A process for the preparation of (S)-N,N′-bis[2-hydroxy-1-(hydroxymethyl)ethyl]-5-[(2-hydroxy-1-oxo-propyl)amino]-2,4,6-triiodo-1,3-benzendicarboxamide (iopamidol) starting from 5-amino-N,N′-bis[2-hydroxy-1-(hydroxymethyl)ethyl]-2,4,6-triiodo-1,3-benzenedicarboxamide (II) which process comprises a) reacting the compound of formula (II) with a suitable protecting agent, to give a compound of formula (III) wherein R is a group of formula A or B wherein R
1
is a hydrogen atom, a C
1
÷C
4
straight or branched alkoxy group, R
2
is hydrogen, a C
1
÷C
4
straight or branched alkoxy group and R
3 ?is a C
1
÷C
4
straight or branched alkyl group, a trifuoromethyl or a trichloromethyl group; b) acylating the amino group in position 5 of the intermediate compound of formula (III), by reaction with a (S)-2-(acetyloxy)propanoyl chloride to give a compound of formula (IV) wherein R is as defined above; and c) removing all the acyl groups present in the compound of formula (IV) under basic conditions, with prior cleavage of the cyclic protections of the hydroxy groups in the carboxamido substituents under acidic conditions, when R is a group of formula A carboxamido hydroxy groups under acidic conditions. The invention also refers to the new intermediates of formula (III) and (IV) wherein —R is a group A.
一种制备(S)-N,N'-双[2-羟基-1-(羟甲基)乙基]-5-[(2-羟基-1-氧代-丙基)
氨基]-2,4,6-三
碘-1,3-苯二甲酰胺(iopamidol)的方法,从5-
氨基-N,N'-双[2-羟基-1-(羟甲基)乙基]-2,4,6-三
碘-1,3-苯二甲酰胺(II)开始,该方法包括:a)将式(II)化合物与适当的保护试剂反应,得到式(III)化合物,其中R是式A或B的基团,其中R1是氢原子,C1÷C4直链或支链烷氧基,R2是氢,C1÷C4直链或支链烷氧基,R3是C1÷C4直链或支链烷基,三
氟甲基或三
氯甲基基团;b)通过与(S)-2-(乙酰氧)
丙酰氯反应,酰化式(III)中5位的
氨基,得到式(IV)化合物,其中R如上所述;c)在碱性条件下去除式(IV)化合物中存在的所有酰基,在酸性条件下先裂解羧酰胺取代基中的羟基环保护,当R是式A羧酰胺羟基在酸性条件下。本发明还涉及式(III)和(IV)的新中间体,其中-R是A基团。