Synthesis of triphenylpyridines via an oxidative cyclization reaction using Sr-doped LaCoO(3) perovskite as a recyclable heterogeneous catalyst

An La(0.6)Sr(0.4)CoO(3) strontium-doped lanthanum cobaltite perovskite was prepared via a gelation and calcination approach and used as a heterogeneous catalyst for the synthesis of triphenylpyridines via the cyclization reaction between ketoximes and phenylacetic acids. The transformation proceeded via the oxidative functionalization of the sp(3) C–H bond in phenylacetic acid. The La(0.6)Sr(0.4)CoO(3) catalyst demonstrated a superior performance to that of the pristine LaCoCO(3) as well as a series of homogeneous and heterogeneous catalysts. Furthermore, the La(0.6)Sr(0.4)CoO(3) catalyst was facilely recovered and reused without considerable decline in its catalytic efficiency. To the best of our knowledge, the combination of ketoximes with easily available phenylacetic acids is novel.