Study On The Copper-catalyzed Cascade Reaction Of Diels-Alder Reaction And Halogenation

Halogenated heterocyclic compounds are important synthetic intermediates for pesticide, medicine, natural product and functional dye synthesis. In addition, some halogenated heterocyclics have good biological activity. For example 7-halogen-6H-chromeno [4,3-b] quinoline have produced remarkable effects as anti-HBV and anti-cancer. Thus, the development of efficient method for the synthesis of halogenated heterocyclic compounds has attacted considerable attention. While the traditional methods for synthesis of 7-halogen-6H-chromeno [4,3-b] quinoline suffer from certain disadvantages such as poor regioselectivity, multiple steps, harsh reaction condition and so on. Therefore developing simple and economy methods for synthesis 7-halogen-6H-chromeno [4,3-b] quinoline is meaningful.An efficient method for the synthesis of 7-halogen-6H-thiochromeno (chromeno) [4,3-b] quinolines is described in this paper. The optimum reaction condition was obtained when the reaction was treated with Cu2O as catalyst, chloranil as a chlorine source and oxidant, NaCl as an additive, in DME at 80 ℃ for 8 h. The yield of 7-chlorinated-6H-thiochromeno [4,3-b] quinoline and 7-chlorinated-6H-chromeno [4,3-b] quinolone is 57% and 65% respectively.This method has the advance of mild condition, simple operation and cheap catalyst which provide a convenient pathway for synthesis of chlorinated quinoline compounds.