Compounds with bridgehead nitrogen. Part 64—conformational equilibria in the 6-p-nitrophenylperhydrodipyrido[1,2-c: 2′,1′-e]imidazoles
作者:Lee Banting、Trevor A. Crabb
DOI:10.1002/mrc.1260281208
日期:1990.12
The effect of 6-substitution on the conformational equilibria of the perhydrodipyrido[1,2-c:2′,1′-e]imidazoles has been investigated. r-6H,t-11a,t-11b-6-p-Nitrophenylperhydrodipyrido[1,2-c:2′,1′-e]imidazole was found to exist as a pair of enantiomeric non-interconverting N-outside-cis-syn-trans conformers, whereas the r-6H,c-11a,c-11b and r-6H,c-11a,t-11b isomers adopted the trans-syn-trans conformations. Both syn isomers exhibit restricted rotation of the 6-p-nitrophenyl substituent at room temperature and below.
对6-取代对全氢二吡啶并[1,2-c:2′,1′-e]咪唑构象平衡的影响进行了研究。研究发现,r-6H,t-11a,t-11b-6-p-硝基苯基全氢二吡啶并[1,2-c:2′,1′-e]咪唑以一对非互变的N-外侧顺式-顺式-反式构象存在,而r-6H,c-11a,c-11b和r-6H,c-11a,t-11b异构体则采用顺式-顺式-顺式构象。两种顺式异构体在室温及更低温度下均表现出6-p-硝基苯基取代基的受限旋转。