Crystal structure of 4-amino-1-benzyl-1,2,4-triazolin-5-one

The title compound, C₉H₁₀N₄O, was obtained unintentionally by hydrolysis of 4-amino-1-benzyl-5-methyl­sulfanyl-1,2,4-triazolium tetra­fluoro­borate in the presence of sodium azide. In the crystal, alternating layers of polar amino­triazolinone and apolar benzene moieties are observed. N—H...O hydrogen bonds between the amino and carbonyl groups form infinite chains along [010]. These infinite chains are linked by additional C—H...O contacts.