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(S)-2-(acetyloxy)propanoyl derivative of Compound (II); c) alkaline N 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.

##STR00001##

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(S)-2-(acetyloxy)propanoyl derivative of Compound (II); c) alkaline N 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.

##STR00001##

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(S)-2-(acetyloxy)propanoyl derivative of Compound (II); c) alkaline N 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.

##STR00001##

The invention is related to a process for preparing a iodinating X-rays contrast agent. More specifically, it relates to a process for the preparation of N,N-bis-(2,3-dihydroxypropyl)-5-hydroxy-2,4,6-triiodo-1,3-benzenedicarboxaniide (I) by electrochemical iodination of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide (II) with molecular iodine (I2) which is in situ electrochemically generated from a source of iodide ions (I?). The iodide ions (I?) are obtained by the dissolution of hydrogen iodide (HI) or an alkali metal iodide in the reaction medium or produced during the reaction of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide with I2. The invention also relates to the use of the intermediate compound of formula (I), obtained through the above electrochemical iodination of compound (II), in the preparation of N,N-bis[2,3-dihydroxypropyl]-5(hydroxyacetyl)methylamino]-2,4,6-triiodo-1,3-benzenedicarboxamide (iomeprol).

The invention is related to a process for preparing a iodinating X-rays contrast agent. More specifically, it relates to a process for the preparation of N,N-bis-(2,3-dihydroxypropyl)-5-hydroxy-2,4,6-triiodo-1,3-benzenedicarboxaniide (I) by electrochemical iodination of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide (II) with molecular iodine (I2) which is in situ electrochemically generated from a source of iodide ions (I?). The iodide ions (I?) are obtained by the dissolution of hydrogen iodide (HI) or an alkali metal iodide in the reaction medium or produced during the reaction of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide with I2. The invention also relates to the use of the intermediate compound of formula (I), obtained through the above electrochemical iodination of compound (II), in the preparation of N,N-bis[2,3-dihydroxypropyl]-5(hydroxyacetyl)methylamino]-2,4,6-triiodo-1,3-benzenedicarboxamide (iomeprol).

The invention is related to a process for preparing a iodinating X-rays contrast agent. More specifically, it relates to a process for the preparation of N,N-bis-(2,3-dihydroxypropyl)-5-hydroxy-2,4,6-triiodo-1,3-benzenedicarboxaniide (I) by electrochemical iodination of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide (II) with molecular iodine (I2) which is in situ electrochemically generated from a source of iodide ions (I?). The iodide ions (I?) are obtained by the dissolution of hydrogen iodide (HI) or an alkali metal iodide in the reaction medium or produced during the reaction of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide with I2. The invention also relates to the use of the intermediate compound of formula (I), obtained through the above electrochemical iodination of compound (II), in the preparation of N,N-bis[2,3-dihydroxypropyl]-5(hydroxyacetyl)methylamino]-2,4,6-triiodo-1,3-benzenedicarboxamide (iomeprol).

The invention is related to a process for preparing a iodinating X-rays contrast agent. More specifically, it relates to a process for the preparation of N,N-bis-(2,3-dihydroxypropyl)-5-hydroxy-2,4,6-triiodo-1,3-benzenedicarboxaniide (I) by electrochemical iodination of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide (II) with molecular iodine (I2) which is in situ electrochemically generated from a source of iodide ions (I). The iodide ions (I) are obtained by the dissolution of hydrogen iodide (HI) or an alkali metal iodide in the reaction medium or produced during the reaction of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide with I2. The invention also relates to the use of the intermediate compound of formula (I), obtained through the above electrochemical iodination of compound (II), in the preparation of N,N-bis[2,3-dihydroxypropyl]-5(hydroxyacetyl)methylamino]-2,4,6-triiodo-1,3-benzenedicarboxamide (iomeprol).

The invention is related to a process for preparing a iodinating X-rays contrast agent. More specifically, it relates to a process for the preparation of N,N-bis-(2,3-dihydroxypropyl)-5-hydroxy-2,4,6-triiodo-1,3-benzenedicarboxaniide (I) by electrochemical iodination of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide (II) with molecular iodine (I2) which is in situ electrochemically generated from a source of iodide ions (I). The iodide ions (I) are obtained by the dissolution of hydrogen iodide (HI) or an alkali metal iodide in the reaction medium or produced during the reaction of N,N-(2,3-dihydroxypropyl)-5-hydroxy-1,3-benzenedicarboxamide with I2. The invention also relates to the use of the intermediate compound of formula (I), obtained through the above electrochemical iodination of compound (II), in the preparation of N,N-bis[2,3-dihydroxypropyl]-5(hydroxyacetyl)methylamino]-2,4,6-triiodo-1,3-benzenedicarboxamide (iomeprol).

Alternative continuous downstream processes for the production of 5-acetamido-N,N-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide (Compound A) are described. Compound A is a key intermediate in the production of iodixanol and iohexol, which are two of the biggest commercially available non-ionic x-ray contrast media agents.

Alternative continuous downstream processes for the production of 5-acetamido-N,N-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide (Compound A) are described. Compound A is a key intermediate in the production of iodixanol and iohexol, which are two of the biggest commercially available non-ionic x-ray contrast media agents.