US 2024/0190830 A1Published application

Process for the preparation of cyclen

AssigneesBracco Imaging S.P.A., Serichim S.R.L.

InventorsWalter BARATTA, Rosario FIGLIOLIA, Pietro DELOGU, Ilaria ADAMO, Mariangela BOCCALON, Federica BUONSANTI

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Abstract

The present invention relates to a process for the preparation of Cyclen. in its turn widely employed in the manufacturing of a variety of macrocyclic gadolinium complexes for use as MRI contrast agents. The said process comprises an efficient coupling of glyoxal with triethylene tetramine and the subsequent reduction of the obtained intermediate derivative with an aluminium based reducing agent. The process is particularly advantageous for the industrial scale as it avoids the use and/or formation of hazardous compounds and further provides for Cyclen manufacturing in high yields and purity.

Claims14

Dependent claims

A process for the preparation of Cyclen which process comprises:

a) reacting glyoxal with triethylene tetramine so as to obtain decahydrodiimidazo[1,2-a:2′,1′-c]pyrazine;
and
b) reducing the thus obtained decahydrodiimidazo[1,2-a:2′,l′-c]pyrazine with a reducing agent selected from the group consisting of dialkyl aluminium hydride, trialkylamine alane complex, or mixtures thereof;
wherein the above alkyl groups, the same or different in each occurrence, are selected from straight or branched C1-C6 alkyl groups, and
wherein step (a) is carried out by adding an aqueous solution of glyoxal to a solution of the amine in anhydrous ethanol, and by carrying out the reaction in a time period of 1 hour or less.

2 more elements

Dependencies are inferred from the claim text.