Synthesis of 2,3-Dihydroquinazoline-4(1H)-ones

Abstract

An efficient, inexpensive, and heterogeneous catalyst, [Al(H₂PO₄)₃], was applied in a three-component, one-pot cyclocondensation reaction of isatoic anhydride with primary amines (or ammonium salts) and aldehydes to afford the corresponding quinazolinone derivatives in excellent yields. Reactions occurred under thermal solvent-free conditions. It was found that this solid acidic catalyst could be easily recovered and reused for at least three cycles without any loss of activity.

Keywords:

• [Al(H₂PO₄)₃]
• 3-(2′benzothiazolo)-2,3-dihydroqunazoline-4(1H)-ones
• isatoic anhydride
• solvent-free

ACKNOWLEDGMENT

We are thankful to the Sistan and Baluchestan University Research Council for the partial support of this research.

Notes

^a Yield refer to the isolated pure product.

^a The reaction was conducted in an oil bath at 100 °C; the molar ratio of isatoic anhydride, primary amines, benzaldehydes, and Al(H₂PO₄)₃ as catalyst was chosen 1:1.1:1:0.16.

^a The reaction was conducted in an oil bath at 100 °C; the molar ratio of isatoic anhydride, ammonium salts, benzaldehydes, and Al(H₂PO₄)₃ as catalyst was 1:1.2:1:0.16.

^a The molar ratio of isatoic anhydride, benzaldehyde, ammonium acetate, and Al(H₂PO₄)₃ was 1:1:1.2:0.16.

This article is dedicated to Professor Ahmad Akbari, Chancellor of Sistan and Baluchestan University, who dedicates himself to the progress of science.