Ecofriendly one-pot synthesis and antiviral evaluation of novel pyrazolylpyrazolines of medicinal interest

Abstract

Ethyl 3-acetyl-1,5-diphenyl-1H-pyrazole-4-carboxylate reacts with a variety of arylaldehydes by grindingmethod in the presence of a catalytic amount of sodium hydroxide at ambient temperature to give the respective chal-cones. The latter compounds react also by grinding method with nitrogen nucleophiles such as hydrazine hydrate, phenyl-hydrazine, and thiosemicarbazide to afford the corresponding pyrazol-3-yl pyrazolines. A series of 6-pyrazolylpyrimidine-2-thione derivatives were prepared by reaction of the above chalcones with thiourea by grinding method in the presenceof a catalytic amount of sodium hydroxide at room temperature. In addition, 7-pyrazolylpyridopyrimidine-3-thione wasprepared by reaction of chalcone with 6-aminothiouracil. All the newly synthesized compounds were characterized onthe basis of elemental analysis and spectral data (IR,1H and13C NMR, mass). Moreover, some of the products wereevaluated for their antiviral activity against the herpes virus at different concentrations. The results obtained indicatedthat compounds4a,4b,4f,5a,5b, and5chave promising activity.