An efficient synthesis of 4,4'-(aryl methylene)-bis (1H-pyrazol-5-ol)s over graphene oxide Functionalized pyridine-methanesulfonate as a novel nanocatalyst

In this study, graphene oxide was functionalized with 3-aminopyridine to prepare a novel nanocatalyst known as the graphene oxide functionalized pyridine-methanesulfonate (GO@PyH-CH3SO3). The GO@PyH-CH3SO3 was then employed as an effective nanocatalyst to prepare 4, 4'-(aryl methylene)-bis(1H-pyrazol-5-ols) via one-pot multicomponent condensation reaction of aldehydes with 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one. The best reaction condition involved the use of 0.02 g of the catalyst for 20 min and at 70 °C without using any solvent. Also, the reusability of catalyst and product yield in five runs was examined and no significant change was observed. The leaching test was utilized to assess the nature of the catalytic activity, and the results showed the heterogeneous condition for the catalytic activity. Efficiently and capability of the GO@PyH-CH3SO3 catalyst and other catalysts were compared and showed the superior properties of this catalyst.