Vol.:(0123456789) Research on Chemical Intermediates https://doi.org/10.1007/s11164-020-04234-4 1 3 Synthesis and characterization of the immobilized polythiophene on magnetic carbon nanotube as a prominent catalyst for the synthesis of dihydropyrimidinone and octahydroquinazolinone derivatives Parisa Akbarzadeh 1  · Nadiya Koukabi 1 Received: 3 May 2020 / Accepted: 5 August 2020 © Springer Nature B.V. 2020 Abstract In this work, the immobilized polythiophene on magnetic carbon nanotube (CNT– Fe 3 O 4 –PTh) was synthesized and introduced as a novel and recoverable catalytic system. The prepared magnetic heterogeneous nanocatalyst was characterized by FT-IR, TGA, EDX, VSM, XRD, TEM, and FE-SEM. Next, the catalytic efciency of CNT–Fe 3 O 4 –PTh was evaluated through the green synthesis of a variety of dihy- dropyrimidinone and octahydroquinazolinone through Biginelli reaction between aromatic aldehydes, urea/thiourea, and β-dicarbonyl compounds under solvent-free conditions. The catalyst was magnetically recovered and recycled for fve cycles without a discernible loss in its catalytic activity. Simple workup, afordability, short reaction times, mild reaction conditions, and the high yield of products are the inter- esting features of this project. Graphic abstract An environmentally benign nanocomposite was prepared using carbon nanotube as an inexpensive, nontoxic, and stable support in the preparation of CNT–Fe 3 O 4 –PTh, which was efciently used as catalyst for the green synthesis of dihydropyrimidinone Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1116 4-020-04234-4) contains supplementary material, which is available to authorized users. * Nadiya Koukabi n.koukabi@semnan.ac.ir 1 Department of Chemistry, Semnan University, Semnan 35131-19111, Iran