Studies on the reduction of the nitro group in 3-aryl-2-methylene-4-nitro-alkanoates afforded by the Baylis–Hillman adducts: synthesis of 4-aryl-3-methylene-2-pyrrolidinones and 3-(1-alkoxycarbonyl-vinyl)-1H-indole-2-carboxylates
作者:Vijay Singh、Sanjeev Kanojiya、Sanjay Batra
DOI:10.1016/j.tet.2006.08.045
日期:2006.10
formation of substituted 2-pyrrolidinones and indoles by the reduction of the secondary nitro group in appropriate 3-aryl-2-methylene-4-nitroalkanoates afforded by Baylis–Hillman chemistry via different reducing agents is described. The 3-aryl-2-methylene-4-nitroalkanoate obtained from SN2 nucleophilic reaction between the acetate of Baylis–Hillman adducts and ethyl nitroacetate upon reduction with indium–HCl
描述了在适当的3-芳基-2-亚甲基-4-硝基链烷酸酯中,通过不同的还原剂还原适当的3-芳基-2-亚甲基-4-硝基链烷酸酯中的仲硝基,形成取代的2-吡咯烷酮和吲哚。由Baylis–Hillman加合物的乙酸盐和硝基乙酸乙酯(经铟-HCl还原)之间的S N 2亲核反应获得的3-芳基-2-亚甲基-4-硝基链烷酸酯提供了顺式和反式取代的苯基-3-亚甲基- 2-吡咯烷酮。相反,衍生自硝基乙烷的类似底物的类似还原仅选择性地提供了反式取代的苯基-3-亚甲基-2-吡咯烷酮。另一方面,SnCl 2 ·2H 2O-促进的乙酸硝基硝基酯底物的还原生成肟衍生物,而硝基硝基乙烷得到的衍生物则生成顺式和反式4-芳基-3-亚甲基-2-吡咯烷酮的混合物。或者,由SnCl 2 ·2H 2 O促进的由硝基乙酸乙酯提供的取代的2-硝基苯基-2-亚甲基-链烷酸酯的还原产生3-(1-烷氧基羰基-乙烯基)-1 H-吲哚-2-羧酸酯,