1,3-dipolar cycloaddition reactions of 2-substituted azomethine N-oxides with N-benzyl maleimides leading to the synthesis of stereoisomers
作者:Rahul Badru、Sakshi Shah、Baldev Singh
DOI:10.1002/jhet.794
日期:2012.3
The azomethine N‐oxides (1) on reacting with N‐benzylmaleimide (2) provide a mixture of stereoisomers 2,3‐diphenyl‐5‐benzyl‐4H‐2,3,3a,5,6,6a‐hexahydropyrrolo[3,4‐d]isoxazole‐4,6–dione derivatives (3) in good yields. These isomers have been assigned cis and trans configurations (3‐A and 3‐B) with respect to proton C3‐H on the azomethinic carbon on the basis of their PMR and H‐NMR COSY data. The ratio
与N-苄基马来酰亚胺(2)反应时,偶氮甲碱N-氧化物(1)提供了立体异构体2,3-二苯基-5-苄基4 H -2,3,3a,5,6,6a-六氢吡咯[3]的混合物,4 - d ]异恶唑-4,6-二酮衍生物(3),收率高。根据其PMR和H-NMR COZY数据,已将这些异构体相对于偶氮二甲基碳上的质子C 3 -H分配了顺式和反式构型(3-A和3-B)。发现顺式和反式异构体之间的比例取决于存在于C的邻位的取代基-苯基醛基部分。这些1,3-偶极环加成反应的显着特征在于,N-苄基部分上的苄基质子遭受宝石耦合,表明磁性不等价。J.杂环化学。,(2012)。