Photochromism of tetrahydroindolizines. Part XIV: synthesis of cis-fixed conjugated photochromic pyridazinopyrrolo[1,2-b]isoquinolines incorporating carbon-rich linkers

Synthesis of some novel 2-(3-cyano -6-(thiophen- 2-yl)-4,4'- bipyridin-2- yloxy)acetohydrazide derivatives: assessment of their cytotoxic activity

A new series of pyrazole, bipyridine, N-amide derivatives and Schiff bases was synthesized using compound 2-(3-cyano-6- (thiophen-2-yl)-4,4'- bipyridin-2-yloxy) acetohydrazide (3) as a starting material. The compounds structures were confirmed depending on the spectroscopic methods and elemental analysis. Also, the compounds were evaluated as anticancer agents by the compounds screened towards adenocarcinoma breast cancer cell line (MCF-7). The compounds showed a promising cytotoxic effect against human breast cancer cells. Compound 7c showed the most effective activity compared to other compounds with (IC₅₀ = 0.6 ± 0.01 μg mL^-1) in comparison with the reference drug doxorubicin (IC₅₀ = 1.6 ± 0.02 μg mL^-1). While compound 3 is closely active with doxorubicin. Also compounds 2, 4, 6, 7a, 7b and 7d showed noticeable cytotoxic effect. Early and late apoptotic cells were detected using Acridine orange/Ethidium bromide staining technique. The results of biologically screening of the tested compounds give an idea about the importance in the compounds acting against breast cancer and may lead to the discovery of a potent anticancer agent.

Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium

The oxidation kinetics of fluorenone hydrazone (FH) using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.