Synthesis and new rearrangements of 4-isoxazolin-4,5-dicarboxylic acid derivatives
作者:Necdet Coşkun、Aylin Öztürk
DOI:10.1016/j.tet.2006.09.074
日期:2006.12
Acyclic nitrones react with dimethyl acetylenedicarboxylate (DMAD) to give stable isoxazolines, from which the ones that contain electron-donating aromatic rings at the C3 position (R1) were shown to undergo unprecedented fragmentation at room temperature, giving the R1-aldehyde and inseparable product mixtures, probably due to the formation of highly reactive species such as iminocarbenes. Attempts
无环硝酮与乙炔二甲酸二甲酯(DMAD)反应生成稳定的异恶唑啉,据显示,异恶唑啉在C3位置(R 1)含给电子性芳环的那些在室温下经历了空前的断裂,得到R 1醛和不可分离的产物混合物,可能是由于形成了高反应性的物质,如亚氨基卡宾。试图通过在甲苯中回流将异恶唑啉转化为相应的稳定的甲亚胺基亚胺,再次导致与上述相同的产物混合物(例如,室温分解)。当异恶唑啉在室温下与甲醇反应时,可提供高度官能化的非对映异构体混合物。同样,当异恶唑啉与丙胺反应时,可以区域选择性地产生相应的酰胺,所有这些酰胺都比母体异恶唑啉更稳定。