A green approach for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones (and -thiones) using N,N-diethyl-N-sulfoethanaminium hydrogen sulfate

In this paper, a novel SO3H-containing ionic liquid namely N,N-diethyl-N-sulfoethanaminium hydrogen sulfate ([Et3N-SO3H]HSO4) has been synthesized, and characterized by studying its FT-IR, H-1 NMR, C-13 NMR and mass spectra. Afterward, catalytic activity of the Bronsted acidic ionic liquid has been examined for the preparation of 3,4-dihydropyrimidin-2-(1H)-ones and 3,4-dihydropyrimidin-2-(1H)-thiones via the one-pot multi component reaction between arylaldehydes,beta-ketoesters and urea (or -thiourea) under solvent-free conditions. The results showed that [Et3N-SO3H]HSO4 was highly efficient catalyst for this reaction. (C) 2016 Elsevier B.V. All rights reserved.