for
18
F labeling of peptides
272
D. W. Kim