Indium(III) Chloride: An Efficient Catalyst for One-pot Multicomponent Synthesis of 2,3-dihydroquinazoline-4(1H)-ones

Background: Multicomponent reactions (MCRs) are one of the most revolutionary concepts in synthetic organic chemistry. By definition, an MCR is a convergent chemical process involving three or more reactants to fabricate products which retain all structural and substructural features of the starting materials. The value of MCRs lies in all areas of synthetic chemistry, as they offer shorter reaction time, uncomplicated process protocol and high yield. We here reported a novel, effortless, ecofriendly multi-component one-pot synthesis of potent 2,3-dihydroquinazoline-4(1H)-ones is disclosed. Methods: The method causes condensation of isatoic anhydride, ammonium salts and aromatic aldehydes in ethanol. The reaction further employs metal chloride catalyst and offers significant advantages including the use of green solvent and unsophisticated work-up methodology. Additionally, the method is of value owing to the excellent yield obtained by the reaction. Results: The multicomponent reaction of isatoic anhydride and ammonium chloride with various aldehydes was investigated in presence of ethanol at reflux for 1.5 h. The catalytic MCR of a substituted aldehyde with ammonium chloride and isatoic anhydride generates 10 products with percentage yield ranging from 84-95%. Conclusion: In a nutshell, it can be stated that indium chloride-catalyzed multi-component reaction is a novel and efficient method for the synthesis of 2,3-dihydroquinazoline-4(1H)-ones. Significant advantages of the method include the use of simple and readily available precursors, high yield and easy workup with short reaction times. Better reactivity of ammonium chloride and high catalytic activity of InCl3 is an added advantage while using ethanol as a green solvent renders the reaction an ecocompatible status.