OICC Press Iranian Journal of Catalysis 2345-4865 12 1 2022 03 01 Vitamin B12 used as effective biocatalyst for the synthesis of pyrano[2,3-c]cromenes and pyrano[2,3-d]pyrimidines 10.30495/ijc.2022.689575 EN Ghasem Marandi Organic Chemistry Department, Faculty of Chemistry, Urmia University, Urmia, Iran 0000-0001-8040-0204 Reyhaneh Nadernia Chemistry Department, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran Nourallah Hazeri Chemistry Department, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran Malek Taher Maghsoodlou Chemistry Department, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran Journal Article 2022 03 01 Synthesis of organic compounds using some natural compounds as catalysts has gained more attention in recent decades. With respect to the importance of these procedures, the synthesis of 3,4-dihydropyrano[2,3-c]chromene and pyrano[2,3-d]pyrimidine derivatives using vitamin B12 by a one-pot reaction of malononitrile, benzaldehydes and 4-hydroxycumarine or 1,3-dimethylbarbituric acid is reported.