Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones using Boric Acid Aqueous Solution System

Preparation of 3,4-dihydropyrimidin-2(1H)-one (DHPMs) are significant due to their therapeuticand pharmacological properties [1]. The Biginelli reaction was introduced for the firsttime by Pietro Biginelli [2]. In this reaction, 3,4-dihydropyrimidin-2(1H)- ones (DHPMs)were prepared by three-component condensation reaction of aldehyde, urea and ß-ketoester asinteresting compounds with a potential for pharmaceutical applications. Various catalystswere reported for this reaction such as [bmim][MeSO4] [3], FeCl3 [4], RuCl3 [5], and TMSCl[6]. Due to important properties of these compounds, finding the new methods for the synthesisof 3,4-dihydropyrimidin-2(1H)-ones are still needed. Herein, we have reported the preparationof 3,4-dihydropyrimidin-2(1H)-ones in the presence of boric acid, at 90 °C under aqueousconditions (Fig. 1). The prepared compounds were identified by 1HNMR, 13C NMR andIR analysis.