Sulfonic Acid-Functionalized (Bio)Materials as Catalysts for Efficient Amide Bond Synthesis

Funding Information: The authors thank Fundação para a Ciência e Tecnologia (FC&T) for project PTDC/BII‐BIO/30884/2017 and EXPL/BII‐BIO/0436/2021 and also for the researcher contract 2021.03255.CEECIND (M.C.C) and 2020.01614.CEECIND/CP1596/CT0007 (A.F.P.). Authors also thank the support by the Associate Laboratory for Green Chemistry – LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020) and i3 N (LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 . The National NMR Facility is supported by FC&T (ROTEIRO/0031/2013 – PINFRA/22161/2016, co‐financed by FEDER through COMPETE 2020, POCI, and PORL and FC&T through PIDDAC) and CERMAX through project 022162. We thank Prof. Dr. Carlos A. M. Afonso from the Faculty of Pharmacy, ULisboa for the scientific discussions on the experiments carried out with furfuryl alcohol derivatives. Publisher Copyright: © 2023 The Authors. ChemCatChem published by Wiley-VCH GmbH. Sulfonic acid carbon-(bio)based and natural clays-based catalysts were prepared and investigated for the first time as heterogeneous catalysts for amide bond synthesis by a Ritter reaction. The different SO3H-catalysts were screened using benzyl alcohol and acetonitrile as model substrates, and MWCNT-CSP revealed to be an efficient catalyst, affording the amide in 75 % yield. The practical utility of the catalysts was demonstrated by a diverse range of amides, obtained from alcohols and nitriles, in moderate to good yields. Biomass derived platform alcohols, such as 5-HMF and furfuryl alcohol, were also tested as potential building blocks for the synthesis of biopolymers. The SO3H-catalysts revealed to be a highly efficient and environmentally friendly alternative to the conventional acid catalysts commonly used in the Ritter reaction. publishersversion published