Preparation method of high-purity nitrendipine

A preparation method of high-purity nitrendipine belongs to the field of chemical pharmacy and comprises the following steps: A, adding ethyl acetoacetate, a solvent, a catalyst and m-nitrobenzaldehyde into a reaction container a, uniformly stirring for reaction, and filtering after the reaction is finished to obtain 2-(3-nitrobenzylidene)-ethyl acetoacetate; b, adding methyl acetoacetate into the reaction container b, controlling the temperature to 0-10 DEG C, introducing ammonia gas, preserving heat and reacting, and filtering and drying after the reaction is finished to obtain beta-amino methyl crotonate; and C, adding 2-(3-nitrobenzylidene)-ethyl acetoacetate, beta-amino methyl crotonate and absolute ethyl alcohol into the reaction container c, stirring at 35-45 DEG C for 3-5 hours, heating to 75-85 DEG C, refluxing for 18-24 hours, cooling to 0-10 DEG C after the reaction is finished, crystallizing for 1.5-3 hours, filtering and drying to obtain the high-purity nitrendipine. The nitrendipine with relativ