Dibra S.p.a.

Patrizia Cossutta

Giorgio Ripa

Carlo Felice Viscardi

Marcella Murru

Marina Ausonio

Alessandro Scala

Chiara Scotti

A process for the preparation of complexes of macrocyclic chelants with paramagnetic metal trivalent ions of formula (XII) ##STR1## wherein R.sub.1, R.sub.2 and Me.sup.3+ are as described in the following, comprising: a) reaction of 1,4,7,10-tetraazacyclododecane with triethyl orthoformate to give 5H,9bH-2a,4a,7,9a-octahydrotetraazacycloocta[cd]pentalene; b) carboxymethylation reaction in water; c) hydrolysis reaction in basic conditions; d) alkylation according to known methods with an epoxide in water; e) complexation according to known methods carried out in water by addition of a paramagnetic metal salt; f) purification by diafiltration, final desalting of the aqueous solution on ion exchange resins and g) crystallization or recovery.

Process for preparation of macrocyclic chelants and the chelates thereof

Process for the preparation of macrocyclic chelants and the chelates

A process for the preparation of complexes of macrocyclic chelants with paramagnetic metal trivalent ions of formula (XII) ##STR1## wherein R.sub.1, R.sub.2 and Me.sup.3+ are as described in the following, comprising: a) reaction of 1,4,7,10-tetraazacyclododecane with triethyl orthoformate to give 5H,9bH-2a,4a,7,9a-octahydrotetraazacycloocta�cd!pentalene; b) carboxymethylation reaction in water; c) hydrolysis reaction in basic conditions; d) alkylation according to known methods with an epoxide in water; e) complexation according to known methods carried out in water by addition of a paramagnetic metal salt; f) purification by diafiltration, final desalting of the aqueous solution on ion exchange resins and g) crystallization or recovery.

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Milan, Italy

Patrizia Cossutta