Preparation method of 6-benzylaminopurine

The invention relates to a preparation method of 6-benzylaminopurine and belongs to the technical field of pesticide synthesis. Aiming at solving the problems that an existing reaction route is long and the quality is poor, the invention provides the preparation method of the 6-benzylaminopurine. The method comprises the following steps: in the presence of a compound catalyst of I2, P2O5 and ZnCl2, enabling hypoxanthine and benzylamine to react in an N,N-dimethylformamide solvent under the condition that the temperature is 50 DEG C to 75 DEG C; regulating the pH (Potential of Hydrogen) value to be neutral to obtain a product, wherein the mass ratio of the hypoxanthine to the compound catalyst is 1 to (0.3 to 0.5); the mass ratio of the P2O5 to the ZnCl2 to the I2 is 1 to (0.2 to 0.3) to (0.01 to 0.02). According to the preparation method provided by the invention, a DMF (Dimethyl Formamide)-P2O5-ZnCl2-I2 compound catalysis system can be formed and has a synergistic effect to finish a one-step method; the preparation method has the advantage that the reaction route is short and can also have the effect of relatively high yield and product purity.