Preparation method of promecaine hydrochloride

The invention discloses a preparation method of promecaine hydrochloride, which takes 4-chloro-3-nitrobenzoic acid as an initial raw material, and comprises the steps of alkoxylation reaction, esterification reaction, reduction reaction and acidification salification, and in the alkoxylation reaction, n-propyl alcohol, sodium hydride and IIa are used, and the molar ratio of the n-propyl alcohol to the sodium hydride is 1.0: (2.0-3.0): (1.4-2.2); and carrying out decolorization operation after the reduction reaction. The prepared promecaine hydrochloride does not need to be refined, has few impurities, particularly does not contain impurity F, is simple, good in process reproducibility, mild in reaction condition, does not need to be refined, does not relate to low-temperature and high-pressure reactions, has low requirements on equipment, and is suitable for large-scale industrial production. 本发明公开了一种盐酸丙美卡因的制备方法，以4-氯-3-硝基苯甲酸起始原料，经过烷氧基化反应、酯化反应、还原反应和酸化成盐步骤，其中：在所述烷氧基化反应中使用正丙醇和氢化钠，IIa、正丙醇与氢化钠摩尔比＝1.0：2.0～3.0：1.4～2