Synthesis and characterization of the immobilized polythiophene on magnetic carbon nanotube as a prominent catalyst for the synthesis of dihydropyrimidinone and octahydroquinazolinone derivatives

Abstract

In this work, the immobilized polythiophene on magnetic carbon nanotube (CNT–Fe3O4–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 efficiency of CNT–Fe3O4–PTh was evaluated through the green synthesis of a variety of dihydropyrimidinone 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 five cycles without a discernible loss in its catalytic activity. Simple workup, affordability, short reaction times, mild reaction conditions, and the high yield of products are the interesting features of this project. An environmentally benign nanocomposite was prepared using carbon nanotube as an inexpensive, nontoxic, and stable support in the preparation of CNT–Fe3O4–PTh, which was efficiently used as catalyst for the green synthesis of dihydropyrimidinone and octahydroquinazolinone derivatives through Biginelli reaction under solvent-free conditions.