Fundamental Studies on the Structures and Spectroscopic Properties of Imidazo[1,2-<i>a</i>]pyrazin-3(7<i>H</i>)-one Derivatives
作者:Shunichiro Nakai、Masanori Yasui、Masaki Nakazato、Fujiko Iwasaki、Shojiro Maki、Haruki Niwa、Mamoru Ohashi、Takashi Hirano
DOI:10.1246/bcsj.76.2361
日期:2003.12
O-alkylated derivatives 3–6 have been investigated by X-ray crystallography, UV/vis absorption spectroscopy, NMR, and AM1-COSMO calculations. The crystal structures of 3 and 4 showed that the imidazo[1,2-a]pyrazin-3(7H)-one (imidazopyrazinone) π-system has a planar ring structure and a weakened carbonyl character of the C3–O10 bond, suggesting that the imidazopyrazinone π-system has the character of a zwitter-ionic
2-甲基和2-苯基咪唑并[1,2-a]吡嗪-3(7H)-one 1和2及其N-和O-烷基化衍生物3-6的基本物理性质已通过X射线研究晶体学、紫外/可见吸收光谱、核磁共振和 AM1-COSMO 计算。3和4的晶体结构表明咪唑并[1,2-a]吡嗪-3(7H)-酮(咪唑并吡嗪酮)π-系统具有平面环结构和C3-O10键的弱羰基特征,表明咪唑并吡嗪酮π-系统具有两性离子共振结构的特性以增加芳香性。有关键长交替和 NMR 化学位移 1-4 的数据也支持它们的咪唑并吡嗪酮环具有小部分芳香特性。此外,咪唑并吡嗪酮衍生物 1-4 显示出由与氢键供体溶剂分子的氢键相互作用引起的溶剂化变色;衍生物 1 和 2 在它们的互变异构平衡中优选为 NH 形式的异构体。这些观察...