10.3762/bjoc.9.240
The research presents a mild, efficient, and ligand-free method for the direct arylation of 5-pyrazolones using Pd-catalyzed C–H bond activation. The study focuses on the synthesis of 4-aryl-5-pyrazolones, which are significant heterocyclic compounds used in medicinal and biological research. The experiments involved the reaction of 5-pyrazolones with aryl halides using Pd(OAc)2 as a catalyst, with optimization of reaction conditions including the use of different bases, catalysts, solvents, and reaction temperatures. The results were analyzed in terms of product yield, and the optimal conditions were identified as using 0.1 equiv Pd(OAc)2 catalyst, 2.0 equiv Ag2CO3, acetonitrile solvent, 90 °C, air atmosphere, a 1:2 molar ratio of 5-pyrazolone to aryl halide, and a reaction time of 12 hours. The scope of the reaction was also tested with various aryl halides and 5-pyrazolone substrates, showing moderate to excellent yields. The research was supported by several foundations and the characterization data for all compounds is provided in the supporting information.
10.1246/cl.1982.1123
The research focuses on the novel synthesis of 4-azoloyl-2-aminoquinolines, which are heterocyclic compounds with potential biological and medicinal activities. The purpose of the study is to explore the synthetic potential, scope, and limitations of activated nitriles in heterocyclic synthesis. The researchers reported a new method for synthesizing these compounds by reacting 3-cyanomethylene derivatives of isatin (Ia, Ib) with 2-pyrazolin-5-one derivatives (IIa, IIb) and 2-ethoxycarbonylmethyl-2-thiazolin-4-one (X). The process involves equimolar amounts of the reactants being refluxed in ethanol with a catalyst, triethylamine, to yield products with molecular formulas corresponding to the addition of IIa,b to Ia. The study concluded that the synthesized compounds possess latent functional substituents, making them promising for further chemical transformations and of interest for biological studies. The research also noted that this is the first reported conversion of indoles into quinolines via a similar route, expanding the understanding of heterocyclic synthesis.
