Summary: Efficient and fast condensation of anthranilic amide or anthranilic acid with various orthoesters have been carried out using a catalytic amount of Antimony(III) chloride (SbCl3) under microwave irradiation to afford a series of 2-substituted quinazolin-4(3H)-ones in good to excellent yields under solvent free condition.
One of the important features of this methodology is the use of a minimum amount of SbCl3 as an effective Lewis acid catalyst and the avoidance of hazardous organic solvent.
Keywords: Quinazolin-4(3H)-one, Microwave, SbCl3, Solvent-free, Orthoester.
Antimony trichloride (SbCl3) is a useful Lewis acid catalyst with the advantages of inexpensive, easy to treat and good catalytic activity.
Furthermore, to the best of our knowledge, there is no report of the synthesis of quinazolin-4(3H)-ones catalyzed by SbCl3 under microwave irradiation.
2-aminobenzamide (1) (10 mmol), orthoesters (2) (12 mmol) and catalytic amount of SbCl3 were mixed thoroughly in a microwave reactor equipped with a condenser.
Anthranilic acid (4) (10 mmol), orthoester (2) (12 mmol), ammonium acetate (14mmol) and catalytic amounts of SbCl3 were mixed thoroughly in a microwave reactor, equipped with a condenser.