The invention discloses a improved process for the preparation of 3,5-disubstituted-2,4,6-triiodo aromatic amines of formula (II), wherein R1 and R2 are defined as herein. The compounds of formula (II) are the key intermediates for the synthesis of a series of non-ionic contrast agents such as Iopamidol, Iohexol and Iodixanol. The process comprises reacting chlorine-free iodinating reagents with 3,5-disubstituted-2,4,6-triiodo aromatic amines to obtain 3,5-disubstituted-2,4,6-triiodo aromatic amines of formula (II), wherein the molar yield of the iodination reaction can reach to 89%.
本发明公开了一种改进的方法,用于制备式(II)的3,5-二取代-2,4,6-三
碘芳香胺,其中R1和R2如本文所定义。式(II)化合物是一系列非离子造影剂的合成的关键中间体,例如Iopamidol,Iohexol和Iodixanol。该方法包括将无
氯碘化试剂与3,5-二取代-2,4,6-三
碘芳香胺反应,以获得式(II)的3,5-二取代-2,4,6-三
碘芳香胺,其中
碘化反应的摩尔收率可达89%。