This study describes a new route to the synthesis of novel benzamide-based 5-aminopyrazoles and their corresponding pyrazolo[1,5- a ]pyrimidine and pyrazolo[5,1- c ][1,2,4]triazine derivatives. Benzamide-based 5-aminopyrazoles were prepared through a reaction of benzoyl isothiocyanate with malononitrile in KOH–EtOH followed by alkylation with alkyl halides and then a reaction with hydrazine. In an attempt to react benzoyl isothiocyanate with ethyl cyanoacetate in KOH–EtOH followed by alkylation with methyl iodide at room temperature and then a reaction with hydrazine has resulted in the formation of 3-ethoxy-5-phenyl-1 H -1,2,4-triazole. The structures of the new compounds were characterized by mass spectroscopy, 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy, infrared spectroscopy (IR), and X-ray analysis. The new compounds were tested in vitro for their anti-influenza A virus (subtype H5N1) activity. Among the synthesized compounds, eight compounds 3b , 4 , 10b , 10c , 12a , 19 , 21a , and 21b were found to possess significant antiviral activities against bird flu influenza (H5N1) with viral reduction in the range of 85–65%.

The title compound, C10H11N3O, crystallizes in the triclinic space group P\overline{1} with Z′ = 2. The two independent molecules (A and B) differ in the orientation of the phenyl rings with respect to the plane of the triazine ring, with an interplanar angle of 11.45 (6)° in molecule A and 19.71 (5)° in molecule B, in the opposite sense. In the crystal, classical N—H...N hydrogen bonds cross-link the molecules to form chains parallel to the b axis. Two additional `weak' C—H...O hydrogen bonds link the chains to form layers parallel to (101).

In the structure of the title compound, C15H19N3O5S2, the bond lengths at the linking sulfur atom are significantly different [1.7473 (17) and 1.811 (2) Å], and the angle at the exocyclic nitrogen atom is wide at 128.45 (18)°. The interplanar angle between the tolyl and thiadiazole rings is 9.2 (1)°. The complex hydrogen-bonding pattern, involving five donors and five acceptors, can be broken down into a one-dimensional ribbon parallel to the b axis, involving hydrogen bonds of the sugar residues only, and a two-dimensional layer structure parallel to the ab plane, based on the N—H...O and O—H...N hydrogen bonds.