Synthesis and Antiviral Investigation of New Polynuclear Heterocyclic Compounds Containing Tetrahydroindazole Derivatives

The antiviral materials or compounds required for the treatment of viruses cause some infectious diseases such as Coxsackievirus B4 (CVB4), rotavirus Wa strain, and adenovirus type 7 are indispensable and of great necessity. The aim of the present study was to synthesize a new series of substituted indazole derivatives obtained from 2-(4-substituted-benzylidene)-4-phenylcyclohexanones and 2,6-bis (4-substituted-benzylidene)-4-phenylcyclohexanone derivatives. The products formed were reacted with 4-hydrazinylbenzoic acid or 2hydrazino- 6-methylbenzothiazole in the presence of cuprous oxide and Cs2CO3 as catalysts to give rise to a variety of indazole derivatives in a simple experimental procedure in good yields and short reaction time. The new compounds were fully characterized by spectroscopic and analytical methods. The synthesized compounds were evaluated for their antiviral activity against Coxsackievirus B4, adenovirus type 7 and rotavirus Wa strain. The bioassay results showed that the synthesized compounds possessed variable antiviral bioactivity. Compound (3-Fluoro-7-(fluoromethylene)-4,5,6,7-tetrahydro-2-(6-methylbenzo[d] thiazol-2-yl)-5phenyl-2H-indazole (24) exhibited moderate activity against both Coxsackievirus B4 and rotavius Wa strain and potentially promising activity against adenovirus type 7. On the other hand, 3-Chloro-7(chloromethylene)-4,5,6,7-tetrahydro-2-(6-methylbenzo[d] thiazol-2-yl)-5-phenyl-2H-indazole (25) and 7-(2,6-Dimethoxybenzylidene)-4,5,6,7-tetrahydro-3-(2,6-dimethoxyphenyl)-2-(6-methylbenzo[d]thiazol-2-yl)-5phenyl-2H-indazole (26) revealed potential promising activity against adenovirus type 7, while compounds 25 and 26 revealed promising activities against rotavirus Wa strain.