Xanthan Sulfuric Acid: A New and Efficient Biosupported Solid Acid Catalyst for the Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones

Abstract

Xanthan sulfuric acid (XSA) is employed as a recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones. These syntheses were performed via a one-pot, three-component condensation of aldehydes, amines, and urea/thiourea under solvent-free conditions.

GRAPHICAL ABSTRACT

Keywords:

• Biginelli reaction
• 3,4-dihydropyrimidin-2(1H)-ones
• one-pot synthesis
• solvent-free conditions

ACKNOWLEDGMENT

One of the authors, B. S. K., is grateful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India, for providing financial support in the form of a CSIR Senior Research Fellowship.

Notes

^a Reaction conditions: benzaldehyde (1 mmol), EAA (1 mmol), urea (1.5 mmol), and xanthan sulfuric acid (0.1 g) stirred at 40 °C under solvent-free conditions.

^b Isolated yields.

^c The same catalyst was used for four runs.

^a Reaction conditions: benzaldehyde (1 mmol), EAA (1 mmol), urea (1.5 mmol), and xanthan sulfuric acid (0.1 g) stirred at 40 °C under solvent-free conditions.

^a All the compounds are known; characterized by IR, ¹H NMR, and mass spectral analysis; and compared with the authentic samples.

^b Isolated yields.

^a Reaction conditions: Mixture of benzaldehyde (1 mmol), EAA (1 mmol), urea (1.5 mmol), and xanthan sulfuric acid (0.1 g) stirred at 40 °C under solvent-free conditions.

^b Isolated yield.