A simple and novel amide ligand based on quinoline derivative used for palladium-catalyzed Suzuki coupling reaction

This paper discusses the synthesis of the amide ligand N,N-diisopropyl quinoline-2-carboxamide from quinoline-2-carboxylic acid and diisopropylamine. The prepared ligand was utilized in the palladium catalyzed Suzuki cross-coupling reaction in ethanol-water 1:1 (v/v). The reaction exhibited high catalytic efficiency with low Pd loading (0.05 mol %) under mild reaction conditions (at 60–90 °C under air atmosphere). In this study, the catalyst was successfully used in coupling reactions between various aryl halides with phenylboronic acid to obtain desired products in excellent yields. Spectrometric methods of 1 H NMR, 13 C NMR, and HR-MS were used to characterize this amide ligand, and its binding properties toward the Pd center were also investigated in detail via HR-MS measurements.