Bracco Imaging S.p.a.

Daniela Imperio

Luciano Lattuada

Roberta Napolitano

Federica Buonsanti

Elisa Battistini

Frederica Buonsanti

The present invention discloses a process for recovery of a boronic acid of formula R&#x2014;B(OH), wherein Ris selected from the group consisting of C-Clinear or branched alkyl, C-Ccycloalkyl, and Caryl, optionally substituted with a group selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, and phenyl, comprising admixing the boronic acid with a water-immiscible organic solvent in a weight ratio between the boronic acid and the water-immiscible organic solvent from 1:10 to 1:20, adding an aqueous solution to a final pH of neutral, and partitioning the boronic acid into an organic water-immiscible phase and recovery of the organic water-immiscible phase.

Process for the recovery of a boronic acid

The present invention discloses a process for the preparation of Iopamidol of formula (II) and comprising the following steps: a) reacting the Compound (I) wherein X is OR2 or R3, and wherein R2 and R3 are a Ci-C6 linear or branched alkyl, C3-C6 cycloalkyl, C6 aryl, optionally substituted with a group selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl and phenyl, with the acylating agent (S)-2-(acetyloxy)propanoyl chloride in a reaction medium to provide the acetyloxy derivative of Compound (I); b) hydrolyzing the intermediate from step a) with an aqueous solution at a pH comprised from 0 to 7, by adding water or a diluted alkaline solution such as sodium hydroxide or potassium hydroxide, freeing the hydroxyls from the boron-containing protective groups, obtaining the N&#x2014;(S)-2-(acetyloxy)propanoyl derivative of Compound (II); c) alkaline hydrolysis to restore the (S)-2-(hydroxy)propanoyl group and to obtain Iopamidol (II) and optional recovery of the boron derivative from the solution obtained in step b). The boron-containing protective group is versatile, efficient and recyclable. A one-pot synthesis, without intermediate isolation is provided, leading to a decreasing of recovered and recycled solvents and a significant increasing in the yield, representing a significant advantage in terms of cost-effectiveness of the entire process and environmental awareness. 

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Gattinara, Italy

Daniela Imperio