A Convenient Synthesis, Reactions and Biological Activity of Some New 6H-Pyrazolo[4′,3′:4,5]thieno[3,2-d][1,2,3]triazine Compounds as Antibacterial, Anti-Fungal and Anti-Inflammatory Agents

We describe here the design and synthesis of novel pyrazolothienotriazine compounds based on diazotization followed by cycloaddition reactions of 4-amino-3-methyl-l-phenyl-1H-thieno[2,3-c]pyrazol-5-carbonitrile with sodium nitrite in the presence of concentrated HCl in acetic acid. The produced chloropyrazolothienotriazine underwent nucleophilic substitution reactions with various primary and secondary amines including sulfa drugs to afford the N-substituted aminopyrazolothienotriazines. Hydrazinolysis of the chlorotriazine with hydrazine hydrate afforded the hydrazinotriazine, which was used as a versatile precursor for synthesis of other compounds. The chemical structures of the newly synthesized compounds were confirmed on the basis of elemental and spectral analyses containing Fourier transform infrared spectroscopy (FTIR), H-1 and C-13 nuclear magnetic resonance (NMR) and mass spectrometry. Some of the synthesized compounds showed high antibacterial and anti-fungal activities. Also, most of the tested compounds exhibited high anti-inflammatory activity compared with indomethacin using carrageenan induced rat paw edema assay.