Research On Free Radical-Promoted Synthesis Of Quinolinone Compounds And Dibromination Reaction

Nitrogen heterocyclic compounds are currently the focus of organic synthesis,and are widely used in medical,chemical and another fields.3,4-dihydroquinoline-2(1H)-one derivatives are very common structural skeletons,which exist in many molecules of bioactive substances and natural products.Many synthetic methods have been reported,but they usually require harsh reaction conditions,including strong acids?bases?high pressure?the use of expensive rare metals or complex compounds as substrates.Therefore,it is still a challenging problem to achieve an efficient method for the one-step construction of 3,4-dihydroquinoline-2(1H)-one.Based on the experimental design concept of material economy and environmental friendliness,this paper explored the cascade radical alkylation/cyclization of cinnamamide to synthesize 3,4-dihydroquinoline-2(1H)-one and dibromination reaction of cinnamamide,and realized the construction of carbon-carbon and carbon-bromide,including the following two parts:The first part: N-methyl-N-aryl cinnamon amide and four times the equivalent alkyl aldehyde as raw materials,fluorine benzene as solvents,with 2 mol% acetylacetone iron(III)and 2 times the equivalent two tertiary butyl peroxide as catalyst,this reaction takes 11 hours at 130?.Twenty-nine substituted 3-aryl-4-alkyl-dihydroquinoline-2(1H)-one compounds were prepared via cascade oxidative decarbonylative radical alkylation/cyclization,and the isolated yields is about 78%.The decarbonylation/cyclization reaction has the advantages of low catalyst content,good functional group tolerance and regional selectivity.The second part: N-methyl-N-aryl cinnamon amide and 1.1 times the equivalent four bromide as raw materials,fluorine benzene as solvents,2 times the equivalent benzoyl peroxide as the oxidant,this reaction takes 5 hours at 80? and in oxygen atmosphere.Eight substituted 2,3-dibromo-N-methyl-N,3-diphenylpropanamide compounds were prepared.A nonmetallic catalyzed method for the creation of carbon-bromine bond was developed.The reaction time is short,the temperature is low,and it is easy to operate,and it conforms to the synthetic concept of green economy.Figure [40] table [9] reference [111].