The invention relates to a preparation method of a
ziprasidone intermediate.The preparation method is a method to prepare 6-chloro-2-indolone by one-pot process, an alkali liquid and phase-transfer catalyst low in price are used in the preparation process to substitute the prior art
sodium hydride necessary to use and high in price, recyclable low-grade aliphatic
ketone and low-grade
fatty alcohol are used to substitute DMF (
dimethyl formamide) and DMSO (dimethylsulfoxide) difficult to recycle, the cost is reduced greatly, the materials used herein are cheap and easy to obtain, the process is simple and feasible, posttreatment steps are simplified, particularly the step (1) requires no washing, extracting and purifying operation, one step may be performed directly, the whole operating step needs no use of
column chromatography for purification, the whole preparation process is simplified, and the method is convenient to industrialize; in the synthetic process of formula III compound, a deacidifying process is mild and safe; in the synthesis of formula II compound, low-valence
sulfur-containing compound is used in reduction, generation of
mass waste acid liquid is avoided, production is safe and environment-friendly, and the preparation process is simple and easy.