Study of Copper Based Heteropolysalts as Catalysts in the Efficiency of Synthesis of 5-Ethoxycarbonyl-4-Phenyl-6-Methyl-3,4-Dihydropyridin-2(1H)-One

Abstract

The efficiency of various heteropoly compounds as well-known solid acids is investigated for the three-component condensation reaction of an aldehyde, b-ketoester and urea to afford the dihydropyrimidinones (DHPM). Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of excellent yields and short reaction time. The objective of this study is the use of Keggin heteropolyacid (HPAs) noted H3PMo12O40 and its ammonium salts H3-2xCuxPMo12O40 and (NH4)3-2xCuxPMo12O40 in Biginelli cyclocondensation reaction using: benzaldehyde, acetoacetate and urea with ratio (2:2:3) [3]. After synthesis, the prepared catalysts were characterized by: BET surface area, X- ray diffraction, Infra-red spectroscopy and DHPM by FT-IR, 1H and 13C NMR. The reaction results show that H3PMo12O40 is the best catalyst in our reaction conditions with an excellent yield around 94% which can be explained by significantly higher Brønsted acidity compared to that of traditional mineral catalysts. In the other hand, other excellent yields have been obtained in the presence of Cu0.25H2,50PMo12O40 and (NH4)3,00Cu0,00PMo12O40 89% and 59% respectively. Please use 14-point bold for your article title, with an initial capital letter for any proper nouns.