Synthesis of Dihydropyrimidinones Using Large Pore Zeolites

Abstract

A series of dihydropyrimidin-2(1H)-one (DHPM) belongs to one of the important class of therapeutic and pharmacological active compound, were synthesized through the multicomponent reactions (MCRs) of aldehydes, ethyl acetoacetate and urea, followed by the heterogeneous catalyzed Biginelli reaction. In the present endeavour, medium (ZSM-5) and large pore zeolites (Y, BEA and MOR) as well as dealuminated zeolites BEA, were studied as catalysts. An excellent activity for DHPMs synthesis is achieved by optimizing accessibility of the reactants to the active sites and the surface polarity of zeolite catalysts. Moreover, the mechanism of Biginelli reaction was studied by means of GAUSSVIEW energy calculations of adsorbed acylimine intermediate on zeolite by using the density functional method (DFT).

H-ZSM-5 Zeolite Synthesis by Sourcing Silica from the Wheat Husk Ash: Characterization and Application as a Versatile Heterogeneous Catalyst in Organic Transformations including Some Multicomponent Reactions

“…We report the first synthesis of H-ZSM-5 by utilizing wheat husk as a source of silica. As far as highlighting the importance of this original research paper is concerned, it should be stressed that little research was carried out to applications of this catalytic system in the area of multicomponent reactions [32,33]. The novel catalytic applications of H-ZSM-5 are interesting because the organic transformations over this neat zeolite sample are achieved without having to introduce isomorphously substituted or extraframework or impregnated metal ions or clusters.…”

Brønsted Acidic 1-Ethyl-1,2,4-Trizolium Phenylsulfonate as Catalyst for Biginelli Reaction

“…In Biginelli reaction, chemists used number of catalyst like metal salts such as LiBr, FeCl3/Si(OEt)4, Cu(OTf)2, CeCl3 [11][12][13][14][15][16][17][18]. Many types of zeolite catalyzed and inorganic acid catalyzed have been reported for the synthesis of dihydropyrimidinones/ thiones [19][20][21]. However, the above catalyst used in Biginelli reaction protocols are coupled with certain limitations such as less biodegradability of the catalyst, costly reagents for the synthesis of catalyst, drastic reaction conditions and generation of chemical wastages.…”

Synthesis of 1-alkyl triazolium triflate room temperature ionic liquids and their catalytic studies in multi-component Biginelli reaction

“…Those methods involved use of a number of metal salts, such as Li, 6 Fe, [7][8][9][10] Cu, 11,12 Ce, 13 Zr, 14 In, 16 Bi, 17 Yb, 18 La, 19 Al, 20,21 Sn, 22 Mn, 23 Ti 24 and nanomaterials of Fe 3 O 4 . 25 Several zeolite catalyzed [26][27][28] and non-metal acid catalyzed [29][30][31][32] syntheses of dihydropyrimidinone have also been reported. However, some of these * For correspondence procedures are associated with certain limitations such as use of metal catalysts, expensive reagents, and drastic reaction conditions, use of microwave or ultrasonication which often resulted in unsatisfactory yields of product.…”