This invention belongs to the field of pharmaceutical
material synthesis technology, specifically relating to a preparation process of
metoclopramide. The invention first hydrolyzes 4-acetamido-5-chloro-2-methoxybenzoate to obtain the
hydrolysate 4-amino-5-chloro-2-methoxybenzoic acid. Then,
dichloromethane, the
hydrolysate, and N,N'-
carbonyldiimidazole are added to a reaction vessel, and the mixture is heated to 40-50°C and maintained at this temperature. After the reaction, N,N-diethylethylenediamine is added dropwise to the reaction solution, controlling the temperature inside the reaction vessel to not exceed 43°C during the addition. After the addition is complete, the mixture is kept under
reflux and the reaction is maintained at this temperature. Crude
metoclopramide is obtained after the reaction, which is then purified to obtain
metoclopramide. This invention achieves a high yield and improved purity of metoclopramide through the optimization of various conditions, such as screening and determining the
raw material ratio and controlling the type and amount of
solvent.