A process for the preparation of 5 - acetyl (2,3 - dihydroxypropyl) amino - n, n '- to (2,3 - dihydroxypropyl) - 2,4,6 - triiodo - 1,3 - benzene dicarboxylic boxamid

摘要

A process for the preparation of 5-[acetyl(2,3-dihydroxypropyl)amino]-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodo-1,3-benzenedicarboxamide of formula (I), starting from 5-amino-1,3-benzenedicarboxylic acid of formula (II), comprising the following steps: step a) is the reaction in heterogeneous phase between 5-amino-2,4,6-triiodo-1,3-benzenedicarboxylic acid and thionyl chloride in a solvent selected from the group consisting of: straight or branched (C7-C16) hydrocarbons, (C7-C8) aromatic hydrocarbons, 1,1,1-trichloroethane, n-butyl acetate, diglyme (diethylene glycol dimethyl ether), in the presence of catalytic amounts of a tertiary amine, to give compound (III); step b) is the acetylation reaction of compound (III) with glacial acetic acid both as the solvent and the reagent and thionyl chloride; step c) is the formation of compound (V) by reaction of the compound (IV) with 1-amino-2,3-propanediol, by reaction of compound (IV) in a dipolar aprotic solvent, selected from the group of dimethylformamide (DMF), dimethylacetamide (DMA), dimethylsulfoxide (DMSO) or N-methyl-pyrrolidinone; step d) is the alkylation of the compound (V) in aqueous solution at basic pH, by addition of a sodium hydroxide-calcium hydroxide mixture, with 3-chloro-1,2-propanediol or epichlorohydrin, at a temperature of 40-90 DEG C.