Dipropyl 3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine-1,2-dicarboxylate

The title compound, C22H24N4O4, was prepared from propyl chloroformate and 3,6-diphenyl-1,2-dihydro-s-tetrazine. This reaction yields the title compound rather than dipropyl 3,6-diphenyl-1,4-dihydro-s-tetrazine-1,4-dicarboxylate. The 2,3-diazabutadiene group in the central six-membered ring is not planar; the C-N double-bond length is 1.285 (2) Angstrom, and the average N-N single-bond length is 1.401 (3) Angstrom, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie +/-0.3268 (17) Angstrom from the plane of the ring. The molecule has twofold crystallographic symmetry.