Synthesis Of β-Amino Ketone Derivatives And Amidoalkyi Naphthols Derivatives By Mannich Reaciton

Mannich reaction is a three-component condensation of amines, aldehydes and acompound containing at least one active hydrogen. The products (Mannich bases) areimportant synthetic intermediates for synthesizing various pharmaceuticals and naturalproducts. In addition, Mannich bases can be used as pesticides, dyes, explosives, paintingsand medicines. β-Amino ketone derivatives and amidoalkyl naphthols derivatives synthesizedin this paper are both important Mannich bases.The three-component one-pot Mannich reaction of aromatic ketones, aromatic aldehydesand aromatic amines catalyzed by aluminium p-toluenesulfonate and aluminium nitrateafforded the corresponding β-amino ketone derivatives efficiently at room temperature. Theeffects of different solvents and reaction conditions on the yields were investigated. In thepresence of aluminium p-toluenesulfonate, the reaction time is3~24h and the yield ofproducts is52%~97%. In the presence of aluminium nitrate, the reaction time is2~24h andthe yield of products is53%~98%. The experimental results indicate the advantages of tworeaction systems are no using poisonous and corrosive organic solvents, mild condition, shortreaction time, high yields and recyclable catalysts. Under the catalysis of aluminiump-toluenesulfonate and aluminium nitrate, the reactions with ortho-substituted aromaticamines have moderate yields too. This results have major improvement compared with thosereported literatures.A protocol for the preparation of amidoalkyl naphthols derivatives fromthree-component one-pot condensation of2-naphthol, aldehydes, amides catalyzed by copperp-toluenesulfonate or silica supported methanesulfonic acid at80oC in water bath undersolvent-free conditions is described. In the presence of copper p-toluenesulfonate, the reactiontime is0.1~12h and the yield of amidoalkyl naphthols is16%~96%; In the presence of silicasupported methanesulfonic acid, the reaction time is0.15~7h and the yield of amidoalkylnaphthols is30%~96%. Compared with conventional methods, two reaction systems havemerits including mild condition, short reaction time, high yield and recyclable catalysts.Under the catalysis of copper p-toluenesulfonate and silica supported methanesulfonic acid,aliphatic aldehydes participate the reaction conveniently. However, little or no products fromaliphatic aldehydes were yielded in the reported methods.