Magnetic functionalized graphene: An efficient and solid acid catalyst for the synthesis of highly functionalized pyrroles under ultrasound irradiation

A simple and efficient ultrasonic-assisted synthesis of highly functionalized pyrroles by a one-pot multi-component strategy using aromatic amines, phenacyl bromide, and dialkyl acetylenedicarboxylate is reported. The reactions were performed in the presence of magnetic functionalized reduced graphene oxide as the catalyst and under environmentally-friendly solventless conditions. Magnetic functionalized graphene was prepared by a three-step processes, 1) functionalization of graphene oxide with diethyl malonate, 2) simultaneous reduction and further functionalization of graphene oxide with hydroxylamine hydrochloride, and 3) synthesis of functionalized graphene/Fe3O4 catalyst. High yields, mild reaction conditions, easy work‐up, short reaction times, and the reusability of the catalyst are the important features of this protocol.