A Novel Method To Synthetize Aromatic Amides From Aromatic Benzaldehydes And Amines

Amide compounds are of great value in our life and industry production, they werewidely used in producing medicine, pesticide, chemical reagents, dyes, synthetic rubber, finechemical products. We worked out a new method to synthesize amide compounds fromaromatic aldehydes and amines in mild reaction conditions,not using the coupling methods,oxidation methods and Metal-catalyzed methods,but using the bases as catalyst. The maincontents are as follows:1. We found a new way to synthesize amide compounds from aldehydes and aminesunder the bases’catalyzed In the same time, We run the reaction between aliphatic aldehydesand amides, as well as benzaldehydes and amides, aliphatic amines or aromatic aminescatalyzed by t-BuOK, in the result, we found no reaction happened either between aliphaticaldehydes and amides, nor aromatic benzaldehydes and amines, tertiary amines and aromaticamines. We could obtaine the corresponding amides from the reaction between aromaticbenzaldehydes and DMF, N,N-diethylformamide and the secondary amine.2. Screening over many bases, including inorganic base (NaOH, NaH) and organic base(MeONa, EtONa, t-BuOK). When using NaOH and MeONa, we didn’t obtain amides asexpected, the products are the same as Cannizzaro reaction’s. While using NaH, EtONa andt-BuOK,we could get the Corresponding amides, and when the strength of alkalis becomeweaker and weaker, the yield of amides become higher and higher. The yield reached thehighest point when using t-BuOK as the base. We also examined the reaction conditions(temperature, solvent, reaction time, concentration and substrate ratio). The optimal reactionconditions between aromatic benzaldehydes and the amides we have worked out was:aldehyde/amine/t-BuOK=1:1.5:1.5, THF as solvent,50℃,2h;and also the optimal reactioncondition of aromatic benzaldehydes and secondary amines was: aldehyde/amine/t-BuOK=1:1.5:1.5, THF as solvent,50℃,1.5h. Compared to methods reported by other literatures, theconditions used in our method is milder because the temperature and reaction time are only25℃and0.5h instead of above70℃and3-5h respectively. Moreover, no strong oxidants,expensive metals and other additives are needed in our system. Finally, we expanded therange of the substrates,and characterized the products.3. We proposed the possible mechanism of the reaction between aromatic benzaldehydesand DMF, N,N-diethylformamide,as well as the reaction between aromatic benzaldehydesand the secondary amines，found that they were not the same.