Solvent and Copper Ion-Induced Synthesis of Pyridyl-Pyrazole-3-One Derivatives: Crystal Structure, Cytotoxicity.

Five novel compounds, methyl 5-(acetyloxy)-1-(6-bromo-2-pyridinyl)-1H-pyrazole-3-carboxylate (1), methyl 1-(6-bromo-2-pyridinyl)-5-hydroxy-1H-pyrazole-3-carboxylate (2), Trimethyl 1,1',1''-tris(6-bromo-2-pyridinyl)-5,5''-dihydroxy-5'-oxo-1',5'-dihydro-1H,1''H-4,4': 4',4''-terpyrazole-3,3',3''-tricarboxylate (H₂L¹, 3), [Cu₂(L²)₂]·CH₃OH (4), H₂L2A·CH₃CN (5) were synthesized. Compounds 1-5 characterized by elemental analysis, IR, and X-ray single-crystal diffraction. And 1-3 were also characterized by ¹H NMR, 13C NMR and ESI-MS. The H₂L¹, H₂L² were formed by in-situ reaction. H₂L² and H₂L2A are mesomer compounds which have two chiral carbons. The antitumor activity of compounds 1-5 against BEL-7404, HepG2, NCI-H460, T-24, A549 tumor cell lines were screened by methylthiazolyl tetrozolium (MTT) assay. The compounds 1, 2 showed weakly growth inhibition on the HepG2 cell lines. The HepG2 and A549 cell lines showed higher sensitivity to compound 4, while the IC50 values are 10.66, 28.09 μM, respectively. It is worth noting that compounds 1-5 did not show cytotoxicity to human normal liver cell line HL-7702, suggesting its cytotoxic selectivity on these tumor cell lines.