New synthetic approach to substituted isoindolo[2,1-a]quinoline carboxylic acids via intramolecular Diels–Alder reaction of 4-(N-furyl-2)-4-arylaminobutenes-1 with maleic anhydride
作者:Fedor I. Zubkov、Ekaterina V. Boltukhina、Konstantin F. Turchin、Roman S. Borisov、Alexey V. Varlamov
DOI:10.1016/j.tet.2005.02.017
日期:2005.4
Acylation of substituted 4-(furyl-2)-4-arylaminobut-1-enes with maleic anhydride provided 2-allyl-6-carboxy-4-oxo-3-aza-10-oxatricyclo[5.2.1.01,5]dec-8-enes in high yield under mild reaction conditions. The Diels–Alder adducts are formed via an initial amide formation followed by a stereoselective intramolecular [4+2] exo-cycloaddition reaction. Treatment of the tricyclic compounds with phosphoric
用马来酸酐酰化取代的4-(呋喃基-2)-4-芳基氨基丁-1-烯,得到2-烯丙基-6-羧基-4-氧代-3-氧杂-3-氮杂-10-氧杂三环[5.2.1.0 1,5 ] dec在温和的反应条件下,高产率的-8-烯。的狄尔斯-阿德耳加合物通过初始酰胺形成随后是立体选择性的分子内[4 + 2]形成外型-环反应。在高温(70–120°C)下用磷酸处理三环化合物可促进环醚的打开,分子内环化和芳构化,从而得到相应的四环化合物5,6,6a,11-四氢-10-羧基异吲哚[2, 1- a ]喹啉,产量中等。还讨论了酸和反应温度对环化反应的影响。