3,6-Bis(2H-tetrazol-5-yl)-1,2,4,5-tetrazine: A Versatile Bifunctional Building Block for the Synthesis of Linear Oligoheterocycles

3,6-Bis(2H-tetrazol-5-yl)-1,2,4,5-tetrazine (3) (BTT) is an energy-rich compound and a strong dibasic acid. The bifunctional compound 3 is capable of [4+2] cycloadditions through its tetrazine unit as a 4π compound, and of acylating ring-opening reactions through its tetrazole rings, leading to the formation of linear oligoheterocycles 7, 12 with 1,2,4,5-tetrazine, pyridazine, 1,3,4-oxadiazole, thiophene, furan, and pyrrole units in sequences not easily available by other synthetic methods.