Studies On The Synthesis Of Chromene And Quinolinone Derivatives

This thesis is mainly about the development of novel synthetic strategies for the preparation of 4H-chromenes and quinolinones by using o-bromobenzyl bromide as a key precursor.It includes the following two parts.In the first part,the reaction of o-bromobenzyl bromide with 1,3-dicarbonyl compound was studied.It was discovered that under the promotion of Cul and K2CO3,o-bromobenzyl bromide and 1,3-dicarbonyl underwent a tandem process to give 4H-chromenes in moderate to high yields under mild reaction conditionsThe second part of this thesis focuses on the reaction of o-bromobenzyl bromide with cyanoacetamide.Firstly,it was found that 3,4-dihydro-3-cyano-3-(2’-bromobenzyl)quinolinone could be efficiently obtained through CuI/K2CO3 promoted tandem reaction of cyanoacetamide with o-bromobenzyl bromide in ethylene glycol.Next,3,4-dihydro-3-cyano-3-(2’-bromobenzyl)quinolinones were transformed into 3-(2’-bromobenzyl)quinolinones through sodium methoxide promoted elimination of hydrogen cyanide.Thirdly,upon treating with CuI/K2C03,3-(2’-bromobenzyl)quinolinones could undergo a cascade process including intramolecular coupling and oxidation to afford chromenono[2,3-b]quinoline in moderate to good yields.In summary,some synthetically and biologically interesting heterocycles such as 4H-chromenes,3,4-dihydro-3-cyano-3-(2’-bromobenzyl)quinolinones and chromenono[2,3-b]quinolines were synthesized by using o-bromobenzyl bromide as a valuable material..Compared with literature methods toward these heterocyclic compounds,the new synthetic methods presented here have advantages such as rapid reaction rate,mild conditions,and high efficiency.