.4 - (n-phenyl Methyl-n-methyl-amino) Pyridine Resin Catalyst, Preparation And Catalytic Acylation

Based upon extensive investigation on relevant literature and material conditions in our country, immobilized 4-(N-ben.zyl-N- methylamino)pyridine (BMAPR) catalyst was prepared from crosslinked polystyrene and 4-aminopyridine. In the presence of anhydrous ZnCI2, chloromethyl methyl ether and crosslinked polystyrene reacted, forming chloromethylated crosslinked polystyrene (CMCPS). Treated by NaH, the nucleophilicity of amino group of 4-aminopyridine was obviously enhanced, resulted in the nucleophilic replacement reaction occurring on the exocyclic nitrogen atom first. Therefore, under this condition, 4-aniinopyridine reacted with methylation reagent, and then with chloromethyl group of CMCPS, forming the BMAPR catalyst. Being preliminarily used in some acetylation reactions, the catalyst was found that its catalytic ability to alcohol and amine was obvious (except for bulky substrate), to some reaction, even higher than that of 4-dimethylaminopyridine(DMAP) -a 憇upper catalyst? in organic synthesis. At the same time, in order to clarify the mechanism of nucleophilic reaction of 4-aminopyridine, low molar mass model compound was prepared and identified in structure. It was found that under general reaction conditions, nucleophilic replacement reaction of 4-aminopyridine takes place mainly on the heterocyclic nitrogen atom; only in the presence of a super-strong base (NaH), the reaction occurs on the exocyclic nitrogen atom.