| 摘要 |
<p>The invention provides an improved process for the preparation of a compound containing a 2,4,6-triiodinated benzene ring, said process comprising reacting a 2,4,6-unsubstituted 5-amino-benzoic acid or derivative thereof with an iodine halide iodinating agent in an aqueous reaction medium, characterised in that the iodinating agent is added to an aqueous medium containing the 5-amino-benzoic acid or derivative at two different temperature ranges: (A) one or more primary portions of the agent are added at a temperature in the range 40 to 70 °C and then one or more secondary portions of the agent are added at a temperature in the range 75 to 95 °C or (B) one or more primary portions of the agent are added at a temperature in the range 75 to 95 °C and then one or more secondary portions of the agent are added at a temperature of 60 to 70 °C.</p> |
