Preparation method of azelnidipine intermediate amidine acetate

The invention relates to a preparation method of azelnidipine intermediate amidine acetate, in particular to a modified preparation method of azelnidipine intermediate amidine acetate; the method replaces traditional introduced HCl gas with HCl gas prepared in situ, so that the feeding ratio of starting materials is fully controllable, hydrogen chloride in each batch of reaction liquid is accurately quantitated, and mass reproducibility is good; in addition, only industrial standard materials are used, and advanced water-free treatment is not required; the modified process has greatly lessened operation steps, such as solvent pre-drying, vent pipeline and ventilation regulation and monitoring, ventilation moisture regular monitoring, long ventilation time and the like, and production efficiency is improved; furthermore, the yield and quality of amidine acetate acquired by modification are greatly increased, the yield is up to 75% and above, and the purity of HPLC (high performance liquid chromatography) is up