The application discloses a preparation method of cinnamyl 3-amino-2-butenoate, and relates to the technical field of preparation of cinnamyl 3-amino-2-butenoate which is a intermediate of cinaldipine. In the method, cinnamyl acetoacetate is added into a mixed reaction
solvent,
liquid ammonia is continuously introduced for reaction at low temperature, after cinnamyl 3-amino-2-butenoate is generated,
ammonia is removed by reduced pressure, and then the temperature is reduced for
crystallization,
filtration is performed, and the obtained product is washed by a
solvent to obtain white cinnamyl 3-amino-2-butenoate
solid. In the application, mixed solvents are used for reaction, and after the reaction is completed, the solvents are not removed by reduced pressure, the heat generated by
ammonia removal by reduced pressure is used to reduce the temperature of the liquid, and
crystallization is performed, so that
energy consumption is saved, the whole process is performed at low temperature,
decomposition of the product caused by high temperature is avoided, and cinnamyl 3-amino-2-butenoate with high purity can be prepared, and the intermediate with high purity is provided for preparation of cinaldipine.