This invention discloses a method for synthesizing a key intermediate compound of rumepiride and its preparation, belonging to the field of pharmaceutical intermediates technology. This invention discloses for the first time a novel rumepiride-specific key intermediate, 1-(4-fluorophenyl)-4-(4-piperidinone-1-yl)but-1-one, whose structure is precisely adapted to the requirements of constructing the tetracyclic core of rumepiride, exhibiting excellent
chemical stability and reactivity. This invention provides two independent preparation processes for γ-
hydroxybutyric acid and γ-
aminobutyric acid, adaptable to different
raw material supply scenarios. The high-purity intermediate is prepared through
halogenation, Friedel-Crafts
acylation, nucleophilic condensation or double addition, Dickmann condensation, and
hydrolysis decarboxylation steps. The process of this invention is simple to operate, has mild conditions, few side reactions, and stable yield. The purity of the prepared intermediate is ≥99.5%, and the
impurity index meets the application standards for high-end active pharmaceutical ingredients. It can directly undergo a cyclization reaction with 2-(methylamino)
phenylhydrazine to construct the rumepiride
nucleus, effectively solving the pain points of existing technologies such as cumbersome processes, low yield, and difficulty in controlling impurities. It fills a technological gap in the industry and has extremely high industrial production value and
patent application prospects.