A practical and tunable transition-metal-free aerobic oxidation of pyrazol-5-ones preparing either 4-hydroxypyrazoles (via C–H hydroxylation) or bispyrazoles (via dehydrogenative homocoupling) is described. The K2CO3/dioxane reagent system predominately promoted hydroxylation to deliver the α-hydroxylated pyrazoles. In contrast, the formation of bispyrazoles was overwhelmingly preferred with CH3CN
介绍了一种实用且可调谐的吡唑-5-酮无过渡金属好氧氧化方法,可制备4-羟基吡唑(通过CH羟基化)或双吡唑(通过脱氢均偶联)。K 2 CO 3 /二恶烷试剂系统主要促进羟基化以递送α-羟基化的吡唑。相反,在没有任何添加剂的情况下,以CH 3 CN作为反应介质,双吡唑的形成是绝对优选的。