OICC Press Iranian Journal of Catalysis 2345-4865 14 3 2024 09 14 One-pot synthesis of pyrimido[4,5-d]pyrimidine derivatives using a new DABCO-based ionic liquid catalyst 10.57647/j.ijc.2024.1403.31 EN Sanaz Sahrapeyma Department of Organic Chemistry, Faculty of Chemistry, University of Guilan, Rasht, Iran Farhad Shirini Department of Organic Chemistry, Faculty of Chemistry, University of Guilan, Rasht, Iran 0000-0002-7204-5000 Manouchehr Mamaghani Department of Organic Chemistry, Faculty of Chemistry, University of Guilan, Rasht, Iran 0000-0002-2054-8685 Journal Article 2024 09 14 In this research, an efficient one-pot synthesis of pyrimido[4,5-d]pyrimidine derivatives has been described using a new DABCO-based ionic liquid catalyst formulated as  [C4(DABCO-SO3H)2].4ClO4. Some of the important features of the reported method are short reaction times, easy work-up and isolation of the products from the reaction media, high yields and reusability of the catalyst. Research Highlights Easy preparation of [C4(DABCO-SO3H)2].4ClO4 as catalyst. Synthesis of pyrimido[4,5-d]pyrimidine derivatives No side reactions and ease of preparation and handling of the catalyst. Reusability of the catalyst.