Synthetic Technology Study Of4-(4-methylphenoxy) Benzylamine

4-(4-methylphenoxy)benzylamine is an important intermediate of thetolfenpyrad, the tolfenpyrad is the novel nitrogen-containing heterocyclicparasols insecticides, has unique mechanism, high security and no cross-resistance, and is researched and developed by Mitsubishi Chemical Company ofJapan. According to the synthetic route of the literature, a new synthetic routewith more moderate of the reaction conditions, greener, more convenientoperation and higher yield which is more suitable for the industrial production isdesigned in this paper. Two intermediates and4-(4-methylphenoxy)benzylaminesynthesized in this synthetic route are characterized by HNMR. The synthesisprocesses are further optimized on the basis of the literature and the total yield isincreased to55%, instead of41%from the literature given. The synthesisprocesses optimization mainly includes the following aspects:1. Synthesis of4-(4-methylphenoxy)benzaldehyde. It is more conductive tothe occurrence of a nucleophilic substitution reaction with using the high boilingsolvent N, N-dimethylformamide in place of pyridine, using the phase transfercatalyst tetrabutylammonium bromide in place of the conventional catalystcuprous iodide. It avoids the generation of highly toxic substances hydrogennitride acid, makes the production process more green and is conductive to theprotection of the environment with bromobenzaldenhyde in place ofchlorobenzonitrile in the initial raw material. When the amount of substance ratioof bromobenzaldenhyde to methyl phenol is1:1.3, the amount of substance ratioof potassium hydroxide to methyl phenol is1.2:1, with the phase transfer catalysttetrabutylammonium bromide as a catalyst, the reaction is finished in3hours at135℃, the yield of the product obtained is65%.Compared with the literature, thereaction time is greatly shorted, and the yield have improved to some extent.2. Synthesis of4-(4-methylphenoxy) benzaldehydeoxime.In this paper, It promotes the nucleophilic addition reactions with using the mixture of ethanoland water in place of ethanol. When the amount of substance ratio of4-(4-methylphenoxy)benzaldehyde to hydroxylamine hydrochloride is1:2,the volumeratio of ethanol and water is15:1,with pyridine as a catalyst, the reaction willcome to an end after30minutes under reflux conditions, the yield of the productobtained is95%. Compared with the literature, just the reaction time has beenshortened.3. Synthesis of4-(4-methylphenoxy) benzylamine.For the reduction of4-(4-methylphenoxy)benzaldehydeoxime, using sodium-ethanol or catalytichydrogenation with Raney-Ni reduction, but it requires strict anhydrous orrequires high temperature and pressure, the requirements of the reactionconditions are relatively high. In this paper, using zinc powder-acetic acid system,the reduction reaction can occur under normal temperature and pressureconditions. When the amount of substance ratio of4-(4-methylphenoxy)benzaldehydeoxime to zinc powder is1:5,the reduction reactionis finished in6hours with acetic acid as solvent at30℃~35℃, the yield of theproduct obtained is89%.Compared with other methods, although the yield isalmost all the same, but the operation is more simple and convenient, and its costis reduced.