Ugi/Robinson–Gabriel reactions directed toward the synthesis of 2,4,5-trisubstituted oxazoles
作者:Arthur Y. Shaw、Zhigang Xu、Christopher Hulme
DOI:10.1016/j.tetlet.2012.02.030
日期:2012.4
novel concise synthesis of a series of 2,4,5-trisubstituted oxazoles via a tandem Ugi/Robinson–Gabriel sequence. Herein, 2,4-dimethoxybenzylamine 1 was used as an ammonia equivalent in combination with arylglyoxal 3 and supporting Ugi reagents, an isonitrile and carboxylic acid. As such the product of the acid treated Ugi intermediate is ideally configured to undergo a Robinson–Gabriel cyclodehydration
这封信公开了通过串联 Ugi/Robinson-Gabriel 序列一系列 2,4,5-三取代恶唑的新颖简明合成。在此,2,4-二甲氧基苄胺1用作氨当量,与芳基乙二醛3和支持Ugi试剂、异腈和羧酸组合。因此,酸处理的 Ugi 中间体的产物理想地配置为进行 Robinson-Gabriel 环脱水反应,以产生所需的恶唑支架5。