9-Ethyl-6-methyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazepin-8(9H)-one

Abstract

In the title compound, C8H11N5O, the triazepine ring displays a boat conformation. Its mean plane is inclined to the triazole ring by 22.10 (9)°. In the crystal, molecules are linked by C—H...O hydrogen bonds to form chains parallel to theb-axis direction. Inversion-related chains are linkedviaoffset π–π interactions between the triazole rings, forming ribbons propagating in theb-axis direction. The terminal CH3group is disordered over two sets of sites, with a refined occupancy ratio of 0.48 (6):0.52 (6).