Synthesis, structure, properties of 1,2,4,5-tetrazines

The paper discusses the synthesis of 3,6-diaryl-1,2,4,5-tetrazines by the reaction of aromatic nitriles with hydrazine hydrate in the presence of elemental sulphur. We study the structure of synthesised dihydro-1,2,4,5-tetrazines by 1H NMR spectroscopy, quantum chemical modelling, and the density functional method with a basis set of 6-31G (d,p) basis set. As a result, 1,4-dihydro- are similar to 1,2-dihydrotetrazines in terms of their total energy values. Additionally, the equilibrium in a mixture is in approximately equal amounts for most their substrates. The corresponding 3,6-diaryl-1,2,4,5-tetrazines were synthesised by oxidising the obtained dihydro-1,2,4,5-tetrazines with sodium nitrite in glacial acetic acid. Their structure was confirmed by 1H NMR spectroscopy. The authors forecast effective binding to receptors and enzymes for all synthesised target compounds.