A New Phosphotungstic Acid Salt, [Et₃NH]₃PW₁₂O₄₀: Synthesis, Characterization and Its Application as Catalyst in the Synthesis of 4(3H)-Quinazolinones

Abstract

A new Brønsted acidic ionic salt based on Keggin phosphotungstate anion, [Et₃NH]₃PW₁₂O₄₀, has been synthesized using 12-phosphotungstic acid, H₃PW₁₂O₄₀, and triethylamine. The salt has an ionic liquid-like composition but possesses a high melting point. It was characterized by ¹H NMR,¹³C NMR, FT-IR, and CHN analysis, and catalytically evaluated in the synthesis of 4(3H)-quinazolinones by cyclocondensation of 2-aminobenzamide with aroyl chlorides. It showed high catalytic activity with good to excellent yields of the desired products. Furthermore, the products could be separated simply from the catalyst, and the catalyst could be recycled and reused without substantial reduction in its catalytic activity.

Keywords:

• 4(3H)-quinazolinones
• organic heteropolyacid salt
• solid acid
• triethylamine
• 12-phosphotungstic acid

Acknowledgments

The authors are thankful to Islamic Azad University, Mashhad Branch, for financial support.