Synthesis, spectroscopic and structural studies of 4-Amino-3-(ethyl)-5-(4-chlorophenyl)-4H-1,2,4-triazole and 4-Amino-3-cyclopropyl-5-oxo-4,5-dihydro-1,2,4-triazole-1-yl-acetic acid ethyl ester

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.