A series of different N-heterocyclic carbenes (NHCs) were reacted with 3,6-bis(3',5'-dimethylpyrazolyl)-tetrazine in the presence of an inorganic carbonate to provide access to a hitherto unprecedented compound class. The formed tetrazine derivatives bearing the NHC in the 3-position and an oxygen in the 6-position show a quinoidal-like structure, according to physical examinations and X-ray crystallography.

Other 6-membered heterocycles Other 6-membered heterocycles R 0670 Selective Nucleophilic Substitutions on Tetrazines. -The reaction of tetrazines such as (I) and (VI) bearing two leaving groups with different nucleophiles is studied. -(NOVAK, Z.; BOSTAI, B.; CSEKEI, M.; LOERINCZ, K.; KOTSCHY*, A.; Heterocycles 60 (2003) 12, 2653-2668; Dep. Gen. Inorg. Chem., Eoetvoes Lorand Univ., H-1518 Budapest, Hung.; Eng.) -Mais 14-180

A series of tetrazine derivatives bearing a leaving group were reacted with different nucleophiles to undergo either the expected substitution reaction or an unexpected exchange of the other substituent of the tetrazine ring selectively.The influence of the choice of nucleophile as well as the substituents on the tetrazine was examined in detail and the interpretation of the results was also supported by quantum chemical calculations.

Combined experimental and theoretical investigations helped to elucidate the mechanisms responsible for the unique structural and electronic properties of NHC-substituted tetrazinone compounds.