| 摘要 |
A process for the preparation of 5-amino-2,4,6-triiodoisophthalic acid dichloride by chlorination of 5-amino-2,4,6-triiodoisophthalic acid with thionyl chloride in the presence of a suitable solvent characterized in that the reaction is carried out in the presence of catalytic amounts of a tetraalkylammonium salt of formula R1R2R3R4NX (I) wherein X is halogen, mesylate or tosylate; R1, R2, R3 and R4, the same or different, are C1-C20 alkyl groups so that the total number of carbon atoms of the groups R1, R2, R3 and R4 is higher than 16. The 5-amino-2,4,6-triiodoisophthalic acid dichloride obtained according to the process of the present invention is useful as intermediate in the synthesis of iodinated contrast media. |
