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

Ethyl 3-acetyl-1,5-diphenyl-1 H-pyrazole-4-carboxylate reacts with a variety of arylaldehydes by grinding method in the presence of a catalytic amount of sodium hydroxide at ambient temperature to give the respective chalcones. 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 presence of a catalytic amount of sodium hydroxide at room temperature. In addition, 7-pyrazolylpyridopyrimidine-3-thione was prepared by reaction of chalcone with 6-aminothiouracil. All the newly synthesized compounds were characterized on the basis of elemental analysis and spectral data (IR, H-1 and C-13 NMR, mass). Moreover, some of the products were evaluated for their antiviral activity against the herpes virus at different concentrations. The results obtained indicated that compounds 4a, 4b, 4f, 5a, 5b, and 5c have promising activity.