Reinvestigation of the sulfuric acid-catalysed cyclisation of brominated 2-alkyllevulinic acids to 3-alkyl-5-methylene-2(5H)-furanones
作者:Anthony J. Manny、Staffan Kjelleberg、Naresh Kumar、Rocky de Nys、Roger W. Read、Peter Steinberg
DOI:10.1016/s0040-4020(97)10034-5
日期:1997.11
through bromination and acid promoted lactonisation is described. The underlying reactions have been investigated using levulinic acid as a model, and the effects of varying the bromination conditions and changing acid concentration on product distribution are discussed. Dibromination proceeds best in CHCl3 and proceeds in EtOH-free CHCl3 without the complication of ester formation. Cyclisation occurs
描述了由烷基取代的乙酰丙酸衍生物通过溴化和酸促进的内酯化合成乙基,丁基,己基和十二烷基取代的溴化物。使用乙酰丙酸作为模型,研究了潜在的反应,并讨论了改变溴化条件和改变酸浓度对产物分布的影响。二溴化在CHCl 3中进行得最好,在无EtOH的CHCl 3中进行,而不会形成酯。在98–100%H 2 SO 4中伴随氧化发生环化反应,但在100%H 2 SO 4中产生环戊内酯的产率最高。还描述了相关的贝克雷利物质的形成。