A set of nicotinic acid derived tetrazines were synthesized and evaluated for activity
in inverse-electron-demand Diels–Alder (IEDDA) reactions with various dienophiles.
It was found that the performance of these tetrazines is governed by two factors.
Theoretical and experimental investigations showed that steric effects may override
the energetically predicted order of reactivity. Making a compromise between reactivity
and stability, a selected tetrazine was incorporated into a deoxynucleotide to afford
a bioorthogonalized building block enabling IEDDA-based tagging schemes of nucleic
acids.
Key words
tetrazine - inverse-electron-demand Diels–Alder reaction - biorthogonal - nucleic
acid - labeling