Study On The Ambroxol Addition Reaction Between Electron-deficient Olefins And N-bromosaccharin

In this paper,four different addition reactions of electron deficient olefins reacted with N-bromosaccharins(NBSA)were studied.Firstly,a new addition reaction of chalcone derivatives and N-bromosaccharins(NBSA)was established.Experiments have shown that in the dichloromethane,the chalcone derivatives reacted with N-bromosaccharins(NBSA)could smoothly produce two kinds of addition products under reflux conditions,one was an ether compound and the other was an aminobromination addition product;a new addition reaction of ethyl cinnamate derivatives reacted with N-bromosaccharins(NBSA)was established,too.The ethyl cinnamate derivatives could also react with N-bromosaccharins(NBSA)in a dichloromethane,and two kinds of products could be obtained smoothly at room temperature.One was an ether compound and the other was an aminobromination addition product;the aminobromination reaction of ethyl a-cyanocinnamate derivatives reacted with N-bromosaccharins(NBSA)was established,it had been proved that the a-cyanocinnamate derivatives could be reacted at 50℃ under the catalysis of sodium carbonate in acetonitrile to obtain a single aminobromination product in high yield;a new method for the synthesis of the corresponding dehydroamine from β,β-dicyanostyrene with N-bromosaccharins(NBSA)was established,the experiment proved that in the mixed solvent of dichloromethane and N,N-dimethylformamide(DMF)(V:V=1:1),β,β-dicyanostyrene derivatives could be continuously reacted with NBSA in two steps in one pot under the catalysis of sodium carbonate,the two steps were the addition and elimination reactions to form the corresponding dehydroamine.The remarkable feature of this study is the introduction of benzisothiazole heterocyclic groups on electron-deficient olefins.This core skeleton tends to have strong biological activity and is expected to be used in drug synthesis.The above reaction is simple,mild and has considerable yield up to 95%.