One-Pot Selective Catalytic Synthesis of Pyrrolidone Derivatives from Ethyl Levulinate and Nitro Compounds

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• 作者：Dr. Juan D. Vidal ; Prof. Maria J. Climent ; Prof. Avelino Corma ; Dr Patricia Concepcion and Prof. Sara Iborra
• 刊名：ChemSusChem
• 出版年：2017
• 出版时间：January 10, 2017
• 年：2017
• 卷：10
• 期：1
• 页码：119-128
• 全文大小：1196K
• ISSN：1864-564X

文摘

N-substituted 5-methyl-2-pyrrolidones were prepared in a one-pot process starting from ethyl levulinate and nitro compounds in the presence of a nanosized Pt-based catalyst. Pt supported on TiO₂ nanotubes (Pt/TiO₂-NT) catalyzed the synthesis of N-substituted 5-methyl-2-pyrrolidones through a cascade process involving the reduction of nitro compounds, formation of the intermediary imine, hydrogenation, and subsequent cyclization. A bifunctional metal–acid system was a suitable catalyst for the process. Pt supported on TiO₂ showed lower catalytic activity than Pt/TiO₂-NT owing to the strong adsorption of nitro compounds during the first reaction step that poisoned the acidic sites and strongly decreased the rate of amination and cyclization. However, Pt/TiO₂-NT with milder acid sites was less affected by the adsorption of nitro compounds and the full cascade process could proceed. The results indicate that the prepared Pt/TiO₂-NT is a chemoselective and reusable catalyst that can be applied to the synthesis of a variety of N-substituted 5-methyl-2-pyrrolidones starting from nitro compounds with excellent yields in absence of an additional organic solvent under mild reaction conditions.