The reaction can be visualized as proceeding through the formation of the amidine from addition-elimination of anthranilic acid; cyclization then affords the observed product (4). The amide function is then converted to the iminochloride with phosphorus oxychloride. Displacement of the newly introduced halogen by means of diethanolamine affords nifurquinazol chlorine with diethanolamine leads to the formation of nifurquinazol (5), one of the antibacterial nitrofurans.