Ultrasonic assisted synergetic green synthesis of polycyclic imidazo (thiazolo)pyrimidines by using Fe3O4@clay core-shell

A practical and green approach for the ultrasound-enhanced one-pot multicomponent synthesis of tetra heterocyclic imidazo(thiazolo)pyrimidines is described via the condensation of an 2-aminobenzimidazole or 2-aminobenzothiazole, dimedone and various aldehydes in the presence of Fe3O4@clay as an environmentally benign and reusable core/shell nanocomposite catalyst in relatively quantitative yields. This novel eco-friendly protocol includes several advantages such as avoiding hazardous solvents, reusability of the catalyst, easy work-up, short reaction times, room temperature and mild reaction conditions. Furthermore, ultrasonic irradiation and synergistic catalyst showed considerable superiority vs. traditional heating or stirring conditions. (C) 2016 Elsevier B.V. All rights reserved.