- PROCESS FOR THE PREPARATION OF IOPAMIDOL
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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 hydrolysis to restore the (S)-2-(hydroxy)propanoyl group and to obtain lopamidol (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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Page/Page column 25-26
(2015/05/26)
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- IODINATION PROCESS FOR THE PREPARATION OF 3,5-DISUBSTITUTED-2,4,6-TRIIODO AROMATIC AMINES COMPOUNDS
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The invention discloses a improved process for the preparation of 3,5-disubstituted- 2,4,6-triiodo aromatic amines of formula (II), wherein R1 and R2 are defined as herein. The compounds of formula (II) are the key intermediates for the synthesis of a series of non-ionic contrast agents such as Iopamidol, Iohexol and Iodixanol. The process comprises reacting chlorine-free iodinating reagents with 3,5-disubstituted-2,4,6-triiodo aromatic amines to obtain 3,5-disubstituted-2,4,6-triiodo aromatic amines of formula (II), wherein the molar yield of the iodination reaction can reach to 89%.
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- Process for the preparation of n,n-substituted 5-amino-1,3-benzenedicarboxamides
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The invention relates to a process for the preparation of a compound of formula (I), wherein R represents a 2,3-dihydroxy-1-propyl or a 1,3-dihydroxy-2-propyl radical, via direct amidation of a dialkyl ester of 5-amino-1,3-benzenedicarboxylic acid of formula (V), wherein R1 represents a straight or branched (C1-C4)-alkyl group, with at least the stoichiometric amount of an amine of formula H2NR.
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