Carbon Dioxide Mediated Novel Synthesis of Quinazoline-2,4(1<i>H</i>,3<i>H</i>)-dione in Water

Abstract

A novel, efficient, and scalable CO 2 mediated synthesis of quinazoline-2,4(1 H,3 H )-dione was developed by a simple cyclization of 2-aminobenzonitrile with DMF in water as the solvent. This is the first report of its kind. DMF was used as the necessary carbon source in the synthesis of quinazoline-2,4(1 H,3 H )-dione. This synthetic protocol is very efficient; it gives >99% conversion with excellent selectivity. The product was isolated by filtration because of the highly insoluble nature of quinazoline-2,4(1 H,3 H )-dione in water. The co-product, dimethyl amine, also has industrial importance, and the CO 2 that is used can be recycled. This protocol has wide-spread applications in the syntheses of benzimidazole and benzothiazole.