The synthesis of dihydropyrimidinones is of interest due to their biological activities. A common method for their synthesis is the Biginelli reaction, which is a one-pot multicomponent reaction of an aldehyde, urea and a β -ketoester. The Biginelli reaction is typically catalyzed by a Br?nsted or Lewis acid. However, many of these catalysts, such as BF 3 ?Et 2 O and AlCl 3 are corrosive and/or toxic. Herein, we report the iron(II) triflate-catalyzed (10.0 mol%, 22 - 24 h) synthesis of dihydropyrimidinones via the Biginelli reaction in isopropanol as a solvent. The reaction is also reported in two other solvents, benzotrifluoride (a useful replacement for CH 2 Cl 2 ) and 2-methyltetrahydrofuran, a bio-derived solvent. Iron(II) salts are attractive catalysts because of their low cost, low toxicity, and ease of handling.
KeywordsAldehydesBiginelli Reaction34-Dihydropyrimidin-2(1 H )-onesGreen ChemistryIron(II) TriflateMulticomponent Reactions
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