We report a green and convenient protocol to prepare 4,7,12,15-tetrachloro[2.2]paracyclophane, the precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way.
我们报告了一种绿色便捷的方法,用于从2,5-二氯-p-二甲苯制备4,7,12,15-四氯[2.2]对环辛烷,这是帕瑞林D的前体。在第一个溴化步骤中,使用H2O2-HBr作为溴源,这个方法变得无机废物和无机溶剂,可以适当地替代现有的溴化方法。Winberg消除-二聚化步骤中,使用水溶性氢氧化钠溶液代替氧化银进行阴离子交换,显著提高了产物产率。此外,还以这种便捷方式制备了四种取代[2.2]对环辛烷。