1,2,4,5-Tetrazines, computational studies

Molteni found that nitrilimine 94, generated in situ from hydrazonoyl chloride 93, reacted with electron-poor dipolarophiles (i.e. ethylacrylate in Scheme 5.24) to give pyrazo-lines in water under basic conditions and in the presence of tetrahexylammonium chloride. The presence of surfactant reduced the formation of the by-product 1,2,4,5-tetrazine derivative coming from the dimerization of 94. On the basis of a computational study, the authors conclude that the water has a rather small effect on the cycloaddition with respect to that played by the surfactant. 

LUMO energy levels and atom coefficients in 1,2,4,5-tetrazines 1 (obtained from AMI computational studies). 

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