ISSN 1070-3632, Russian Journal of General Chemistry, 2017, Vol. 87, No. 4, pp. 842–845. © Pleiades Publishing, Ltd., 2017. 842 1,4-Bis(triphenylphosphonium)-2-butene Peroxodisulfate as an Efficient Oxidizing Agent for One-Pot Synthesis of Ethyl Pyrimidin-2(1H)-one-5-carboxylates 1 M. Gorjizadeh* and M. Afshari Department of Chemistry, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran *e-mail: m.gorjizadeh@iau-shoushtar.ac.ir Received January 11, 2017 Abstract—An efficient one-pot synthesis of pyrimidin-2(1H)-ones via three-component condensation of aldehyde, ethyl acetoacetate and urea using 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate [BTPBPDS] as an oxidant is described. Keywords: pyrimidin-2(1H)-ones, 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate, oxidation, one-pot 1 The text was submitted by the authors in English. INTRODUCTION Multi-component reactions (MCRs), leading to interesting heterocyclic scaffolds, are particularly useful for construction of diverse chemical libraries of “drug-like” molecules. Typically, purification of products accumulated in MCRs is simple because all organic reagents involved are consumed and incorporated into the structure of a target compound [1]. Pyrimidines revealed a wide range of pharma- ceutical activities including antiviral, antimicrobial, gastric antisecretory, diuretic, antimalarial, and anti- HIV [2–7]. Itami and co-workers [8] have reported that pyrimidine cores with extended π-systems exhibited unusual fluorescent properties. Despite of high bio- logical activity of pyrimidines and particularly pyrimidin-2(1H)-ones, only a limited number of syn- thetic approaches to those are available [9]. One of the common methods involves oxidation of 3,4-dihydro- pyrimidin-2(1H)-ones (DHPMs) to pyrimidin-2(1H)- ones. 3,4-Dihydropyrimidin-2(1H)-ones can be easily synthesized from ethyl acetoacetate, an aromatic aldehyde and urea [10]. Dehydrogenation of DHPMs by an oxidizing agent could provide an efficient ap- proach to pyrimidin derivatives. Phosphonium salts have attracted close attention due to their thermal stability, easy handling, non-toxicity, high reactivity, and recyclability [11–13]. As a part of our ongoing study devoted to develop- ing versatile and efficient methods for the synthesis of important heterocyclic compounds [14, 15], we report herein a new procedure for one-pot synthesis of pyrimidin-2(1H)-ones. RESULTS AND DISCUSSION A two-step synthesis of pyrimidin-2(1H)-ones under study is presented in Scheme 1. Thus, the reac- tion of an aromatic aldehyde with ethyl acetoacetate and urea in the presence of catalytic amount of 1,4-bis- (triphenylphosphonium)-2-butene peroxodisulfate (BTPBPDS) led to formation of the corresponding 3,4- dihydropyrimidin-2(1H)-ones 4. 3,4-Dihydropyrimidin-2(1H)-ones 4 bearing a variety of functional groups were prepared in high yields in a short period of time (Table 1). BTPBPDS could play a crucial role in accelerating the steps of dehydration and enolization of the β-ketoester. Subsequently, compounds 4 underwent oxidation by BTPBPDS (Scheme 1, Table 1). This step proceeded within 55–110 min in CH 3 CN under reflux. Sensitive functional groups such as methoxy, nitro, and furyl remained unaffected in the process. According to the recent study [16] adsorption on solid supports (alumina, silica gel, or montmorillonite K-10 clay) can change the reactivity and selectivity of oxidants. The test oxidation of 4 by peroxodisulfate adsorbed by solid supports in the process of dehydro- DOI: 10.1134/S1070363217040284