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Kinetic studies of inverse electron demand Diels-Alder reactions (iEDDA) of norbornenes and 3,6-dipyridin-2-yl-1,2,4,5-tetrazine.

Knall AC, Hollauf M, Slugovc C - Tetrahedron Lett. (2014)

Bottom Line: Norbornenes are, due to their straightforward synthetic availability, especially interesting in the latter context.Therefore, the reactivity of different norbornene-based compounds was compared with unsubstituted norbornene and other alkenes using UV-vis measurements for the determination of reaction rates under pseudo first order conditions.Thereby, exo,exo-5-norbornene-2,3-dimethanol was found to be almost as reactive as unsubstituted norbornene whereas (±)-endo,exo-dimethyl-5-norbornene-2,3-dicarboxylate reacted only insignificanty faster than unstrained alkenes.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemistry and Technology of Materials (ICTM), Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria.

ABSTRACT
Inverse electron demand Diels-Alder additions (iEDDA) between 1,2,4,5-tetrazines and olefins have recently found widespread application as a novel 'click chemistry' scheme and as a mild technique for the modification of materials. Norbornenes are, due to their straightforward synthetic availability, especially interesting in the latter context. Therefore, the reactivity of different norbornene-based compounds was compared with unsubstituted norbornene and other alkenes using UV-vis measurements for the determination of reaction rates under pseudo first order conditions. Thereby, exo,exo-5-norbornene-2,3-dimethanol was found to be almost as reactive as unsubstituted norbornene whereas (±)-endo,exo-dimethyl-5-norbornene-2,3-dicarboxylate reacted only insignificanty faster than unstrained alkenes.

No MeSH data available.


Related in: MedlinePlus

Linear dependence of pseudo first order reaction rate constants on the alkene concentration for 1, 3, 9 and 17.
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f0010: Linear dependence of pseudo first order reaction rate constants on the alkene concentration for 1, 3, 9 and 17.

Mentions: For the kinetic experiments, solutions of pyTz and the respective alkene (both in methanol) were mixed in cuvettes in a UV-vis photometer so that a final concentration of 1 mM pyTz and 10, 14, 16 and 20 mM of alkene substrate was achieved and the iEDDA reaction was initiated. Immediately after, the decay of tetrazine concentration was monitored for five minutes (10 s interval) at a wavelength of 545 nm. The pseudo-first order reaction rate constants were then determined by linear fits of ln([pyTz]/[pyTz0]) plotted versus reaction time. This procedure was repeated three times for each concentration. Linear regression with the alkene concentration allowed deriving the second rate order constants for the respective alkene–tetrazine couples (shown in Fig. 2).


Kinetic studies of inverse electron demand Diels-Alder reactions (iEDDA) of norbornenes and 3,6-dipyridin-2-yl-1,2,4,5-tetrazine.

Knall AC, Hollauf M, Slugovc C - Tetrahedron Lett. (2014)

Linear dependence of pseudo first order reaction rate constants on the alkene concentration for 1, 3, 9 and 17.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4125744&req=5

f0010: Linear dependence of pseudo first order reaction rate constants on the alkene concentration for 1, 3, 9 and 17.
Mentions: For the kinetic experiments, solutions of pyTz and the respective alkene (both in methanol) were mixed in cuvettes in a UV-vis photometer so that a final concentration of 1 mM pyTz and 10, 14, 16 and 20 mM of alkene substrate was achieved and the iEDDA reaction was initiated. Immediately after, the decay of tetrazine concentration was monitored for five minutes (10 s interval) at a wavelength of 545 nm. The pseudo-first order reaction rate constants were then determined by linear fits of ln([pyTz]/[pyTz0]) plotted versus reaction time. This procedure was repeated three times for each concentration. Linear regression with the alkene concentration allowed deriving the second rate order constants for the respective alkene–tetrazine couples (shown in Fig. 2).

Bottom Line: Norbornenes are, due to their straightforward synthetic availability, especially interesting in the latter context.Therefore, the reactivity of different norbornene-based compounds was compared with unsubstituted norbornene and other alkenes using UV-vis measurements for the determination of reaction rates under pseudo first order conditions.Thereby, exo,exo-5-norbornene-2,3-dimethanol was found to be almost as reactive as unsubstituted norbornene whereas (±)-endo,exo-dimethyl-5-norbornene-2,3-dicarboxylate reacted only insignificanty faster than unstrained alkenes.

View Article: PubMed Central - PubMed

Affiliation: Institute for Chemistry and Technology of Materials (ICTM), Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria.

ABSTRACT
Inverse electron demand Diels-Alder additions (iEDDA) between 1,2,4,5-tetrazines and olefins have recently found widespread application as a novel 'click chemistry' scheme and as a mild technique for the modification of materials. Norbornenes are, due to their straightforward synthetic availability, especially interesting in the latter context. Therefore, the reactivity of different norbornene-based compounds was compared with unsubstituted norbornene and other alkenes using UV-vis measurements for the determination of reaction rates under pseudo first order conditions. Thereby, exo,exo-5-norbornene-2,3-dimethanol was found to be almost as reactive as unsubstituted norbornene whereas (±)-endo,exo-dimethyl-5-norbornene-2,3-dicarboxylate reacted only insignificanty faster than unstrained alkenes.

No MeSH data available.


Related in: MedlinePlus