Synthesis of Some Biginelli-type Products: Nano Alumina Sulfonic acid (NASA) Catalyzed under Solvent-free Condition

Biginelli-type reaction was developed by means of a three-component condensation of an aldehyde, ethyl acetoacetate, urea or thiourea and nano alumina sulfonic acid (Al2O3-SO3H) (NASA) as catalyzed. It is carried out under different conditions. In all conditions, the desired products are obtained in high yields after relatively short reaction times. Nevertheless, the reactions proceeded faster and in higher yields when they were carried out under solvent-free at 120 °C. Improving product yields and reaction time, NASA was used in a catalytic amount (0.027 mol%). An amount of catalyst used in these reactions is far less than reported (15 mol%). The rate of the reaction was also 24 times faster than the previous rate reported by Shaterian and co-workers by the same yield. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques are used to characterize the microstructural of NASA. Finally, the mechanism of this reaction was studied.