摘要
合成了5种不同结构的β-二酮化合物,采用电喷雾质谱、紫外光谱、红外光谱和核磁共振法对其结构进行表征,并讨论了它们的酮式-烯醇式互变异构现象。结果表明,β-二酮分子内酮式-烯醇式的互变异构平衡明显受取代基影响,它们的酮式-烯醇式互变异构体含量完全不同。在固态和CDCl3溶液中,其中2种β-二酮化合物(a1,a2)中主要以烯醇形式存在,仅含有少量的酮式结构;而2种α-取代β-二酮(b1,b2)由于烯醇异构体的空间位阻效应,不能以分子内氢键形成烯醇六元环,全部以酮式结构形式存在;另外,由于强吸电子基团—CF3的作用,使得β-二酮(c)全部以烯醇形式存在。
Five β-diketones compounds with different structures were synthesized. The characteristics of these compounds and their keto -enol tautomeric phenomena were investigated by ESI MS, UV, IR and ^1H NMR spectroscopy. In both solid state and CDCl3 solution, most of the compound al and a2 existed in the enol form, only a small amount existed in the keto form. Two α-substituted β-diketones, including compound b1 and b2 existed wholly in the keto form, since the formation of sixmembered ring compound was hindered by the stereo-hindrance effect of enol isomers. The β-diketones compound c existed wholly in the enol form due to the strong inductive electron-withdrawing effect of --CF3 group. The results indicated that the equilibriums of keto - enol tautomer were strongly influenced by the substitute group in the molecular structure of compound.
出处
《分析测试学报》
CAS
CSCD
北大核心
2009年第4期445-448,共4页
Journal of Instrumental Analysis
基金
湖北省自然科学基金资助项目(J200522002)
湖北省教育厅重大科研资助项目(Z200622001)
