Process for the preparation of 5-amino-2,4,6-Triiodoisophthalic acid dichloride by chlorination with thionyl chloride in the presence of a catalyst
US5663432A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1996 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | May 17, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C227/18
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
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 EQU R.sub.1 R.sub.2 R.sub.3 R.sub.4 NX (I) wherein X is halogen, mesylate or tosylate; R.sub.1, R.sub.2, R.sub.3 and R.sub.4, the same or different, are C.sub.1 -C.sub.20 alkyl groups so that the total number of carbon atoms of the groups R.sub.1, R.sub.2, R.sub.3 and R.sub.4 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.