研究了1-芳基-1,4-二氢吡嗪的光化学性质,包括其紫外可见吸收,光稳定性和光反应性。在常规溶剂中研究了1-芳基-1,4-二氢吡嗪的光稳定性,结果表明1-芳基-1,4-二氢吡嗪在紫外线照射下不稳定。通过1 H NMR,13 C NMR,HRMS和单晶X射线衍射分析确定,1-芳基-1,4-二氢吡嗪经历光化学成环收缩成1-芳基-1 H-咪唑。提出光化学环收缩是通过6π电子环化和[1 + 2]环还原而发生的。
通过将N,N-双烷基化苯胺与乙酸铵环化来制备4-芳基-1,4-二氢吡嗪。这些反应得益于N,N-双烷基化苯胺的合成的改进,N2-N-双烷基化苯胺在无氧乙酸铑的催化下,使用乙酰丙酮-2-重氮乙酯与苯胺烷基化。推测可能的机理路线是基于N烷基化中间体的分离,该中间体经1 H NMR数据和X射线衍射确定为N芳基草酸酯。
The 4‐aryl‐1,4‐dihydropyrazines were prepared via the cyclization of N,N‐bisalkylated anilines with ammonium acetate. These reactions were aided by improvements in the synthesis of N,N‐bisalkylated anilines which were alkylated with anilines using ethyl 2‐diazo acetoacetate in a reaction catalyzed by rhodium acetate in the absence of oxygen. A possible mechanistic route is postulated on the basis of
通过将N,N-双烷基化苯胺与乙酸铵环化来制备4-芳基-1,4-二氢吡嗪。这些反应得益于N,N-双烷基化苯胺的合成的改进,N2-N-双烷基化苯胺在无氧乙酸铑的催化下,使用乙酰丙酮-2-重氮乙酯与苯胺烷基化。推测可能的机理路线是基于N烷基化中间体的分离,该中间体经1 H NMR数据和X射线衍射确定为N芳基草酸酯。
Photochemical ring contraction of 1-aryl-1,4-dihydropyrazine to 1-aryl-1H-imidazole
作者:Hongxing Xin、Wuji Sun、Hong Yan、Xiuqing Song
DOI:10.1016/j.jphotochem.2013.06.010
日期:2013.9
The photochemical properties of 1-aryl-1,4-dihydropyrazines, including their UV–vis absorption, photostability and photoreaction, are investigated. The photostability of the 1-aryl-1,4-dihydropyrazines is studied in conventional solvents, and the results demonstrated that the 1-aryl-1,4-dihydropyrazines are unstable under irradiation with UV light. The 1-aryl-1,4-dihydropyrazines undergo photochemical
研究了1-芳基-1,4-二氢吡嗪的光化学性质,包括其紫外可见吸收,光稳定性和光反应性。在常规溶剂中研究了1-芳基-1,4-二氢吡嗪的光稳定性,结果表明1-芳基-1,4-二氢吡嗪在紫外线照射下不稳定。通过1 H NMR,13 C NMR,HRMS和单晶X射线衍射分析确定,1-芳基-1,4-二氢吡嗪经历光化学成环收缩成1-芳基-1 H-咪唑。提出光化学环收缩是通过6π电子环化和[1 + 2]环还原而发生的。