%0 Journal Article
%T Ceric Ion Loaded MCM-41 Catalyzed Synthesis of Substituted Mono- and Bis-dihydropyrimidin-2(1H)-ones
%A Pullar Vadivel
%A Rathinam Ramesh
%A Appaswami Lalitha
%J Journal of Catalysts
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/819184
%X An effective one-pot three-component reaction of aromatic aldehydes with 1,3-diketone and urea or thiourea under solvent-free condition leads to the formation of mono- and bis-dihydropyrimidin-2-(1H)-ones using Ce-MCM-41 as a recyclable solid acid catalyst. This method has several advantages like simple and easy work-up with shorter reaction time, reusability of catalyst, and high yields of Biginelli products. 1. Introduction Multicomponent reactions (MCRs) have been received significantly as a valuable synthetic tool in the field of modern organic synthesis and drug discovery research due to their ability to synthesize target compounds with greater efficiency in single step operations of three or more different monofunctionalized reactants. Moreover, MCRs offer some distinct advantages including atom economy, structural variations, complexity of molecules, and simplicity over conventional step by step synthetic procedures [1¨C8]. Biginelli reaction is a well-known, simple, and straightforward method for the synthesis of 3,4-dihydropyrimidinones (DHPMs) which involves the three-component condensation of an aliphatic or aromatic aldehyde, ¦Â-ketoester, and urea or thiourea. The original reaction was first reported by Biginelli in 1893 catalyzed by mineral acids [9]. Different functionalized 3,4-DHPMs synthesized have exhibited a variety of pharmacological activities such as calcium channel modulation [10], mitotic kinesin Eg5 inhibition (monastrol) [3], antiviral [11], antibacterial, antifungal [12], and anticancer [13]. DHPMs are also used as starting materials for the synthesis of so called ¡°superstatin¡± rosuvastatin, a selective and competitive inhibitor of HMG-CoA reductase [14], the enzyme responsible for the biosynthesis of cholesterol. Moreover, the 3,4-DHPM motif is present in many products isolated from natural material like several species of sponges. Due to the wide range applications, several methods have been reported for the synthesis of dihydropyrimidinones that include the utilization of BF3¡¤OEt2/CuCl [15], lanthanide triflate [16], indium trichloride [17], vanadium (III) chloride [18], cupric chloride [19], LiBr [20], zirconium (IV) chloride [21], lithium perchlorate [22], and polymer-supported ytterbium (II) reagent [23] as well as Bronsted acids, such as p-toluenesulfonic acid [24], silica sulfuric acid [25], KHSO4 [26], and also solid acids like montmorillonite KSF [27], natural HEU-type zeolite [28], and HY-zeolite [29]. However, many of these reported methods suffer from drawbacks such as low yield of products, harsh reaction
%U http://www.hindawi.com/journals/jcat/2013/819184/