Process for the production of praziquantel using phthalimide

摘要

PURPOSE: Provided is a method of preparing Praziquantel which has an excellent effect as a therapeutic agent for distoma hepaticum and pulmonary distomiasis, by using phthalimide instead of aminoacetal used in a conventional method. CONSTITUTION: The preparation method comprises: a) obtaining N-substituted acetylalkyl amine compound like, 2-chloro-N-phenethylacetamide of the formula(3) by reacting arylalkylamine of formula(2) with haloacetyl halide; b) preparing the compound of formula(4), N-phenethylacetamide, by reacting the compound of formula(3) with phthalimide; c) obtaining the compound of formula(5) by reacting the compound represented by formula(4) with hydrazine monohydrate; d) obtaining the compound of formula(6), 2-((2,2-dimethoxyethyl)amino)-N-phenethylacetamide by reacting the compound of formula(5) with bromoacetal and alkylating acetal to amino group; e) preparing the compound of formula(7), 1,2,3,6,7,11b-hexahydro-4N-pyrazino(1,1-a)isoquinoline-4-one by cyclizing the compound of formula(6) with acid; and f) obtaining Praziquantel by alkylating the compound of formula(6).