OICC Press Iranian Journal of Catalysis 2345-4865 12 2 2024 01 01 Multicomponent Synthesis of Tetrahydrobenzo[a]xanthene and Tetrahydrobenzo[a]acridine Derivatives using Sulfonated Multi-Walled Carbon Nanotubes as Heterogeneous Nanocatalysts 10.30495/ijc.2022.1955651.1924 EN Shakir Mahmood Saied Department of Medical Laboratory Techniques, Al-Noor University College, Iraq Mohanad Yakdhan Saleh Department of Chemistry, College of Education for pure Science, Mosul University, Ministry of High Education and Scientific Research, Mosul, Iraq 0000-0003-2320-5167 Ahmed M. Hamdoon Branch of Basic Science, College of Agriculture and Forestry, University of Mosul, Iraq Journal Article 2024 01 01 This study is the first report of the application of sulfonated multi-walled carbon nanotubes (MWCNTs-SO3H) in the synthesis of tetrahydrobenzo[a]xanthene and tetrahydrobenzo[a]acridine derivatives. The catalyst was prepared via a chemical approach and the sulfonated groups were attached to the side-wall of MWCNTs with total density of 2.58 mmol.g-1. In order to prove functionalization of the MWCNTs-SO3H, the catalyst was characterized using FE-SEM, TEM, FT-IR, and Raman spectroscopy techniques. A three-component reaction including 2-naphthol, dimedone, and aromatic aldehydes were applied in the synthesis of tetrahydrobenzo[a]xanthene in the presence of 15.5 mol% of MWCNTs-SO3H under solvent-free conditions. Also, a four-component reaction including 2-naphthol, dimedone, aromatic aldehydes, and ammonium chloride was used in the synthesis of tetrahydrobenzo[a]acridine in the presence of 12.9 mol% of MWCNTs-SO3H under solvent-free conditions. All the derivatives of tetrahydrobenzo[a]xanthene and tetrahydrobenzo[a]acridine were obtained in good to excellent yields. The MWCNTs-SO3H was reused in seven consequent catalytic cycles without loss of their catalytic activity. Highlights An efficient and reusable sulfonated multi-walled carbon nanotubes were prepared. MWCNTs-SO3H was used in the synthesis of tetrahydrobenzo[a]xanthene and tetrahydrobenzo[a]acridine. All of the reactions were performed under solvent-free conditions. The MWCNTs-SO3H was characterized using FE-SEM, TEM, FT-IR, and Raman spectroscopy. The catalyst could be reused for seven catalytic cycles.