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为了深入探索5-烷氧基-3,4-二卤-2(5H)-呋喃酮与胺类试剂发生的反应,进一步在氟化钾作催化剂和四氢呋喃作溶剂的条件下,研究了其与系列不饱和胺的反应,通过旋光度,UV-Vis,IR,1H NMR,13C NMR,MS,元素分析和X射线单晶衍射等表征方法对产物进行结构表征,发现大多数情况下发生预期的串联迈克尔加成-消除反应,得到了16个新的β-胺基-2(5H)-呋喃酮化合物.当不饱和胺为空间位阻较大的2,5-二甲基-3-吡咯啉时,与位阻较大的5-孟氧基-3,4-二卤-2(5H)-呋喃酮反应只是生成异常的2(5H)-呋喃酮开环产物,而与位阻较小的5-甲氧基-3,4-二卤-2(5H)-呋喃酮反应则既有正常的β-胺基-2(5H)-呋喃酮产物,也有经开环重排反应的机理得到的异构体产物.后者表明,底物的位阻大小也是影响反应的因素,甚至导致同时存在竞争反应.
In order to further explore the reaction of 5-alkyloxy-3,4-dihalo-2 (5H) -furanones with amine reagents and further to study the interaction between Series of unsaturated amines, the structures were characterized by optical rotation, UV-Vis, IR, 1H NMR, 13C NMR, MS, elemental analysis and X-ray single crystal diffraction and found that in most cases, A series of Michael addition-elimination reactions gave 16 novel β-amino-2 (5H) -furanones. When the unsaturated amine was sterically hindered 2,5-dimethyl-3-pyrrole The reaction with 5-menthoxy-3,4-dihalo-2 (5H) -furanone with larger steric hindrance only produces an unusual 2 (5H) -furanone ring-opening product, The small 5-methoxy-3,4-dihalo-2 (5H) -furanone reaction is followed by both the normal β-amino-2 (5H) -furanone product and the The result shows that the size of the steric hindrance of the substrate is also a factor that affects the reaction and even leads to the simultaneous presence of competitive reactions.