N -ferrocenylpyridazinones and new organic analogues: Synthesis, cyclic voltammetry, DFT analysis and in vitro antiproliferative activity associated with ROS-generation
Employing an optimized Pd-catalyzed cross-coupling reaction promoted by CuI, novel N-ferrocenylpyridazinones along with N-phenyl- and N-(2-pyridyl) analogues were synthesized from readily available heterocyclic precursors, iodoferrocene, iodobenzene and 2-bromopyridine. With exception of the ferrocenylation of 6-ferrocenylpyridazin-3(2H)-one yielding both N- and O-substituted products, the studied reactions exclusively afforded N-aryl lactams. The novel compounds exhibited cytotoxicity towards HEPG2 and HT-29 human malignant cells under in vitro conditions. The measured IC50 values supplemented with the results of cyclic voltammetry and DFT calculations suggest that the cytotoxic activity of the N- and O-ferrocenyl-substituted derivatives and the decreased effect of the N-phenyl analogues seem to be at least partly associated with the potential to generate reactive oxygen species (ROS). This interpretation, allowing the prediction of characteristic substituent-dependent SAR, was supported by the results of related studies on the practically inactive N-(2-pyridyl)pyridazinones assumed to be present in protonated chelate forms with highly a decreased propensity to undergo ionization. (C) 2017 Elsevier Ltd. All rights reserved.
Nickel chloride catalyzed synthesis of pyrazoles and phthalazin-1(2H)-ones from hydrazines at room temperature
Herein an efficient and simple protocol was developed for the synthesis of pyrazoles and phthalazin-1(2H)-ones from a common precursor hydrazines catalyzed by nickelchloride. The reactions proceeded in water at room temperature. The advantages of the protocol are that both the medicinally important scaffolds could be synthesized with low-cost catalyst, green solvent, relatively lower reaction time