Cycloalkyl triamine pentacarboxylate as ligands for paramagnetic metal complexes

Abstract

A cycloalkyl triamine pentacarboxylate compound coordinating to a metal ion to form a high stability metal complex in serum is provided. The metal complex of the present invention can be used as a contrast agent for magnetic resonance imaging (MRI).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a synthetic scheme of cycloalkyl triamine pentacarboxylate compound according to a preferred embodiment of the present invention;

FIG. 2 is a potentiometric titration curve for cycloalkyl triamine pentacarboxylate compound according to a preferred embodiment of the present invention measured by an automatic titrator system;

FIG. 3 is a diagram showing the relative water proton paramagnetic longitudinal relaxation rates vs. time for the cycloalkyl triamine pentacarboxylate compound with the zinc (II) according to a preferred embodiment of the present invention; and

FIG. 4 is a diagram showing the ¹⁷O-NMR chemical shift of the cycloalkyl triamine pentacarboxylate compound according to a preferred embodiment of the present invention.

Claims

1. A cycloalkyl triamine pentacarboxylate compound represented by a formula (I):

2. The compound according to claim 1, wherein n is an integer from 1 to 3.

3. The compound according to claim 1, wherein A1, A2 and A3 are ones selected from the group consisting of methyl, benzyl, 2-methyoxybenzyl, diphenylmethyl, isothiocyanato-benzyl and 3,5-diiodo-4-hydroxybenzyl.

4. A metal complex serving as a contrast agent for magnetic resonance imaging (MRI) and represented by a formula ML, wherein M is a central metal ion selected from the group consisting of lanthanide series ions, manganese ion, iron ion, cobalt ion, copper ion, nickel ion, and chromium ion; and L is a ligand with a compound represented by a formula (I):

5. The metal complex according to claim 4, wherein the central metal ion is one selected from the group consisting of gadolinium ion, iron ion, and manganese ion.

6. The metal complex according to claim 4, wherein n is an integer from 1 to 3.

7. The metal complex according to claim 4, wherein A1 is one selected from the group consisting of methyl, isothiocyanato-benzyl and 3,5-diiodo-4-hydroxybenzyl.

8. The metal complex according to claim 4, wherein either one of A2 and A3 is one of benzyloxymethyl and hydrogen.