Study On Synthesis Process Of ?-Arylpropanal

As an important class of compounds,?-arylpropionaldehyde plays an important role in the synthesis of?-arylpropionic acid compouds which are great important anti-inflammatory drugs.Therefore,the research on the synthesis process of?-arylpropanal was theoretically significant and applied value.Herein,?-arylpropionaldehyde was synthesized by epoxidation and rearrangement reaction using aryl ethanone as raw material.The synthesis process of key intermediates was studied;The epoxidation of aryl ethanone and trimethylsulfonium sulfate occurs under the action of sodium hydroxide,and the crude product of epoxidation was directly used in rearrangement reaction without isolation,which was catalyzed by sulfuric acid or FeCl₃ to prepare?-arylpropionaldehyde.The following results were obtained:2-?6-Methoxy-2-naphthyl?propanal was prepared via the epoxidation and rearrangement reaction from 6-methoxy-2-acetonaphthalene.Epoxidation using hydrogen trisulfide as epoxidation reagent.Examine the effect of solvent,material ratio,temperature and reaction time on the reaction The optimum conditions of epoxidation are as follows:methylene chloride as solvent,material ratio n_NaOH:n_{6-methoxy 2-acetonaphthalene}=12:1,reaction temperature was20³0?,reaction time was 3.0 h;under these conditions,the conversion rate of epoxidation of 6-methoxy-2-acetonaphthyl was 100%.The reaction produced three products,which were confirmed by nuclear magnetic resonance as?6-methoxynaphthyl?-1,2-epoxypropane,2-?6-methoxy-2-naphthyl?propanaland2-?6-methoxynaphthyl?-1,2-propanediol;The epoxidation products were directly used for rearrangement without isolation.?1?Using sulfuric acid as rearrangement reaction catalyst,methanol as solvent,the reaction was carried out at reflux temperature for 5.0 h;the overall yield of 2-?6-methoxy-2-naphthyl?prop-anal was 96.9%?calculated from 6-methoxy-2-acetonaphthalene?.?2?12.6%mole of FeCl₃as rearrangement catalyst,ethyl acetate as solvent,the reaction was carried out at 20?for 10min to give 2-?6-methoxy-2-naphthyl?-propanal with overall yield of 90.5%?calculated from6-methoxy-2-acetonaphthalene?.2-?4-Isobutylphenyl?propanal was prepared via the epoxidation and rearrangement reaction using 4-isobutyl acetophenone as raw material.The optimum conditions of epoxidation are as follows:Trimethylsulfonium sulfate as epoxidation reagent,methylene chloride as solvent,material ratio n_NaOH:n_{4-isobutyl acetophenone}=12:1,the reaction was carried out at20³0?for 3.0 h;The conversion rate of epoxidation of 4-isobutyl acetophenone was 100%,and the products were confirmed by GC-MS as 2-?4-isobutylphenyl?propanal and2-?4-isobutylphenyl?-2-methyloxirane;The crude product of oxidation reaction was rearranged under the catalysis of FeCl₃.Ethyl acetate as solvent,12.6%mole of FeCl₃ as catalyst,the reaction was carried out at 20?for 10 min to produce 2-?4-isobutylphenyl?propanal with overall yield of 83.3%?calculated from 4-isobutyl acetophenone?.