2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1<i>H</i>)-ones as substrates for the synthesis of 2,6,8-triarylquinazolin-4-ones
作者:M. J. Mphahlele、M. M. Maluleka、T. A. Khoza
DOI:10.4314/bcse.v28i1.10
日期:——
Direct bromination of 2-aminobenzamide was achieved using N-bromosuccinimide in chloroform-carbon tetrachloride mixture at room temperature for 3 h to afford 2-amino-3,5-dibromobenzamide in high yield and purity. 2-Amino-3,5-dibromobenzamide was, in turn, condensed with benzaldehyde derivatives in the presence of boric acid to afford novel 2-aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1H)-ones. Suzuki-Miyaura cross-coupling of the latter with arylboronic acids yielded the corresponding 2,6,8-triaryl-2,3-dihydroquinazolin-4(1H)-ones. These triarylquinazolin-4(1H)-ones were dehydrogenated using iodine (2 equiv.) in ethanol under reflux to yield the potentially tautomeric 2,6,8-triarylquinazolin-4(3H)-ones.
直接用溴代丁二酸酰亚胺在室温下,于氯仿-四氯化碳混合液中反应3小时,成功实现了对2-氨基苯甲酰胺的溴化反应,生成了高产率和高纯度的2-氨基-3,5-二溴苯甲酰胺。接着,将2-氨基-3,5-二溴苯甲酰胺与醛类衍生物在硼酸存在下进行缩合,得到新型的2-芳基-6,8-二溴-2,3-二氢喹唑啉-4(1H)-酮。随后,使用钯催化的铃木-宫浦交叉偶联反应,将上述产物与芳基硼酸反应,得到了相应的2,6,8-三芳基-2,3-二氢喹唑啉-4(1H)-酮。这些三芳基喹唑啉-4(1H)-酮在乙醇中用碘(2当量)进行脱氢反应,在回流条件下得到潜在的互变异构体2,6,8-三芳基喹唑啉-4(3H)-酮。