PROCESS FOR IODINATION OF PHENOLIC DERIVATIVES Russian patent published in 2015 - IPC C07C231/10 C07C237/46 

FIELD: chemistry.

SUBSTANCE: invention relates to a process for the preparation of triiodophenol compounds of formula 2, comprising the iodination of a 3,5-disubstituted phenol of formula 1 or a salt thereof, in an aqueous medium, with molecular iodine in the presence of iodic acid, wherein R and R', represent, independently, a group of formula -NHR₁ or -NR₂R₃, wherein each R₁, R₂ and R₃, is, independently, a straight or branched C₁-C₆ alkyl group which is optionally substituted by one or more groups selected from hydroxyl (-OH), C₁-C₅ alkoxy and hydroxyalkoxy groups. Also a process for the preparation of a compounds of formula 5, wherein: R and R' represent, independently, a group of formula 2, and R₄ and R₅, are, independently, hydrogen or a straight or branched C₁-C₆ alkyl group, optionally substituted by one or more hydroxyl or C₁-C₆ alkoxy groups, comprising: (a) preparing a triiodophenol compound of formula 2, said process further comprising: (b) reacting said compound of formula 2, either as such or comprising the phenolic OH-group in the form of a salt with an alkali metal, with a compound of formula R₄HN(C=O)CH(R₅)Z (formula 3), wherein R₄ and R₅ are, independently, as defined above, and Z is a halogen atom selected from chlorine or bromine, or a leaving group selected from methanesulfonyloxy, benzenesulfonyloxy, nitrobenzenesulfonyloxy, and toluensulfonyloxy, to obtain a compound of formula 4; and (c) subjecting said compound of formula 4 to Smiles' rearrangement in the presence of a base to obtain the compound of formula 5.

EFFECT: preparation of triiodinated aromatic compounds of adequate purity for the synthesis of desired iodinated compound (x-ray contrast media).

15 cl, 5 dwg, 8 ex