Silica polymer nanocomposites functionalized with polyphosphoric acid: A mild catalyst for efficient one-pot synthesis of dihydropyrimidinones under environmentally benign conditions

ABSTRACT

An efficient, mild catalyst was employed for the synthesis of dihydropyrimidinones via condensation of aldehyde, ethyl acetoacetate, and urea/thiourea in the presence of silica polymer nanocomposite functionalized with polyphosphoric acid. The present methodology offers an advantage of being mild and highly selective wherein a three-component reaction proceeds proficiently because of the synergistic role of the hydrophobic polymer and the acidic sites functionalized on silica, which allows easy removal of water molecule formed during the reaction.

KEYWORDS:

• Mesoporous silica
• polyphosphoric acid
• polymerization
• wet impregnation method
• heterogeneous catalyst
• dihydropyrimidinones

Acknowledgments

The author would like to thank Delhi University for conducting SEM and adsorption isotherm, Indian Institute of Science-Bangalore for Solid State Nuclear Magnetic Resonance (SSNMR), of the samples. The author would like to acknowledge the support of Dr. Ajit Kumar, vice chancellor, NIFTEM.

Funding

The author thanks Department of Science and Technology for financial support via DST-Fast track project SB/FT/CS-011/2013.