Synthesis of Some Hexahydroquinazolinones Using K<sub>3</sub>AlF<sub>6</sub>(Al<sub>2</sub>O<sub>3</sub>/KF) as an Efficient Catalyst in Some Hexahydroquinazolinone Derivatives

Abstract

A protocol for the synthesis of some 4-Aryl-1,3,4,6,7,8-hexahydroquinazolin-2,5(1H,6H)-diones (HHQs) was developed by means of a three-component condensation reaction of an aromatic aldehyde, 1,3-cylohexadione and urea in the presence of K3AlF6 (Al2O3/KF) as catalyst. This reaction is carried out under different conditions including 1) solvent free; 2) reflux in acetonitrile; 3) reflux in ethanol; 4) reflux in chloroform; and 5) reflux in water. In all conditions, the desired products are obtained in high yields after relatively short reaction times. Nevertheless, the reactions proceed faster and in higher yields when they were carried out in acetonitrile. This adopted protocol for some Biginelli-type products has offered the advantages of reusability of the catalyst, high yields and ease of separation of pure products. Furthermore, the catalyst is easily prepared, stabilized and efficiently used under reaction conditions.