Facile and convenient procedures for the synthesis of dibenzo[a,i]xanthene-diones have been described. The process employs one-pot condensation of aldehydes, 2-hydroxynaphthalene-1,4-dione, and 2-naphthol/2,7-dihydroxynaphthalene/2,6-dihydroxynaphthalene using catalytic sulfuric acid in water under reflux. Task-specific ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim]HSO4), has also been found to be an effective catalyst for this transformation. The protocols defined herein prove to be efficient in terms of high yields, operational simplicity, easy workup, and short reaction time. Also, these compounds were screened for antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay.
已经描述了合成二苯并[a,i]蒽醌二酮的简便和方便的程序。该过程采用在水回流下使用催化硫酸的醛、2-羟基-1,4-萘醌和2-萘酚/2,7-二羟基萘/2,6-二羟基萘的一锅法缩合。特定任务的离子液体,1-丁基-3-甲基咪唑硫酸氢盐([bmim]HSO4),也被发现是这种转化的有效催化剂。此处定义的协议在收率较高、操作简单、易于后处理和反应时间短方面证明是有效的。此外,这些化合物通过2,2-二苯基-1-苦基肼自由基清除剂(2,2-diphenyl-1-picrylhydrazyl, DPPH)进行了抗氧化活性的筛选。