EP0794799A2

EP0794799A2 - Use of metal complexes as liver and gall bladder radiodiagnosis agents in computer tomography

Info

Publication number: EP0794799A2
Application number: EP95936963A
Authority: EP
Inventors: Franz-Karl Maier; Michael Bauer; Werner Krause; Ulrich Speck; Gabriele Schuhmann-Giampieri; Andreas Mühler; Thomas Balzer; Wolf-Rüdiger Press
Original assignee: Schering AG
Current assignee: Bayer Pharma AG
Priority date: 1994-11-30
Filing date: 1995-11-20
Publication date: 1997-09-17
Also published as: NO972457D0; NO972457L; FI972286A; JPH11503405A; US5672335A; NO972459D0; CZ166897A3; CN1167444A; MX9703880A; HUT77284A; FI972288A0; NO972460D0; US5885548A; EP0794939A1; IL116208A0; AU3922795A; AU4254696A; JPH10509961A; CA2206522A1; FI972287A0

Abstract

Metal complexes consisting of a metal of atomic number 39-42, 44-51 or 56-83, and a complexing agent are used to produce X-ray contrast media for use in enhanced-contrast computed tomography of the liver and the bile ducts.

Description

Use of metal complexes as

Liver and Gailen X-ray diagnostics in computer tomography

The invention relates to the use of metal complexes in liver and biliary X-ray diagnostics by means of X-rays, in particular in the

Computed Tomography.

The early detection of focal liver diseases, especially liver metastases and liver tumors, is one of the most important diagnostic problems in oncology. Four imaging methods are available for this: scintigraphy, ultrasonography, computed tomography and magnetic resonance imaging. Each of the methods has specific advantages and disadvantages, none is optimal in its own right, and practically every method would benefit from the presence of specific, compatible, intravenously administrable contrast agents [Harned, RK, Chezmar, JL, Nelson, RC : Imaging of patients with potentially resectable hepative neoplasms. AJR 159, 1191-1194 (1992)].

Scintigraphy offers a spatial resolution that is too low and its use is limited by the insufficient or too high specificity of the radiopharmaceuticals (which can only be used for a few types of tumor), so that it is not mentioned in the review article mentioned. Sonography is also currently not a sufficiently reliable technique for the detection of solid focal liver changes, since these often do not change in their acoustic properties differentiate sufficiently from the healthy liver tissue. Smaller lesions in the liver tissue can only be detected intraoperatively after exposing the liver and when using high-frequency transducers. Magnetic resonance imaging (MR) is able to record the entire liver with good spatial resolution and, depending on the measurement mode, also with good tissue differentiation. For MR, intravenously administrable, well-tolerated, effective contrast agents are in clinical trials that will further improve the benefits of this imaging method. Disadvantages, however, are movement artifacts in the high-resolution measuring methods, which last a few minutes, and the high costs of the devices themselves, which restrict their availability.

Computer tomography (CT) is actually the ideal technique for liver diagnostics. With modern devices, the entire liver can be captured within about 30 seconds with excellent spatial resolution. A single liver layer takes about 1 second, so movements through breathing and peristalsis hardly play a role. The cost of CT is significantly lower than that of MR. The disadvantage of the low

However, tissue density resolution must be compensated for by contrast media. With the contrast media clinically available today there are the following options:

1. The contrast media are injected or infused rapidly and in high doses (50-200 g) intravenously. For a few minutes there may be a difference in contrast between the lesion and normal liver tissue due to differences in perfusion, the relative blood volume of the tissue and the extracellular space. This period of time can only be achieved with the modern, very fast CT

Use unequal distribution of contrast media for diagnostics.

2. 4 - 6 hours after the administration of at least 120 g of the usual urographic contrast agents, in a very small number of patients an improved contrast between the healthy liver parenchyma that absorbs the contrast agent and the mostly non-absorbing focal ones Liver lesions observed. However, this technique, known as a late scan, is not sufficiently reliable and meaningful, so that it is not used routinely.

3. For arterial portography, a catheter e.g. into the mesenteric artery, the patient is then brought to the CT scanner and the

Scan performed during the infusion of approximately 150 ml of contrast medium. This technique is invasive, time-consuming and expensive, but currently provides the safest information about the presence and location of liver metastases. This information is of crucial importance for the decision about the resectability of metastases. The CT with arterial portography is therefore performed regularly preoperatively despite the effort.

The problems described above arise because the X-ray contrast media available today are intrinsically urographic products that do not accumulate in the liver. In order to nevertheless create some contrast, the liver is briefly flooded with very large amounts of contrast medium through the bloodstream

("dynamic scan") or an attempt is made to use the 1 - 2% of the contrast medium which is found in some of the patients in the liver parenchyma at a later point in time ("late scan").

It is easy to see that there is a need for improved diagnosis of focal liver lesions because the existing methods are too inefficient, too expensive or too burdensome for the patient. Therefore, there have been countless attempts over the decades to develop intravenous liver-specific X-ray contrast media. Only a few of the large number of tested preparations should be mentioned (see also Tab. 1-2): Thorotrast (colloidal

Suspensions of thorium oxide) provided excellent liver contrast, but was not excreted. The thorium α-emitter caused liver tumors decades after application. Schering brought the preparation in 1940

Hepatoselectan on the market, an emulsion of the finest droplets of a triiodinated oil. It had to be withdrawn from the market due to acute side effects. Successor products from other companies and research groups (EOE-13, AG-60-99 etc.) were abandoned during the clinical trials because of the same problems.

In addition to a large number of pharmaceutical problems, all particulate preparations (suspensions, emulsions, liposomes) have the disadvantage of causing characteristic side effects which are difficult to avoid and which are characteristic of high doses (5-20 g) for X-ray diagnostics. In the 1970s and early 1980s, great efforts were therefore made to find water-soluble X-ray contrast media that accumulate in the liver - sufficient for CT. Such substances were provided with up to 6 iodine atoms per molecule and not least because of this in animal experiments such. T. very effective and were well tolerated. There were striking differences in the effectiveness of the individual animal species. To date, however, none of the tested iodine-containing water-soluble contrast agents in humans has reached a sufficient concentration in the liver that would make a development for CT appear promising. A characteristic example of the many failed attempts was made by Mützel, W., Wegener OH, Souchon, R. and Weinmann, H.-J., Water-soluble contrast agents for computed tomography of the liver. experimental studies in dog. In Amiel (βdt): Contrast media in radiologiy, Lyon 1981, Springer Verlag Berlin Heidelberg New York 1982, pp. 320-323, Tab. 1. In this case too, in contrast to many animal species, adequate liver contrast was not found in humans.

Intravenous cholegraphics such as lotroxinate and loglycamat selectively accumulate in the liver. However, this process is very limited in capacity. With a concentration corresponding to 5 μg iodine / ml plasma, the 5-fold concentration in the liver is still reached, with a concentration of 50 μg iodine / ml only barely twice the concentration, with 500 μg iodine / ml plasma this is

Concentration in the liver is clearly lower than in plasma and therefore largely diagnostically worthless, since it is impossible to differentiate between actively enriching tissue and mere perfusion. However, computed tomography only detects iodine concentrations from approx. 1 mg / ml with sufficient certainty (Speck, U., Mützel, W., Herz-Hübner, U., Siefert, HM Pharmacology of lotroxinic acid, a new intravenous cholegraphic agent I. Pharmacokinetics and radiology in the animal, Drug. Res. 28, 2143-2149 (1978). It must therefore be stated that there is a need for stable, tolerable, preferably water-soluble and therefore pharmaceutically well characterized,

X-ray contrast media that are specific and not effective in too high a dose, and so far, despite decades of efforts, there is not a single product on the market or even in a promising stage of the clinical trial. Such preparations are difficult to find due to the unpredictable species dependence of absorption, enrichment and excretion by the liver by means of animal experiments; In addition, after many disappointing results in animal experiments, animal findings are no longer to be regarded as an indication of the suitability or inappropriateness of a substance or class of substances.

Metallic contrast agents for magnetic resonance imaging also absorb X-rays. Attempts were therefore made in individual cases, these substances to use for computed tomography (sign, HH et al .: gadolinium DTPA (Magnevist ^®) as a contrast agent for arterial DSA. Fortschr.

Röntgenstr. 160: 218-221 (1994); Quinn, A.D. et al .: Gd-DTPA: An alternative contrast medium for CT. J. Comput. Assist. Tomogr. 18, 634-636 (1994)). It has to be taken into account that the metal complexes available so far bind only one contrasting metal ion per molecule, while the iodinated X-ray contrast media contain 3 or 6 iodine atoms. Despite higher effectiveness of some metal ions against iodine (Zwicker, C., Langer, M., Langer, R., Keske, U. Comparision of iodinated and noniodinated contrast media in computed tomography. Invest. Radiol. 26, 162-164 (1991) the iodinated contrast agents have so far not been replaced by metal chelates in any relevant indication, a major disadvantage of using metal chelates as

X-ray contrast medium is the much lower content of X-ray absorbing element in the molecules (iodinated X-ray contrast medium: 3 or 6 iodine atoms / molecule; MR contrast medium: 1 metal ion / molecule). The contrast is correspondingly weak, so that the metal complexes are almost only for

experimental investigations in X-ray were used. Low concentrations of the metal ions are sufficient in MR because they are fast Exchanging protons of the water influence, while the X-ray must make the metal itself visible.

The object of the present invention is therefore to select from the known pharmaceutical substances suitable for imaging diagnosis on the basis of metal chelates those which are suitable for the production of contrast media for X-ray diagnosis, in particular computer tomography, the liver and biliary tract.

The object is achieved by the present invention, as shown in the

Claims are marked. The invention therefore relates to the objects characterized in the claims.

It has been found that metal complexes, consisting of a metal of atomic numbers 39-42, 44-51 or 56-83 and a complexing agent, for the production of contrast media for use in contrast-enhanced

Computer tomography of the liver and biliary tract are suitable.

It was surprising that with certain groups of metal chelates, despite clearly poorer conditions on the part of the radiation-absorbing effect per molecule, an absorption of the X-rays in the liver which was completely satisfactory for computer tomography was achieved for the first time in humans, without the need to use doses as high as this is the case with the non-specific iodinated X-ray contrast media. At the same time, it was shown that the accumulation in the liver takes place quickly and lasts for a sufficiently long time for the computed tomographic diagnostic method. The administration can be non-vasiv intravenously. The tolerance is excellent in the necessary dose range.

Acidic metal complexes with a molecular weight below 1500 D are generally suitable which contain at least one metal ion with the atomic number 39-42, 44-51 or 56-83 which is suitable for X-ray absorption. Those complexes are preferred which contain at least one lipophilic structural element, consisting of at least three carbon atoms, in the molecule. The total lipophilicity (determined as partition coefficient butanol / Tris buffer pH 7.6> 0.0002) of the complex must be higher than that of Gadolinium-DTPA. The complex formation constant must also exceed 10 ¹⁴ . Such substances and their preparation are described in the examples of this application and in EP 0405 704; EP 0230893; US 4,880,008; US 4,899,755; US 5,250,285 and US 5,318,771.

The following publications and the literature cited therein provide the person skilled in the art with additional information about the reaction conditions required in the preparation of the compounds according to the invention:

● Production of ethers, especially phenol ethers:

Houben-Weyl, Volume VI / 3, Part A, Georg Thieme Verlag, Stuttgart, 1965

● Production of amines, in particular amino acid derivatives:

Houben-Weyl, Volume XI / 1, Georg Thieme Verlag, Stuttgart, 1957,

Houben-Weyl, Volume XI / 2, Georg Thieme Verlag, Stuttgart, 1958

● Production of alkyl halides:

Houben-Weyl, Volume V / 3, Georg Thieme Verlag, Stuttgart, 1962

Houben-Weyl, Volume V / 4, Georg Thieme Verlag, Stuttgart, 1960

● Production of carboxylic acids and carboxylic acid derivatives:

Houben-Weyl, Volume VIII, Georg Thieme Verlag, Stuttgart, 1952

● Production of sulfonic acid derivatives:

Houben-Weyl, Volume IX, Georg Thieme Verlag, Stuttgart, 1955

● Reductive amination:

C.F. Lane, Synthesis 135 (1975)

Production of DTPA derivatives:

M.A. Williams, H. Rapoport, J.Org.Chem, 58, 115nd carboxylic acid derivatives:

Preferred substances according to the invention are described by the general formulas I to XIII: Formula I.

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

k represents the numbers 0, 1 or 2 and

R ¹ independently of one another represents a hydrogen atom or a radical of the formula Ia

wherein

m, p stands for the numbers 0 or 1

R ² independently of one another represents a hydrogen atom or a branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ -C ₁₀ - alkylene chain which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted,

where if m and / or p is zero, two or more heteroatoms must not be directly connected to one another and where free carboxyl groups not used for complexation can also be present as salts of physiologically compatible cations or as an amide of the formula

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

Formula II

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1 R ¹ independently of one another represents a hydrogen atom or a branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

if m and / or p is zero, two or more heteroatoms must not be directly connected to one another,

wherein the six-membered carbon rings present in formula II can also be aromatic and

where free carboxyl groups not used for complexation can also be present as salts of physiologically compatible cations or as an amide of the formula

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

Formula III

wherein X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

wherein the six-membered carbon ring present in formula III can also be aromatic and

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has. Formula IV

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ -C ₁₀ - alkylene chain which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted, if m and / or p is zero, two or more heteroatoms must not be directly connected to one another,

wherein the six-membered carbon rings present in formula IV can also be aromatic and

wonn

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

Formula V

wonn

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

wherein the six-membered carbon ring present in formula V can also be aromatic and

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a radical of the formula Ia. Formula VI

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ - C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ -C ₁₀ - alkylene chain, which may be replaced by an oxygen or a

Sulfur atom, an -N (H) - or an -N (R ² ) - group is interrupted,

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

Formula VII

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

k represents the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1 R ² independently of one another represents a hydrogen atom or a branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

where if m and / or p is zero, two or more heteroatoms must not be directly connected to one another and

wherein

R ^{1 has} the meaning given above and

Ar independently of one another represents a saturated or unsaturated, optionally bicyclic, C ₅ -C ₁₀ ring which is optionally interrupted by one or two oxygen, sulfur and / or nitrogen atoms and

optionally by one to three phenyl, pyridyl, HO, HS,

HOOC, R ¹ OOC, R ¹ O, R ¹ NHOC, R ¹ CONH, R ¹ and / or H ₂ N groups is substituted,

which further optionally contains one to three carbonyl, thiocarbonyl and / or imino groups and and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has. Formula VIII

wherein

independently represents a hydrogen atom or a metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83

stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

wherein

R ^{1 has} the meaning given above and

optionally by one to three phenyl, pyridyl, HO, HS,

at least one of the radicals denoted by R ^{1 has} the meaning of a radical of the formula Ia.

Formula IX

wonn X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83,

y stands for the number zero or one and

R ^{3 represents} a C ₁ -C ₅ alkyl radical or a benzyl radical.

Formula X

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of atomic numbers 39-42, 44-51 or 56-83,

R ^{3 represents} a methyl, ethyl, n-propyl, n-butyl or a benzyl radical.

Formula XI

independently of one another represents a hydrogen atom or a metal ion equivalent of an element of atomic numbers 44-51 or 56-83, one of the radicals R ^{1 represents} a radical of the formula -CH ₂ -C ₆ H4- (O) _r -R ² , in which the aromatic ring can be substituted in the ortho, meta or para position and the other radical R ^{1 represents} hydrogen stands,

R ² for a hydrocarbon radical consisting of 1-6

Carbon atoms and 0-2 oxygen atoms, a phenyl or a benzyl radical or represents hydrogen and r represents the numbers zero or one,

in which carboxyl groups can also be present as amides,

together with those required for charge balancing

physiologically acceptable cations.

Formula XII

wherein

R ^{1 represents} a radical of the formula Ib

wherein

p stands for the number 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical,

R ^{3 represents} a hydrogen atom or a branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical or a

Carboxyl group,

L ^{1 stands} for a direct bond or a C ₁ -C ₄ alkylene chain, L ² , L ³ each independently of one another for a direct bond

Oxygen atom, a sulfur atom or a C ₁ -C ₁₀ alkylene chain which is optionally interrupted by one to three oxygen and / or one to three sulfur atoms, whereby two or more heteroatoms must not be directly connected to one another and

X ¹ independently of one another for a group

OX ² with X ² in the meaning given below or for a group

N (R ⁴ ) R ⁵ wherein

R ⁴ , R ⁵ independently of one another represent a hydrogen atom or a group R ¹ or

R ⁴ and R ⁵ together, including the common amide nitrogen atom, form a four- to eight-membered ring which can contain two further oxygen atoms and / or two carbonyl groups,

X ² independently of one another represents a hydrogen atom or a metal ion equivalent of an element of atomic numbers 39-51 or 57-83, in combination with the physiologically compatible inorganic and / or organic cations which may be required for charge balancing.

Formula XIII

wherein

5, 6 or 7 of the radicals denoted by R ¹ are hydrogen and the others independently of one another are a radical of the formula Ic

wherein

p stands for the number 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical,

Carboxyl group,

L ¹ represents a direct bond, a sulfur atom, a C ₁ -C ₄ alkylene chain or an interrupted by a sulfur atom C ₁ -C ₄ - alkylene chain,

L ² , L ³ each independently for a direct bond

Oxygen atom, a sulfur atom or a C ₁ -C ₁₀ alkylene chain which optionally contains one to three oxygen and / or one to three sulfur atoms, where if p is zero two or more heteroatoms must not be directly connected to one another and

X ¹ independently of one another for a group

OX ² with X ² in the meaning given below or for a group

N (R ⁴ ) R ⁵ wherein

R ⁴ , R ⁵ independently of one another represent a hydrogen atom or a radical R ¹ or

The symbol

stands for a C ₆ ring which can be saturated, unsaturated or aromatic and which is substituted n times with the group R ¹ . The following are examples of radicals of the general formulas Ia, Ib and Ic:

Benzyl, methoxybenzyl, ethoxybenzyl, propoxybenzyl, isopropoxybenzyl, butoxybenzyl, isobutoxybenzyl, tert.-butoxybenzyl, pentoxybenzyl,

Benzyloxybenzyl, methylbenzyl, ethylbenzyl, propylbenzyl, butylbenzyl, pentylbenzyl and benzylbenzyl radicals. Preferred radicals are the methoxybenzyl, ethoxybenzyl and the butylbenzyl radical, the is particularly preferred

Ethoxybenzyl group.

Of the metal ions, the lanthanides are preferred. In measurements under practical conditions (see Example 1), holmium, erbium and ytterbium have proven to be more suitable than the elements gadolinium and dysprosium common in MR. Thulium seems less suitable from an economic point of view because of the high price, but is basically also suitable. The elements lutetium praseodymium, bismuth, lead and hafnium are also suitable. Other elements of the ordinal numbers mentioned in claim 1 can also be used.

It is often the case that the complexing agent has more acid functions than the complexed metal carries positive elementary charges. For example, the 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (4-ethoxybenzyl) -undecanedioic acid described in Example 1 carries five acid groups, while the dysprosium in the dysprosium oxide (Dy ₂ O ₃ ) is in the oxidation state + III. In the

Complex formation is thus neutralized only three of the five protons of the acid. A complex is thus formed which also contains two dissociable protons, an acid complex. Two protons and one dianion - formed from the metal and the complexing agent - are thus present in aqueous solution. For many

For purposes it is advantageous to exchange the protons for other physiologically compatible cations (neutralization) so that a salt is formed. Examples of physiologically compatible cations are sodium ⁺ , calcium ²⁺ ,

Magnesium ²⁺ and zinc ²⁺ as well as organic cations of the bases meglumine,

Called glucosamine, arginine, omithine, lysine and ethanolamine. The following compounds are particularly suitable for the use according to the invention:

Gadolinium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

● ytterbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Praseodymium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

● cerium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) undecanedioic acid,

Lutetium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Lead (II) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) undecanedioic acid,

Bismuth (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Lanthanum (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

● Dysprosium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Erbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

● terbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

● Holmium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Praseodymium (III) complex of 3,6,9-triaza-3,6,9-tristcarboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Hafnium (IV) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid,

Bismuth (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxy-benzyl) -undecanedioic acid, ● ytterbium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -5- {4- [2- (2-ethoxyethoxy) ethoxy] benzyl} undecanedioic acid,

● ytterbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (2-ethoxy-benzyl) -undecanedioic acid,

Gadolinium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

● ytterbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

Praseodymium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

Hafnium (IV) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

Bismuth (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

Lutetium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) -undecanedioic acid,

Lead (II) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-butyl-benzyl) undecanedioic acid,

● Bismuth complex of 3,6,9-triaza-3,9-bis (carboxymethyl) -6- {2- [4- (1,4,7-trioxaoctyl) phenyl] -1-carboxyethyl} -4.8-bis - [4- (1,4,7-trioxaoctyl) benzyl] undecanedioic acid,

● ytterbium (III) complex of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Lanthanum (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

● cerium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Praseodymium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Gadolinium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis (4-ethoxybenzyl) -undecanedioic acid, ● terbium (III) complex of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

● dysprosium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis (4-ethoxybenzyl) -undecanedioic acid,

Holmium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Erbium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

● terbium (III) complex of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Lutetium (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Hafnium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

● tantalum (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Lead (II) complex of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Bismuth (III) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid,

Gadolinium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -undecanedioic acid,

● Hafnium complex of 3,6,9-triaza-3,9-bis (carboxymethyl) -6- {2- [4- (carboxymethoxy) phenyl] -1-carboxyethyl} -4- [4-propoxybenzyl] undecanedioic acid ,

● Terbium complex of 3,6,9-triaza-6- (carboxymethyl) -3,9-bis- [2- (4-methoxyphenyl) -1-carboxyethyl] -2,10-bis- (4-methoxybenzyl) -undecanedioic acid ,

● Holmium complex of 3,6,9-triaza-6,9-bis (carboxymethyl) -3 - {(4-methoxybenzyl) carboxymethyl] -10- (4-ethoxybenzyl) -2- (4-methoxybenzyl) - undecanedioic acid

● Erbium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -4,8-bis- (4-propoxybenzyl) -undecanedioic acid ● Dysprosium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (4-ethoxybenzyl) -undecanedioic acid and

● Ytterbium complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (benzylmethyl) - undecanedioic acid

and their salts and amides.

The metal complexes mentioned are preferably used in the form of their sterile aqueous solutions. In addition to the metal complexes which absorb the X-rays, they can contain the usual pharmaceutical auxiliaries, such as buffers, bases, acids, stabilizers, solubilizers, and substances for

Adjustment of the osmolality and viscosity, pharmacologically active additives and an excess (0.1 to 10 mol% based on the diagnostically active metal complex) of free complexing agent or its salts / complexes with weakly bound physiologically compatible ions such as calcium ²⁺ ,

Contain magnesium ²⁺ and zinc ²⁺ to improve the excretion of heavy metal ions. Suitable substances and their concentration ranges are known to the person skilled in the art or can be found in the literature.

The metal complexes are preferably used in a concentration of 0.1 mol to 1.0 mol based on the contrasting metal ion. Higher or lower concentrations are possible depending on the requirements and the solubility of the compounds in question. The dosage for contrast enhancement in the liver is approximately 0.1-1.5 mmol / kg body weight, the range 0.2-0.6 mmol / kg is preferred.

The administration can take place in the usual ways in medicine.

Intravenous infusion or injection over a period of about 1 minute to 30 minutes is preferred. In summary, it can be stated that the substance class described here has for the first time been able to achieve a specific contrast medium concentration in the liver in humans, that which is available today computed tomography technique to a useful diagnostic

Information leads. This finding is all the more surprising than

♦ For decades, preparations for this purpose have been searched in vain,

♦ the iodized X-ray contrast media did not meet the requirements despite the presence of all theoretically required molecular properties and a significantly higher content of contrasting element in the molecule, ♦ the effect of the substances according to the invention in magnetic resonance tomography already occurs at concentrations 10 times lower than for X-rays Computer tomography is required and that these lower concentrations of a large number of x-ray contrast media are also achieved in the liver of humans, without these x-ray contrast media therefore being able to be used for computer tomography, MR or another imaging method for improving the diagnosis of focal liver changes,

♦ Animal experiments have so far proven to be completely unreliable with regard to the suitability of contrast media for contrast enhancement in computer tomography of the liver.

In summary, it follows that the use of the metal complexes mentioned according to the invention is an excellent aid for computer tomographic diagnosis, in particular of the liver and bile.

The following examples serve to illustrate the invention without wishing to restrict the subject matter to it.

example 1

Dysprosium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (4-ethoxybenzyl) -undecanedioic acid a) N-benzyl-tyrosine tert-butyl ester

16.9 g (71.5 mmol) of tyrosine tert-butyl ester and 8.33 g (78.6 mmol) of benzaldehyde are stirred in 50 ml of methanol at 24 ° C for 3 hours and then with 3.37 g (53.6 mmol ) Sodium cyanoborohydride added. After stirring for 24 hours at room temperature, the mixture is adjusted to pH 2 by carefully adding half-concentrated hydrochloric acid, then with concentrated aqueous

Sodium hydrogen carbonate solution neutralized and after extensive

Evaporate methanol with ethyl acetate. The

organic phase is dried over anhydrous magnesium sulfate, filtered and evaporated. The residue is on silica gel

Chromatographed diethyl ether / hexane / triethylamine; the product-containing

Fractions are pooled and evaporated.

Yield: 15.7 g (67% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 73.37 H 7.70 N 4.28 0 14.66

found: C 73.25 H 7.84 N 4.16

b) N-Benzyl-2- (4-hydroxybenzyl) -3-azaglutaric acid di-tert-butyl ester

15.1 g (46.1 mmol) of N-benzyl-tyrosine tert-butyl ester (Example a) are dissolved in 50 ml of tetrahydrofuran and mixed with 5 ml of water and 9.54 g (69 mmol)

Potassium carbonate added. After the dropwise addition of 9.89 g (51 mmol) of bromoacetic acid tert-butyl ester is stirred at 65 ° C for two days. After cooling, the mixture is filtered, concentrated in vacuo and the residue is chromatographed on silica gel with diethyl ether / hexane / triethylamine. The product fractions are evaporated in a vacuum and dried.

Yield: 14.9 g (73.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 74.33 H 8.22 N 3.94 0 13.50

Found: C 74.27 H 8.26 N 3.74

c) N-Benzyl-2- (4-ethoxybenzyl) -3-azaglutaric acid di-tert-butyl ester

13.2 g (30 mmol) of N-benzyl-2- (4-hydroxybenzyl) -3-azaglutaric acid di-tert-butyl ester (example b) are dissolved in 50 ml of anhydrous N, N-dimethylformamide and at 0 ° C under argon 1.31 g (33 mmol) of sodium hydride dispersion (60% in mineral oil) were added. The mixture is allowed to stir for 15 minutes, 8.05 g (51.7 mmol) of ethyl iodide are then added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further three hours. For working up, the mixture is taken up in toluene and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is chromatographed for purification on silica gel with hexane / diethyl ether / triethylamine. The

Product fractions are evaporated in a vacuum and dried.

Yield: 12.7 g (90.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 71.61 H 8.37 N 2.98 0 17.03

Found: C 71, 72 H 8.43 N 2.87 d) 2- (4-ethoxybenzyl) -3-azaglutaric acid di-tert-butyl ester

14.2 g (30.2 mmol) of the compound prepared according to Example c) are dissolved in 75 ml of ethanol and after the addition of 1.4 g of palladium (10%) on activated carbon under a hydrogen atmosphere at room temperature until the end

Hydrogen uptake hydrogenated. After filtering and evaporating the filtrate in vacuo, a colorless oil is obtained.

Yield: 11.3 g (98.6% of theory)

Analysis (based on solvent-free substance):

calc .: C 66.46 H 8.77 N 3.69 0 21.08

Found: C 66.44 H 8.63 N 3.57

e) 3,6-Diaza-3- (tert-butoxycarbonylmethyl) -6- (2-hydroxyethyl) octanedioic acid di-tert-butyl ester

20.8 g (200 mmol) of N- (2-hydroxyethyl) ethylenediamine are mixed with 128.55 g (660 mmol) of tert-butyl bromoacetate and 124.4 g (900 mmol) of potassium carbonate in tetrahydrofuran / water analogously to Example b) implemented. After chromatographic purification, the title compound is obtained as a colorless oil.

Yield: 82.7 g (92.6% of theory)

Analysis (based on solvent-free substance):

calc .: C 59.17 H 9.48 N 6.27 025.08

found: C 59.24 H 9.60 N 6.13

f) 3,6-Diaza-3- (tert-butoxycarbonylmethyl) -6- (2-bromethyl) octanedioic acid di-tert-butyl ester

A solution of 33.8 g (75.8 mmol) of the compound described in Example e) and 22.9 g (87.1 mmol) of triphenylphosphine in 400 ml of dichloromethane is at 0 ° C 15.5 g (87.1 mmol) of N-bromosuccinimide were added in portions and

then stirred for 20 hours at room temperature. The solution is evaporated and the residue is extracted with tert-butyl methyl ether. A precipitate is formed, which is separated off and washed with tert-butyl methyl ether. The combined filtrates are evaporated and the residue is chromatographed on silica gel with hexane / diethyl ether. Evaporation of the product fractions gives a colorless oil.

Yield: 31.3 g (81.0% of theory) Analysis (based on solvent-free substance):

calc .: C 51.87 H 8.11 Br 15.68 N 5.50 0 18.84

Found: C 51.69 H 8.20 Br 15.51 N 5.43

g) 3,6,9-Triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -2- (4-ethoxybenzyl) -undecanedioic acid di-tert. -butyl ester

7.59 g (20 mmol) of the compound prepared according to Example d) and 11.2 g (22 mmol) of 3,6-diaza-3- (tert-butoxycarbonylmethyl) -6- (2-bromethyl) octanedioic acid di Tert-butyl ester (Example f) are placed in 45 ml of acetonitrile and mixed with 25 ml of 2N phosphate buffer solution (pH 8.0). The mixture is stirred vigorously at room temperature for 22 hours, the aqueous phosphate buffer phase being replaced with fresh buffer solution after 2 and 7 hours. Then the organic phase is evaporated in vacuo and the residue on silica gel

Chromatographed hexane / ethyl acetate / triethylamine. The product-containing fractions are evaporated in vacuo.

Yield: 13.3 g (82.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 63.92 H 9.11 N 5.20 021.78

found: C 64.07 H 9.20 N 5.08 h) 3,6,9-Triaza-3,6,9-tris (carboxymethyl) -2- (4-ethoxybenzyl) -undecanedioic acid

12.6 g (15.6 mmol) of the pentaester described in Example g) are dissolved in 50 ml of methanol and 40 ml of 2N sodium hydroxide solution are added. The mixture is boiled under reflux for three hours, the methanol is stripped off in vacuo and the mixture is stirred at 60 ° C. for a further two hours. The pH is then adjusted to 1 using concentrated hydrochloric acid, the mixture is evaporated to dryness in vacuo and the residue is stirred with isopropanol. After filtering and evaporating the filtrate in vacuo, a colorless solid is obtained.

Yield: 7.5 g (91.1% of theory)

Analysis (based on anhydrous substance):

calc .: C 52.37 H 6.31 N 7.97 0 33.36

Found: C 52.24 H 6.45 N 7.81

i) Dysprosium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (4-ethoxybenzyl) -undecanedioic acid 6.9 g (13 mmol) of the pentic acid described in Example h) are taken up in 30 ml of water, 2.42 g (6.5 mmol) of dysprosium oxide are added and the mixture is stirred at 85 ° C. for eight hours. The pH is then adjusted to 7.2 with dilute sodium hydroxide solution, and the filtrate is filtered and freeze-dried.

Yield: 8.45 g (88.9% of theory) of colorless lyophilisate.

Analysis (based on solvent-free substance):

Calc .: C 37.79 H 3.86 Dy 22.23 N 5.75 Na 6.29 024.08

Found: C 37.64 H 3.97 Dy 22.12 N 5.62 Na 6.04 Example 2

Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -2- (benzylmethyl) -undecanedioic acid a) 3,6,9-triaza-2- (benzylmethyl) -nonanoic acid benzyl ester

13.4 g (50.0 mmol) of benzyl 2-oxo-4-phenylbutyrate and 31.0 g (300 mmol) of diethylenetriamine are stirred in 200 ml of methanol for two hours at room temperature. Then 0.95 g (25.0 mmol) of sodium borohydride are added in portions at 0 ° C. The mixture is left to stir overnight

Reaction mixture gently in a vacuum. The residue is partitioned between dichloromethane and water, the organic phase is dried over sodium sulfate, filtered and evaporated. The residue is chromatographed on silica gel using dichloromethane / methanol / triethylamine (70: 30: 1) as the eluent. The fractions containing the pure product are combined and evaporated.

Yield: 13.5 g (75.9% of theory) of a pale yellow oil.

Analysis (based on solvent-free substance):

calc .: C 70.96 H 8.22 N 11.82 09.00

Found: C 70.88 H 8.41 N 12.04

b) 3,6,9-Triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -2- (benzylmethyl) -undecanedioic acid di-tert. -butyl ester

6.91 g (50.0 mmol) of potassium carbonate are dissolved in 7 ml of water and 3.55 g (10.0 mmol) of triamine from Example a) in 50 ml of tetrahydrofuran are added at 35 ° C. 9.75 (50.0 mmol) bromoacetic acid tert. -butyl ester is added dropwise and the mixture is stirred at 60 ° C. for three hours. After stirring for 15 hours at room temperature, the reaction mixture is mixed with a little water and extracted with ethyl acetate. The organic phase is over Dried sodium sulfate, evaporated and the residue on silica gel

(Ethyl acetate / acetone) chromatographed. After evaporation of the product-containing fractions, the pentaester is obtained as a colorless oil.

Yield: 6.64 g (81.8% of theory)

Analysis (based on solvent-free substance):

calc .: C 66.56 H 8.56 N 5.18 0 19.70

Found: C 66.79 H 8.32 N 4.93

c) Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -2- (benzylmethyl) -undecanedioic acid

15.6 g (19.2 mmol) of pentaester (from 3 batches corresponding to Example b)) are dissolved in 80 ml of methanol and reacted with 76.8 ml of 2N sodium hydroxide solution. The mixture is stirred at 55 ° C. for five hours, then the methanol is evaporated off, water is added and the mixture is evaporated again. You take up in water and make with acid

Ion exchanger to pH 1.9. After filtering off the exchanger, the aqueous solution is mixed with 3.79 g (9.61 mmol) of ytterbium oxide and stirred at 95 ° C. After complexation is complete, the mixture is filtered, adjusted to pH 7.2, stirred with 0.2 g of activated carbon at 90 ° C. for ten minutes, filtered again and the filtrate is lyophilized.

Yield: 12.8 g (93.8% of theory) of colorless lyophilisate. Analysis (based on anhydrous substance):

calc .: C 37.14 H 4.28 N 5.58 023.35 Yb 20.86 Na 6.10

Found: C 37.22 H 4.40 N 5.62 Yb 20.75 Na 6.03

Example 3

Bismuth complex of the disodium salt of 3,6,9-triaza-3,9-bis (carboxymethyl) -6- {2- {4- (1,4,7-trioxaoctyl) phenyl] -1-carboxyethyl} -4, 8-bis- [4- (1,4,7-trioxaoctyl) benzyl] undecanedioic acid a) N-Benzyloxycarbonyl-3- [4- (1,4,7-trioxaoctyl) phenyl] alanine methyl ester

6.59 g (20 mmol) of N-benzyloxycarbonyl-tyrosine methyl ester are dissolved in 25 ml of anhydrous N, N-dimethylformamide and 0.81 g (20.5 mmol) of sodium hydride dispersion (60% in mineral oil) are added at 0 ° C. under argon . The mixture is allowed to stir for 10 minutes, then 3.75 g (20.5 mmol) of 1-bromo-2- (2-methoxyethoxy) ethane are added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further three hours. The mixture is worked up in toluene

added and shaken several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is chromatographed for purification on silica gel with hexane / diethyl ether / triethylamine.

Yield: 7.6 g (88% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 64.02 H 6.77 N 3.25 025.96

found: C 64.13 H 6.59 N 3.11

b) N-Benzyloxycarbonyl-2-amino-2- [4- (1,4,7-trioxaoctyl) benzyl] ethanol

7.35 g (17 mmol) of N-benzyloxycarbonyl-3- [4- (1,4,7-trioxaoctyl) phenyl] alanine methyl ester (Example a) are dissolved in 35 ml of tert-butyl methyl ether and 9 g (23.8 mmol) of sodium borohydride were added. 10 ml of methanol are added at 5 ° C. and the mixture is stirred for four hours under argon at constant temperature.

Then 1.5 ml of acetic acid dissolved in 5 ml of tetrahydrofuran are added, 5 ml of water are added and the mixture is stirred for ten minutes at room temperature. The organic phase is separated off, washed with water and dried over sodium sulfate. The drying agent is suctioned off, the filtrate is evaporated and the residue is chromatographed on silica gel for purification.

Yield: 6.4 g (93.3% of theory) Analysis (based on solvent-free substance):

calc .: C 65.49 H 7.24 N 3.47 0 23.79

Found: C 65.34 H 7.32 N 3.36

c) 2-Amino-2- [4- (1,4,7-trioxaoctyl) benzyl] ethanol

6.3 g (15.6 mmol) of the compound prepared according to Example b) are dissolved in 35 ml of ethanol and after the addition of 0.6 g of palladium (10%) on activated carbon under a hydrogen atmosphere at room temperature to the end

Yield: 4.1 g (97.6% of theory) Analysis (based on solvent-free substance):

calc .: C 62.43 H 8.61 N 5.20 O 23.76

Found: C 62.26 H 8.67 N 5.04

d) N- {2-Hydroxy-1- [4- (1,4,7-trioxaoctyl) benzyl] ethyl} di-tert-butyl ester

3.9 g (14.5 mmol) of the compound described in Example c), 6.2 g (32 mmol) of bromoacetic acid tert. -butyl ester and 4.4 g (32 mmol) of potassium carbonate are stirred in 15 ml of tetrahydrofuran / water (2: 1) at 65 ° C for two days. After this

Cooling is filtered, concentrated in vacuo and the residue is chromatographed on silica gel with diethyl ether / hexane / triethylamine. The product fractions are evaporated in a vacuum and dried.

Yield: 6.1 g (84.5% of theory)

Analysis (based on solvent-free substance):

calc .: C 62.76 H 8.71 N 2.82 025.72

Found: C 62.59 H 8.88 N 2.80 e) Di- tert -butyl N- {2-bromo-1- [4- (1,4,7-trioxaoctyl) benzyl] ethyl} -iminodiacetic acid

A solution of 5.8 g (11.6 mmol) of the compound described in Example d) and 3.35 g (12.8 mmol) of triphenylphosphine in 50 ml of dichloromethane is added in portions with 2.28 g (12.8 mmol ) N-bromosuccinimide added and

Yield: 5.9 g (90.7% of theory)

Analysis (based on solvent-free substance):

calc .: C 55.71 H 7.55 Br 14.26 N 2.50 0 19.98

Found: C 55.62 H 7.39 Br 14.14 N 2.38

f) N-Benzyloxycarbonyl-3- [4- (1,4,7-trioxaoctyl) phenyl] alanine tert. -butyl ester

7.43 g (20 mmol) N-benzyloxycarbonyl-tyrosine tert. -butyl esters are reacted with 1-bromo-2- (2-methoxyethoxy) ethane to give the alkylated phenol in analogy to example a).

Yield: 8.2 g (86.6% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 65.94 H 7.45 N 2.96 023.65

Found: C 65.98 H 7.52 N 2.78 g) 3- [4- (1,4,7-Trioxaoctyl) phenyl] alanine tert-butyl ester

7.9 g (16.7 mmol) of the compound prepared according to Example f) are dissolved in 40 ml of ethanol and after the addition of 0.8 g of palladium (10%) on activated carbon under a hydrogen atmosphere at room temperature until the end

Yield: 5.5 g (97.0% of theory)

Analysis (based on solvent-free substance):

calc .: C 63.69 H 8.61 N 4.13 023.57

Found: C 63.57 H 8.71 N 4.05

h) 3,6,9-Triaza-3,9-bis (tert-butoxycarbonylmethyl) -6- {2- [4- (1,4,7-trioxaoctyl) phenyl] -1-tert-butoxycarbonylethyl } -4,8-bis- [4- (1,4,7-trioxaoctyl) benzyl] undecanedioic acid di-tert-butyl ester

5.2 g (15.3 mmol) of the amine prepared according to Example g) and 18.9 g (33.7 mmol) of the bromide prepared according to Example e) are placed in 65 ml of acetonitrile and mixed with 30 ml of 2N phosphate buffer solution (pH 8.0). The mixture is stirred vigorously at room temperature for 30 hours, the aqueous

Phosphate phase is exchanged for fresh buffer solution after 2, 8 and 18 hours. Then the organic phase is evaporated in vacuo and the residue is chromatographed on silica gel with hexane / ethyl acetate / triethylamine. The product-containing fractions are in a vacuum

evaporated.

Yield: 16.3 g (82.0% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 64.74 H 8.62 N 3.24 023.41

Found: C 64.58 H 8.70 N 3.29 i) Bismuth complex of the disodium salt of 3,6,9-triaza-3,9-bis (carboxymethyl) -6 {2- [4- (1,4,7-trioxaoctyl) phenyl] -1-carboxyethyl} -4 , 8-bis- [4- (1,4,7-trioxaoctyl) benzyl] -undecanedioic acid 15.9 g (12.2 mmol) of the compound prepared according to Example h) are dissolved in 65 ml of tetrahydrofuran and 75 ml more normal Sodium hydroxide solution is added, the mixture is stirred at 55 ° C. for four hours, the pH is adjusted to 1.3 with concentrated hydrochloric acid, the mixture is concentrated on a rotary evaporator and the residue is purified

Ion exchange chromatography (cation exchanger (H ⁺ form), eluent:

aqueous ammonia solution). The egg is evaporated and dried in a high vacuum, causing the free complexing agent to develop.

The penta acid is taken up in 250 ml of water and 6.22 g (12.2 mmol) of bismuth oxycarbonate are added. The suspension is stirred at 100 ° C. for 25 hours and filtered. The pH is then adjusted to 7.2 with a normal sodium hydroxide solution.

The solution is then stirred at 60 ° C for 1 hour after the addition of 1.6 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid.

Yield 14.7 g (95% of theory) Analysis (based on anhydrous substance):

calc .: C 47.36 H 5.25 N 3.31 023.97 Bi 16.48 Na 3.63

Found: C 47.21 H 5.44 N 3.26 Bi 16.27 Na 3.29

Example 4 Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis (4-ethoxybenzyl) -undecanedioic acid

a) 2- (4-Ethoxybenzyl) -2-aminoethanol 45.0 g (136.7 mmol) [2- (4-ethoxyphenyl) -1-hydroxyphenyl) ethyl] -carbamic acid benzyl ester (DE 4302287 A1), dissolved in 300 ml of ethanol, with 3.0 g Palladium (10%) added to activated carbon and hydrogenated until the hydrogen uptake has ended. The catalyst is then filtered off and the filtrate is evaporated to dryness.

Yield: 26.7 g (100% of theory) of a colorless solid.

Analysis (based on solvent-free substance):

calc .: C 69.28 H 7.04 N 4.25 0 19.43

found: C 69.25 H 7.11 N 4.13

b) N, N- [1 - (4-Ethoxybenzyl) -2-hydroxyethyl] iminodiacetic acid di-tert-butyl ester

20 g (102.4 mmol) of 2- (4-ethoxybenzyl) -2-aminoethanol (Example a) are tert with 40 g (205 mmol) of bromoacetic acid. butyl ester implemented in an analogous manner to Example 3d). After chromatographic cleaning, you can get it

Dialkylation product as a colorless oil.

Yield: 37.6 g (86.7% of theory)

Analysis (based on solvent-free substance):

calc .: C 65.22 H 8.81 N 3.31 0 22.66

Found: C 65.07 H 8.92 N 3.28

c) N, N- [2-bromo-1- (4-ethoxybenzyl) ethyl] iminodiacetic acid di-tert. -butyl ester By reacting 9.3 g (21.9 mmol) of the diester from Example b) with

Triphenylphosphine and N-bromosuccinimide in an analogous manner to Example 3e) gives the bromide as a pale yellow oil.

Yield: 8.9 g (83.5% of theory) Analysis (based on solvent-free substance):

calc .: C 56.79 H 7.46 Br 16.43 N 2.88 0 16.44

Found: C 56.63 H 7.50 Br 16.29 N 2.69

d) 3,6,9-triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -4,8-bis- (4-ethoxybenzyl) -undecanedioic acid di-tert. -butyl ester

1.4 g (8.5 mmol) glycine tert. -butyl ester hydrochloride and 8.5 g (17.5 mmol) of the bromide prepared according to Example c) are placed in 45 ml of acetonitrile and mixed with 20 ml of 2N phosphate buffer solution (pH 8.0). The mixture is stirred vigorously at room temperature for 28 hours, the aqueous phosphate buffer phase being exchanged for fresh buffer solution after 2, 8 and 16 hours. The organic phase is then evaporated in vacuo and the residue is chromatographed on silica gel. The product-containing fractions are evaporated in vacuo.

Yield: 5.3 g (66.2% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 66.29 H 8.88 N 4.46 020.38

Found: C 66.37 H 8.79 N 4.33

e) Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4,8-bis (4-ethoxybenzyl) -undecanedioic acid

4.7 g (5 mmol) of the penta-tert-butyl ester (Example d) are in 25 ml

Dissolved tetrahydrofuran and mixed with 20 ml of two normal sodium hydroxide solution, stirred for two hours at 50 ° C, adjusted to pH 1 with concentrated hydrochloric acid, concentrated vigorously on a rotary evaporator and cleaned the residue through

Ion exchange chromatography (cation exchanger (H ⁺ form), eluent: aqueous ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free ligand is obtained. The penta acid is taken up in 100 ml of water and 1.31 g (2.5 mmol) of ytterbium carbonate is added. The suspension is stirred at 60 ° C. for two hours and filtered. The pH is then adjusted to 7.2 with a normal sodium hydroxide solution.

The solution is then stirred at 50 ° C. for one hour after the addition of 0.5 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid.

Yield: 4.1 g (94% of theory)

Analysis (based on anhydrous substance):

calc .: C 43.89 H 4.37 N 4.80 0 21.92 Yb 19.76 Na 5.25

Found: C 43.71 H 4.47 N 4.63 Yb 19.58 Na 4.96

Example 5

Gadolinium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -undecanedioic acid a) 3,6,9-triaza-2,10 bis (4-ethoxybenzyl) -undecanedioic acid di-isopropyl ester, trihydrochloride 10.4 g (50 mmol) of α-oxo-4-ethoxyphenylacetic acid (Bandyopahyay et al., J. Ind. Chem. Soc. 66 (4), 239, 1989) are dissolved in 55 ml of methanol and reacted with 2.58 g (25 mmol) of diethylenetriamine. After six hours at 60 ° C., the mixture is allowed to cool to room temperature and 0.76 g (20 mmol) of sodium borohydride are added. The mixture is stirred overnight and then the reaction mixture is carefully mixed with dilute hydrochloric acid until no more gas is added

watch is. The reaction mixture is evaporated and dried at 100 ° C. in an oil pump vacuum for several hours. The backlog is in

Isopropanol added. Hydrogen chloride gas is bubbled in, stirred for two hours at room temperature and then for eight hours at 85 ° C. It is then evaporated, the residue is partitioned between ethyl acetate and sodium bicarbonate solution, the organic phase is sodium dried sulfate, filtered and evaporated. In the solution of the residue in tert. Butyl methyl ether is passed in to hydrogen chloride gas until saturation and the precipitate which has precipitated is filtered off with suction.

Yield: 13.7 g (80.4% of theory) of a pale yellow solid.

Analysis (based on solvent-free substance):

calc .: C 56.43 H 7.70 Cl 15.62 N 6.17 0 14.09

found: C 56.51 H 7.61 Cl 15.29 N 6.30

b) 3,6,9-Triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -2,10-bis- (4-ethoxybenzyl) -undecanedioic acid di-isopropyl ester

13.3 g (19.5 mmol) of diester from Example a) are tert with 12.57 g (64.4 mmol) of bromoacetic acid. butyl ester implemented in an analogous manner to Example 3d). After chromatographic purification, the title compound is obtained as a colorless oil.

Yield: 14.6 g (81.9% of theory)

Analysis (based on solvent-free substance):

calc .: C 65.69 H 8.71 N 4.60 021.00

Found: C 65.53 H 8.84 N 4.50

c) Gadolinium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -undecanedioic acid

14.2 g (15.5 mmol) of the compound prepared according to Example b) are dissolved in 45 ml of tetrahydrofuran and mixed with 55 ml of two normal sodium hydroxide solution, stirred for three hours at 55 ° C., adjusted to pH 1 with concentrated hydrochloric acid, concentrated on Rotary evaporator strong and cleans the residue

Ion exchange chromatography (cation exchanger (H ⁺ form), eluent: aqueous ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free complexing agent is obtained.

The penta acid is taken up in 120 ml of water and mixed with 2.81 g (7.77 mmol) of gadolinium oxide. The suspension is stirred at 90 ° C for 7 hours and filtered. The pH is then adjusted to 7.1 using a normal sodium hydroxide solution. The solution is then stirred at 70 ° C. for one hour after the addition of 1.4 g of activated carbon and filtered. The filtrate is lyophilized.

Yield: 12.4 g (93% of theory) of a colorless solid. Analysis (based on anhydrous substance):

calc .: C 44.70 H 4.45 N 4.89 022.33 Gd 18.29 Na 5.35

Found: C 44.56 H 4.52 N 4.81 Gd 18.14 Na 5.09

Example 6

Hafnium complex of the disodium salt of 3,6,9-triaza-3,9-bis (carboxymethyl) -6- {2- [4- (carboxymethoxy) phenyl] -1-carboxyethyl} -4- [4-propoxybenzyl] - undecanedioic acid a) N-benzyloxycarbonyl-3- [4-propoxyphenyl] alanine methyl ester

4.94 g (15 mmol) of N-benzyloxycarbonyl-tyrosine methyl ester are dissolved in 25 ml of anhydrous N, N-dimethylformamide and at 5 ° C under argon with 0.61 g (15.5 mmol) of sodium hydride dispersion (60% in mineral oil ) offset. The mixture is allowed to stir for 10 minutes, then 1.91 g (15.5 mmol) of propyl bromide are added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further two

Hours. For working up, the mixture is taken up in ethyl acetate and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The residue is used for purification on silica gel

Chromatographed hexane / diethyl ether / triethylamine.

Yield: 4.3 g (74.7% of theory) of colorless oil. Analysis (based on solvent-free substance):

calc .: C 67.91 H 6.78 N 3.77 021.54

Found: C 67.78 H 6.64 N 3.83

b) N-Benzyloxycarbonyl-2-amino-2- [4-propoxybenzyl] ethanol

4.15 g (11.2 mmol) of N-benzyloxycarbonyl-3- [4-propoxyphenyl] alanine methyl ester are dissolved in 20 ml of tert-butyl methyl ether and mixed with 0.17 g (4.5 mmol)

Sodium borohydride added. At 0 ° C 6 ml of methanol are added and the mixture is stirred for three hours under argon at a temperature below 5 ° C. Then 0.8 ml of acetic acid dissolved in 3 ml of tetrahydrofuran is added, 3 ml of water are added and the mixture is stirred for ten minutes at room temperature. The organic phase is separated off, washed with water and dried over sodium sulfate. The drying agent is filtered off with suction, the filtrate is evaporated and the residue is purified by chromatography on silica gel (eluent: ethyl acetate / hexane).

Yield: 3.55 g (92.3% of theory)

Analysis (based on solvent-free substance):

calc .: C 69.95 H 7.34 N 4.08 0 18.64

Found: C 69.74 H 7.42 N 3.96

c) 2-Amino-2- [4-propoxybenzyl] ethanol

3.4 g (10 mmol) of the Z-protected amine from Example b) are hydrogenated in analogy to Example 3c) with palladium catalysis.

Yield: 2.0 g (96.5% of theory) colorless oil. Analysis (based on solvent-free substance):

calc .: C 68.87 H 9.15 N 6.69 0 15.29

Found: C 69.02 H 9.08 N 6.47

d) N- [1- (4-Propoxybenzyl) -2-hydroxyethyl] iminodioic acid di-tert. -butyl ester

1.9 g (9.1 mmol) of the amine from Example c) are tert with 3.9 g (20 mmol) of bromoacetic acid. butyl ester implemented in an analogous manner to Example 3d). After chromatographic purification on silica gel, the dialkylation product is obtained as a colorless oil.

Yield: 3.6 g (90.4% of theory)

Analysis (based on solvent-free substance):

calc .: C 65.88 H 8.98 N 3.20 021.94

Found: C 65.97 H 9.06 N 3.14

e) N- [2-bromo-1- (4-propoxybenzyl) ethyl] iminodiacetic acid di-tert. -butyl ester

From 3.4 g (7.77 mmol) of the diester from Example d) and triphenylphosphine and N-bromosuccinimide, the bromide is obtained as a yellow oil in an analogous manner to Example 3e).

Yield: 3.25 g (83.6% of theory)

Analysis (based on solvent-free substance):

calc .: C 56.60 H 7.65 Br 15.97 N 2.80 O 15.98

Found: C 56.51 H 7.47 Br 16.04 N 2.64

f) N-Benzyloxycarbonyl-3- [4- (tert-butoxycarbonylmethoxy) phenyl] alanine tert-butyl ester 5.57 g (15 mmol) N-benzyloxycarbonyl-tyrosine tert. -butyl esters are reacted in analogy to example 1a) with tert-butyl bromoacetate to give the alkylated phenol.

Yield: 6.1 g (83.7% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 66.79 H 7.26 N 2.88 023.06

found: C 66.62 H 7.17 N 2.81

g) N- [N ', N'-bis (tert-butoxycarbonylmethyl) -2-aminoethyl] -N-benzyloxycarbonyl-3- [4- (tert-butoxycarbonylmethoxy) phenyl] alanine tert. -butyl ester

5.9 g (12.1 mmol) of the amine from Example f) in 20 ml of N, N-dimethylformamide are added at 0 ° C with 0.56 g (14.0 mmol) of sodium hydride. After 15 minutes, 4.69 g (13.3 mmol) of N, N-bis - [(tert-butoxycarbonyl) methyl] -2-bromoethylamine (M. Williams and H. Rapoport, J. Org. Chem 58, 1151 (1993)) and the mixture is left overnight at room temperature

keep stirring. The organic phase is then shaken out with tert-butyl methyl ether / sodium hydrogen carbonate solution, the tert-butyl methyl ether phase is dried over sodium sulfate and filtered. Then the organic phase is evaporated in vacuo and the residue is chromatographed on silica gel with hexane / ethyl acetate / triethylamine. The product-containing fractions are evaporated in vacuo.

Yield: 6.9 g (75.3% of theory) of a yellowish oil.

Analysis (based on solvent-free substance):

calc .: C 65.06 H 7.99 N 3.70 023.25

found: C 65.20 H 8.14 N 3.53

h) N- [N ', N'-bis (tert-butoxycarbonylmethyl) -2-aminoethyl] -3- [4- (tert-butoxycarbonylmethoxy) phenyl] alanine tert. -butyl ester 6.75 g (8.9 mmol) of the benzyloxycarbonyl-protected amine (example g) are hydrogenated with the addition of 0.7 g palladium (10%) on activated carbon at normal pressure and room temperature. When the uptake of hydrogen has ended, the catalyst is filtered off and the filtrate is evaporated to dryness.

Yield: 5.5 g (99.2% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 63.64 H 8.74 N 4.50 023.12

Found: C 63.49 H 8.87 N 4.63

i) 3,6,9-triaza-3,9-bis (tert-butoxycarbonylmethyl) -6- {2- [4- (tert-butoxycarbonylmethoxy) phenyl] -1- (tert-butoxycarbonyl) - ethyl} -4- [4-propoxybenzyl] -undecanedioic acid di-tert. -butyl ester

5.2 g (8.3 mmol) of the amine prepared according to Example h) and 4.36 g (8.7 mmol) of the bromide obtained according to Example e) are dissolved in 35 ml acetonitrile and treated with 15 ml 2N phosphate buffer solution (pH 8.0). The mixture is stirred vigorously at room temperature for 36 hours, the aqueous phosphate buffer phase being replaced with fresh buffer solution after 2, 8 and 24 hours. Then the organic phase is evaporated in vacuo and the

Chromatograph the residue on silica gel with hexane / diethyl ether / triethylamine. The product-containing fractions are evaporated in vacuo.

Yield: 7.6 g (87.8% of theory) of a yellowish oil.

Analysis (based on solvent-free substance):

calc .: C 65.68 H 8.80 N 4.03 021.49

Found: C 65.54 H 8.91 N 3.89

j) 3,6,9-Triaza-3,9-bis (carboxymethyl) -6- {2-I4- (carboxymethoxy) phenyl] -1-carboxyethyl} -4- [4-propoxybenzyl] undecanedioic acid 7.3 g (7 mmol) of the hexaester from Example i) are dissolved in 35 ml of methanol and stirred with 20 ml of two normal sodium hydroxide solution at 70 ° C. for five hours.

The methanol is then distilled off, taken up in water and concentrated with. Hydrochloric acid precipitated. The solid is filtered off with suction, washed neutral with water and the ligand is dried at 50 ° C. in vacuo.

Yield: 4.36 g (88.3% of theory) of a colorless solid.

Analysis (based on solvent-free substance):

calc .: C 56.17 H 6.14 N 5.95 031.74

found: C 56.03 H 6.01 N 6.13

k) Hafnium complex of the disodium salt of 3,6,9-triaza-3,9-bis (carboxymethyl) -6- {2- [4- (carboxymethoxy) phenyl] -1-carboxyethyl} -4- [4-propoxybenzyl ] undecanedioic acid

4.2 g (6 mmol) of hexa acid from Example j) are suspended in 120 ml of water and mixed with 1.47 g (6 mmol) of hafnium hydroxide (DJ. Williams et al., J. Chem. Soc. Dalton Trans. 2475, 1992) ) offset. The reaction solution is stirred at 100 ° C. for 36 hours. After complexation is complete, the mixture is filtered, concentrated to about half the previous volume and freeze-dried.

Yield: 5.1 g (92% of theory) of colorless lyophilisate. Analysis (based on anhydrous substance):

calc .: C 42.89 H 4.04 N 4.55 024.24 Hf 19.31 Na 4.98

Found: C 42.76 H 4.20 N 4.41 Hf 19.13 Na 4.72 Example 7

Terbium complex of the disodium salt of 3,6,9-triaza-6- (carboxymethyl) -3,9-bis- [2- (4-methoxyphenyl) -1-carboxyethyl] -2,10-bis- (4-methoxybenzyl) - undecanedioic acid a) 3- {4-methoxyphenyl] alanine tert. -butyl ester

7.12 g (30 mmol) tyrosine tert. butyl esters are dissolved in 28 ml of anhydrous N, N-dimethylformamide and at 5 ° C. under argon with 1.21 g (31 mmol)

Sodium hydride dispersion (60% in mineral oil) added. The mixture is allowed to stir for 15 minutes, then 4.4 g (31 mmol) of methyl iodide are added and the

Reaction temperature rise to room temperature and stir for another hour. For working up, the mixture is taken up in ethyl acetate and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The residue is used for purification on silica gel

Chromatographed hexane / diethyl ether / triethylamine.

Yield: 6.8 g (90.2% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 66.91 H 8.42 N 5.57 0 19.10

Found: C 66.98 H 8.55 N 5.33

b) 3- [4-methoxyphenyl] -2-bromo-propionic acid tert. -butyl ester 6.55 g (26.1 mmol) of the amino acid ester from Example a) are analogous to

Method by A. Quellenstein, et al. (THL 34, p. 1457, 1993) converted into the corresponding bromide. After chromatographic purification on silica gel, the product is obtained as a pale yellow solid.

Yield: 6.4 g (77.8% of theory) Analysis (based on solvent-free substance):

calc .: C 53.35 H 6.08 Br 25.35 0 15.23

Found: C 53.24 H 5.97 Br 25.21

c) N- (2-Hydroxyethyl) -2,4-bis- (4-methoxybenzyl) -3-azaglutaric acid di-tert-butyl ester

6.2 g (20 mmol) of the bromide from example b) are dissolved in 15 ml of N, N-dimethylformamide at 0 ° C., and 2.2 g (22 mmol) of potassium hydrogen carbonate are added. Then 0.54 g (8.9 mmol) of ethanolamine are added, the mixture is stirred at low temperature for 30 minutes and then at room temperature for three days. The batch is mixed with 100 ml of tert-butyl methyl ether, extracted with saturated sodium bicarbonate solution and saturated sodium chloride solution, and the organic phase is dried over sodium sulfate. After filtering, evaporate to dryness.

Yield: 5.8 g (49% of theory) of a colorless oil which slowly crystallizes through.

Analysis (based on solvent-free substance):

calc .: C 68.03 H 8.18 N 2.64 021.14

Found: C 67.76 H 8.23 N 2.88

d) N- (2-bromoethyl) -2,4-bis- (4-methoxybenzyl) -3-azaglutaric acid di-tert. -butyl ester

The bromide is obtained as a pale yellow oil from 5.6 g (10.6 mmol) of the diester from Example c) and triphenylphosphine and N-bromosuccinimide in an analogous manner to Example 3e).

Yield: 5.12 g (81.5% of theory) Analysis (based on solvent-free substance):

calc .: C 60.81 H 7.14 Br 13.48 N 2.36 0 16.20

Found: C 60.70 H 7.08 Br 13.29 N 2.44

e) 3,6,9-triaza-6- (tert-butoxycarbonylmethyl) -3,9-bis- [2- (4-methoxyphenyl) -1- (tert-butoxycarbonyl) ethyl] -2,10- bis- (4-methoxybenzyl) -undecanedioic acid di-tert-butyl ester

4.85 g (8.2 mmol) of the bromide prepared according to Example d) and 0.67 g (4 mmol) of glycine tert-butyl ester hydrochloride are placed in 35 ml of acetonitrile and mixed with 20 ml of 2N phosphate buffer solution (pH 8 , 0) offset. The mixture is stirred vigorously at room temperature for 30 hours, the aqueous phosphate buffer phase being replaced with fresh buffer solution after 2 and 18 hours. Then the organic phase is evaporated in vacuo and the residue is chromatographed on silica gel with hexane / diethyl ether / triethylamine. The product-containing fractions are evaporated in vacuo.

Yield: 4.1 g (88.8% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 68.66 H 8.29 N 3.64 0 19.40

Found: C 68.73 H 8.31 N 3.50

f) Terbium complex of the disodium salt of 3,6,9-triaza-6- (carboxymethyl) -3,9-bis- [2- (4-methoxyphenyl) -1-carboxyethyl] -2,10-bis- (4-methoxybenzyl ) -undecanedioic acid

3.9 g (3.4 mmol) of the pentaester prepared according to Example e) are dissolved in 15 ml of tetrahydrofuran and mixed with 15 ml of two normal sodium hydroxide solution, stirred for three hours at 55 ° C, adjusted to pH 1 with concentrated hydrochloric acid, concentrated on Rotary evaporator strong and cleans the residue

The penta acid is taken up in 100 ml of water and 0.85 g (1.7 mmol)

Terbium carbonate hydrate added. The suspension is stirred at 70 ° C. for 15 hours and filtered. The pH is then adjusted to 7.1 using a normal sodium hydroxide solution.

The solution is then a at 90 ° C after adding 0.4 g of activated carbon

Stirred for an hour and filtered. After freeze drying, the filtrate gives a colorless solid.

Yield 3.4 g (93.1% of theory)

Analysis (based on anhydrous substance):

calc .: C 51.45 H 4.69 N 3.91 020.86 Tb 14.80 Na 4.28

Found: C 51.27 H 4.73 N 3.76 Tb 14.68 Na 3.94

Example 8

Holmium complex of the disodium salt of 3,6,9-triaza-6,9-bis (carboxymethyl) -3- [(4-methoxybenzyl) carboxymethyl] -10- (4-ethoxybenzyl) -2- (4-methoxybenzyl) - undecanedioic acid a) N-benzyl-N- (2-hydroxyethyl) glycine tert. -butyl ester

15.1 g (100 mmol) of N-benzylethanolamine are dissolved in 50 ml of tetrahydrofuran, and 15 ml of water and 13.8 g (100 mmol) of potassium carbonate are added. To

20.5 g (105 mmol) of tert-butyl bromoacetate are added dropwise and the mixture is stirred at 65 ° C. for 6 hours. After cooling, the mixture is filtered, concentrated in vacuo and the residue is chromatographed on silica gel with diethyl ether / hexane / triethylamine. The product fractions are evaporated in a vacuum and dried.

Yield: 24.8 g (93.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 67.90 H 8.74 N 5.28 O 18.09

Found: C 67.87 H 8.88 N 5.19

b) N-Benzyl-N- (2-bromethyl) glycine tert-butyl ester

A solution of 20 g (75.4 mmol) of the compound described under a) and 22.9 g (87.1 mmol) of triphenylphosphine in 400 ml of dichloromethane is added in portions at 0 ° C with 15.5 g (87.1 mmol) N-bromosuccinimide added and

Yield: 20.3 g (81.7% of theory) of colorless oil. Analysis (based on solvent-free substance):

calc .: C 54.89 H 6.76 Br 24.34 N 4.27 0 9.75

Found: C 54.77 H 6.81 Br 24.12 N 4.34

c) 2,4-bis (4-hydroxybenzyl) -3-azaglutaric acid di-isopropyl ester

9.01 g (50.0 mmol) of 4-hydroxyphenylpyruvic acid and 9.06 g (50.0 mmol) of tyrosine are dissolved in 60 ml of methanol and stirred at 60 ° C. for six hours. Then allowed to cool to room temperature and add 0.76 g (20 mmol) of sodium borohydride. The mixture is allowed to stir overnight and then dilute hydrochloric acid is added to the reaction mixture carefully, to none

Gas evolution can be observed more. The reaction mixture is evaporated and dried in an oil pump vacuum at 100 ° C for several hours. The residue is taken up in isopropanol. One passes hydrogen chloride gas to

Saturation, stirring for two hours at room temperature and then eight hours at 85 ° C. It is then evaporated, the residue is partitioned between ethyl acetate and sodium bicarbonate solution, the organic phase is dried over sodium sulfate, filtered and evaporated. The backlog

chromatographed on silica gel using hexane / ethyl acetate as

Eluent. The fractions containing the pure product are combined and evaporated.

Yield: 16.0 g (74.5% of theory) of a pale yellow oil.

Analysis (based on solvent-free substance):

calc .: C 67.11 H 7.28 N 3.26 O 22.35

Found: C 67.04 H 7.33 N 3.16 d) N- (3-Aza-3-benzyl-4-tert-butoxycarbonyl-butyl) -2,4-bis (4-hydroxybenzyl) -3-azaglutaric acid di-isopropyl ester

10.8 g (33.0 mmol) of the compound prepared according to Example b) and 12.9 g (30 mmol) of the compound described in Example c) are placed in 45 ml of acetonitrile and mixed with 25 ml of 2N phosphate buffer solution (pH 8, 0) offset. The mixture is stirred vigorously at room temperature for 22 hours, the aqueous

Phosphate buffer phase is exchanged for fresh buffer solution after 2 and 7 hours. Then the organic phase is evaporated in vacuo and the residue is chromatographed on silica gel with hexane / ethyl acetate / triethylamine. The product-containing fractions are in a vacuum

evaporated.

Yield: 13.9 g (68.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 69.21 H 7.74 N 4.14 0 18.91

Found: C 69.13 H 7.78 N 4.16

e) N- (3-Aza-3-benzyl-4-tert-butoxycarbonyl-butyl) -2,4-bis (4-methoxybenzyl) -3-azaglutaric acid di-isopropyl ester

12.5 g (18.5 mmol) of the compound described in Example d) are dissolved in 50 ml of anhydrous N, N-dimethylformamide and at 0 ° C. under argon with 1.60 g (40.0 mmol) of sodium hydride dispersion (60% in mineral oil ) offset. The mixture is allowed to stir for 15 minutes, then 6.81 g (48.0 mmol) of methyl iodide is added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further four hours. For working up, the mixture is taken up in toluene and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is on silica gel with hexane / diethyl ether / triethylamine

chromatographed, the product-containing fractions are combined and

evaporated. Yield: 11.6 g (89.2% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 69.86 H 8.01 N 3.97 0 18.16

Found: C 69.78 H 8.23 N 3.78

f) N- (3-aza-4-tert-butoxycarbonyl-butyl) -2,4-bis- (4-methoxybenzyl) -3-azaglutaric acid di-isopropyl ester 11.0 g (15.5 mmol) of the Example e) compound prepared are dissolved in 50 ml of ethanol and after the addition of 1.0 g of palladium (10%) on activated carbon under a hydrogen atmosphere at room temperature until the end

Yield: 9.35 g (97.5% of theory)

Analysis (based on solvent-free substance):

calc .: C 66.43 H 8.20 N 4.56 020.82

Found: C 66.54 H 8.33 N 4.46

g) N- [3-aza-4-tert-butoxycarbonyl-3- (2-hydroxyethyl) butyl] -2,4-bis- (4-methoxybenzyl) -3-azaglutaric acid di-isopropyl ester 8.99 g (14.6 mmol) of the compound described in Example f) are dissolved in 30 ml of tetrahydrofuran and mixed with 2 ml of water and 2.02 g (14.6 mmol)

Potassium carbonate added. After 2.2 g (17.5 mmol) of bromoethanol have been added dropwise, the mixture is stirred at 65 ° C. for 6 hours. After cooling, it is filtered, in vacuo

concentrated and the residue chromatographed on silica gel with diethyl ether / hexane / triethylamine. The product fractions are evaporated in a vacuum and dried

Yield: 7.84 g (81.4% of theory) of colorless oil. Analysis (based on solvent-free substance):

calc .: C 65.63 H 8.26 N 4.25 021.86

found: C 65.78 H 8.40 N 4.11

h) N- [3-aza-4-tert-butoxycarbonyl-3- (2-bromomethyl) butyl] -2,4-bis (4-methoxybenzyl) -3-azaglutaric acid di-isopropyl ester A solution of 7 , 73 g (11.7 mmol) of those described in Example g)

2.30 g (12.9 mmol) of N-bromosuccinimide are added in portions at 0 ° C. to the compound and 3.39 g (12.9 mmol) of triphenylphosphine in 50 ml of dichloromethane and the mixture is then stirred at room temperature for 20 hours. The solution is evaporated and the residue is extracted with hexane. It arises

Precipitate, which is separated off and washed with hexane. The combined filtrates are evaporated and the residue on silica gel

Chromatographed hexane / diethyl ether. Evaporation of the product fractions gives a colorless oil.

Yield: 7.07 g (83.5% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 59.91 H 7.40 Br 11.07 N 3.88 0 17.74

found: C 60.04 H 7.52 Br 10.89 N 3.95

i) N-benzyl-tyrosine tert. -butyl ester

16.9 g (71.5 mmol) tyrosine tert. -butyl ester and 8.33 g (78.6 mmol) of benzaldehyde are stirred in 50 ml of methanol for 3 hours at 24 ° C. and then 3.37 g (53.6 mmol) of sodium cyanoborohydride are added. After stirring for 24 hours

At room temperature, the batch is adjusted to pH 2 by carefully adding half-concentrated hydrochloric acid, then neutralized with concentrated aqueous sodium bicarbonate solution and after extensive evaporation of Methanol shaken out with ethyl acetate. The organic phase is dried over anhydrous magnesium sulfate, filtered and evaporated. The residue is on silica gel with diethyl ether / hexane / triethylamine

chromatographed; the product-containing fractions are combined and evaporated.

Yield: 15.7 g (67% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 73.37 H 7.70 N 4.28 0 14.66

Found: C 73.25 H 7.84 N 4.16

j) N-Benzyl-2- (4-hydroxybenzyl) -3-azaglutaric acid di-tert-butyl ester

15.1 g (46.1 mmol) N-benzyl-tyrosine tert. butyl ester (Example i) are dissolved in 50 ml of tetrahydrofuran and mixed with 5 ml of water and 9.54 g (69 mmol)

Potassium carbonate added. After the dropwise addition of 9.89 g (51 mmol) of bromoacetic acid tert. -butyl ester is stirred at 65 ° C for two days. After cooling, the mixture is filtered, concentrated in vacuo and the residue on silica gel

Chromatographed diethyl ether / hexane / triethylamine. The product fractions are evaporated in a vacuum and dried.

Yield: 14.9 g (73.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 74.33 H 8.22 N 3.94 0 13.50

Found: C 74.27 H 8.26 N 3.74

k) N-benzyl-2- (4-ethoxybenzyl) -3-azaglutaric acid di-tert. -butyl ester 13.2 g (30 mmol) of N-benzyl-2- (4-hydroxybenzyl) -3-azaglutaric acid di-tert-butyl ester (Example j) are dissolved in 50 ml of anhydrous N, N-dimethylformamide and at 0 ° C under argon with 1.31 g (33 mmol) sodium hydride dispersion (60% in Mineral oil). The mixture is allowed to stir for 15 minutes, 8.05 g (51.7 mmol) of ethyl iodide are then added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further three hours. For working up, the mixture is taken up in toluene and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is chromatographed for purification on silica gel with hexane / diethyl ether / triethylamine. The product fractions are evaporated in a vacuum and dried.

Yield: 12.7 g (90.3% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 71.61 H 8.37 N 2.98 0 17.03

Found: C 71.72 H 8.43 N 2.87

l) 2- (4-ethoxybenzyl) -3-azaglutaric acid di-tert-butyl ester

14.2 g (30.2 mmol) of the compound prepared according to Example k) are dissolved in 75 ml of ethanol and after the addition of 1.4 g of palladium (10%) on activated carbon under a hydrogen atmosphere at room temperature until the end

Yield: 11.3 g (98.6% of theory)

Analysis (based on solvent-free substance):

calc .: C 66.46 H 8.77 N 3.69 021.08

Found: C 66.44 H 8.63 N 3.57 m) 3,6,9-triaza-3,6-bis (tert-butoxycarbonylmethyl) -2- (4-ethόxybenzyl) -9,9-bis- [2- (4-methoxyphenyl) -1 - (( 1-methylethoxy) carbonyl) ethyl] nonanoic acid tert. - butyl ester

6.85 g (9.49 mmol) of the compound prepared according to Example h) and 3.60 g (9.49 mmol) of the compound described in Example I) are in 15 ml

Acetonitrile submitted and mixed with 7.5 ml of 2N phosphate buffer solution (pH 8.0). The mixture is stirred vigorously at room temperature for 22 hours, the aqueous phosphate buffer phase being replaced with fresh buffer solution after 2 and 7 hours. Then the organic phase is evaporated in vacuo and the residue is chromatographed on silica gel with hexane / ethyl acetate / triethylamine. The product-containing fractions are in a vacuum

evaporated.

Yield: 6.26 g (64.6% of theory) of colorless oil. Analysis (based on solvent-free substance):

calc .: C 67.10 H 8.40 N 4.12 020.38

found: C 67.21 H 8.54 N 4.17

n) Holmium complex of the disodium salt of 3,6,9-triaza-6,9-bis (carboxymethyl) -3 - [(4-methoxybenzyl) carboxymethyl] -10- (4-ethoxybenzyl) -2- (4-methoxybenzyl ) -undecanedioic acid

6.11 g (5.99 mmol) of the compound prepared according to Example m) are dissolved in 20 ml of tetrahydrofuran and mixed with 24 ml of two normal sodium hydroxide solution, the mixture is stirred at 60 ° C. for two hours, adjusted to pH 1 with concentrated hydrochloric acid, and concentrated on Rotary evaporator strong and cleans the residue

Ion exchange chromatography (cation exchanger (H ⁺ form), Eiuens:

aqueous ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free complexing agent is obtained.

The penta acid is taken up in 250 ml of water and 1.13 g (2.99 mmol) of holmium oxide are added. The suspension is stirred at 100 ° C. for 16 hours and filtered. Then pH 7.3 is adjusted with a normal sodium hydroxide solution. The solution is then stirred at 80 ° C for one hour after the addition of 0.6 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid. Yield 5.55 g (95.3% of theory)

Analysis (based on anhydrous substance):

calc .: C 48.11 H 4.56 N 4.32 021.36 Ho 16.94 Na 4.72

Found: C 48.12 H 4.64 N 4.21 Ho 16.76 Na 4.55

Example 9

Erbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -4,8-bis- (4-propoxybenzyl) -undecanedioic acid a ) Propyl α-oxo-4-ethoxyphenylacetate 10.4 g (50 mmol) α-oxo-4-ethoxyphenylacetic acid (Bandyopahyay et al., J. Ind. Chem. Soc. 66 (4), 239, 1989) and 1 0 g of p-toluenesulfonic acid monohydrate are refluxed in a mixture of 100 ml of toluene and 50 ml of n-propanol on a water separator until no more water separates out. The mixture is then evaporated in vacuo, the residue is partitioned between ethyl acetate and sodium hydrogen carbonate solution, the organic phase is dried over magnesium sulfate, filtered and evaporated.

Yield: 10.9 g (87.3% of theory) of a yellowish oil.

Analysis (based on solvent-free substance):

calc .: C 67.18 H 7.25 025.57

Found: C 67.33 H 7.32 b) 3-Aza-2- (4-ethoxybenzyl) -5-hydroxy-4- (4-propoxybenzyl) valeric acid propyl ester

10.1 g (40.4 mmol) of the compounds described in Example a) and 8.44 g (40.4 mmol) of the compounds described in Example 4c) are stirred in 80 ml of methanol at 50 ° C. for two hours. Then 0.76 g (20.2 mmol) of sodium borohydride are added in portions at 0 ° C. The mixture is left to stir overnight and then dilute hydrochloric acid is carefully added to the reaction mixture until no further gas evolution can be observed. The reaction mixture is evaporated and the residue is partitioned between ethyl acetate and sodium hydrogen carbonate solution, the organic phase is dried over sodium sulfate, filtered and evaporated. The residue is chromatographed on silica gel using hexane / ethyl acetate as the eluent. The fractions containing the pure product are combined and evaporated.

Yield: 14.1 g (78.7% of theory) of a pale yellow oil.

Analysis (based on solvent-free substance):

calc .: C 70.40 H 8.41 N 3.16 0 18.03

Found: C 70.28 H 8.53 N 3.17

c) 3-Aza-2- (4-ethoxybenzyl) -5-hydroxy-4- (4-propoxybenzyl) -3- (tert-butoxycarbonylmethyl) -valeric acid propyl ester

13.6 g (30.7 mmol) of the compound described in Example b) are dissolved in 150 ml of toluene. 4.24 g (30.7 mmol) of powdered potassium carbonate and 6.58 g (33.7 mmol) of bromoacetic acid tert are added. -butyl ester and stirred until the reaction is complete at an internal temperature of 70 ° C. Then it is filtered, evaporated and the residue is chromatographed on silica gel with hexane / ethyl acetate. The fractions containing the pure product are combined and evaporated in vacuo.

Yield: 12.4 g (72.6% of theory) of a yellowish oil. Analysis:

calc .: C 68.91 H 8.49 N 2.51 020.08

Found: C 70.06 H 8.55 N 2.24

d) 3-Aza-5-bromo-2- (4-ethoxybenzyI) -4- (4-propoxybenzyI) -3- (tert-butoxycarbonylmethyl) -valeric acid propyl ester

A solution of 12.0 g (21.5 mmol) of the compound described under c) and 6.21 g (23.7 mmol) of triphenylphosphine in 70 ml of dichloromethane is added in portions at 0 ° C with 4.21 g (23.7 mmol) N-bromosuccinimide added and

then stirred for 20 hours at room temperature. The solution is evaporated and the residue is extracted with hexane. It arises

Yield: 10.9 g (81.4% of theory) of colorless oil. Analysis (based on solvent-free substance):

calc .: C 61.93 H 7.47 Br 12.88 N 2.26 0 15.47

Found: C 62.14 H 7.31 Br 12.69 N 2.42

e) 3,6,9-Triaza-3,6,9-tris (tert-butoxycarbonylmethyl) -2,10-bis- (4-ethoxybenzyl) -4,8-bis- (4-propoxybenzyl) -undecanedioic acid -di-propyl ester

10.5 g (16.9 mmol) of the compound prepared according to Example d) and 1.11 g (8.46 mmol) of glycine tert. Butyl ester are placed in 30 ml of acetonitrile and mixed with 15 ml of 2N phosphate buffer solution (pH 8.0). The approach is at

Room temperature stirred vigorously for 22 hours, the aqueous

Phosphate buffer phase is exchanged for fresh buffer solution after 2 and 7 hours. Then the organic phase is evaporated in vacuo and the residue was chromatographed on silica gel with hexane / ethyl acetate / triethylamine. The product-containing fractions are in a vacuum

evaporated.

Yield: 6.83 g (66.7% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 69.45 H 8.58 N 3.47 0 18.50

Found: C 69.27 H 8.50 N 3.59

f) Erbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) -2,10-bis- (4-ethoxybenzyl) -4,8-bis- (4-propoxybenzyl) - undecanedioic acid

6.64 g (5.48 mmol) of the compound prepared according to Example e) are dissolved in 20 ml of tetrahydrofuran and mixed with 24 ml of two normal sodium hydroxide solution, the mixture is stirred for two hours at 60 ° C., adjusted to pH 1 with concentrated hydrochloric acid, and concentrated on Rotate evaporator and clean the residue by ion exchange chromatography (cation exchanger (H ⁺ form), eluent: aqueous ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free complexing agent is obtained.

The penta acid is taken up in 250 ml of water and 1.04 g (2.74 mmol) of erbium oxide are added. The suspension is stirred at 100 ° C. for 16 hours and filtered. Then pH 7.3 is adjusted with a normal sodium hydroxide solution. The solution is then stirred at 80 ° C. for one hour after the addition of 0.6 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid. Yield 5.78 g (90.3% of theory)

Analysis (based on anhydrous substance):

calc .: C 53.55 H 5.36 N 3.60 0 19.20 Er 14.34 Na 3.94

Found: C 53.63 H 5.42 N 3.51 Er 14.21 Na 3.77 Example 10

Examination of acute toxicity (LD ₅₀ ) after single intravenous administration to the mouse

The mice sitting in a single compulsory cage (strain: NMRI (SPF), breeder: Schering, average weight: 20 g, same gender distribution) were placed in one of the caudal veins with a contrast medium

Speed of 2 ml / min. and administered different doses. The number of animals that died by a specified time was determined (3 hours, 24 hours, 3 days and 7 days).

The LD ₅₀ for the ytterbium complex according to Example 4e is 15 mmol / kg

Body weight.

Example 11 Lutetium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -5- (4-ethoxybenzyl) -undecanedioic acid a) 3,6,9-triaza-3,6,9 -tris- (tert-butoxycarbonylmethyl) -5- (4-ethoxybenzyl) -undecanedioic acid di-tert-butyl ester

16.7 g (21.4 mmol) 3,6,9-triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -5- (4-hydroxybenzyl) -undecanedioic acid di-tert. -butyl ester (DOS 3710730) are dissolved in 50 ml of anhydrous N, N-dimethylformamide and 0.94 g (23.5 mmol) of sodium hydride dispersion (60% in mineral oil) are added at 0 ° C. under argon. The mixture is allowed to stir for 15 minutes, then 3.74 g (24.0 mmol) of ethyl iodide are added, the

The reaction temperature rises to room temperature and is stirred for a further four hours. For working up, the mixture is taken up in toluene and shaken out several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is on silica gel with hexane / diethyl ether / triethylamine chromatographed, the product-containing fractions are combined and evaporated.

Yield: 16.4 g (94.8% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 63.92 H 9.11 N 5.20 O 21.78

Found: C 63.77 H 9.28 N 5.13

b) Lutetium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -5- (4-ethoxybenzyl) -undecanedioic acid

16.1 g (20 mmol) of the compound prepared according to Example a) are dissolved in 50 ml of tetrahydrofuran and mixed with 60 ml of two normal sodium hydroxide solution, the mixture is stirred for two hours at 60 ° C., adjusted to pH 1 with concentrated hydrochloric acid, and concentrated on a rotary evaporator and purifies the residue by ion exchange chromatography (cation exchanger (H ⁺ form), eluent: aqueous ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free complexing agent is obtained.

The penta acid is taken up in 250 ml of water and mixed with 3.98 g (10 mmol) of lutetium oxide. The suspension is stirred at 100 ° C. for 36 hours and filtered. Then pH 7.3 is adjusted with a normal sodium hydroxide solution. The solution is then stirred at 80 ° C. for one hour after the addition of 1.6 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid. Yield: 14.1 g (94.8% of theory)

Analysis (based on anhydrous substance):

calc .: C 37.16 H 3.80 N 5.65 023.67 Lu 23.53 Na 6.18

Found: C 37.03 H 3.94 N 5.51 Lu 23.38 Na 5.90 Example 12

Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (2-ethoxybenzyl) -undecanedioic acid a) N-benzyloxycarbonyl-3- [2-hydroxyphenyl] alanine methyl ester

9.5 g (52.4 mmol) of o-tyrosine (2-hydroxyphenylalanine, Heraeus) are suspended in 48 ml of methanol, cooled in an ice bath, and 7.6 ml (105 mmol) of thionyl chloride are added dropwise. After one hour, the mixture is heated to reflux temperature and stirred for three hours. Then allowed to stir overnight at room temperature. The mixture is evaporated to dryness, the residue is taken up in methanol, the mixture is evaporated and the procedure is repeated twice. It is taken up in 50 ml of water, adjusted to pH 8.5 with 1.5 molar sodium carbonate solution and 22.1 ml (63 mmol) of benzyl chloroformate are added under pH control. The mixture is stirred for four hours at room temperature, the organic phase is separated off, washed with water and dried over sodium sulfate. After evaporation, the residue on silica gel (methylene chloride / ethyl acetate)

chromatographed.

Yield: 13.5 g (78.2% of theory) of a colorless oil which slowly crystallizes.

Analysis (based on solvent-free substance):

calc .: C 65.64 H 5.82 N 4.25 O 24.29

Found: C 65.57 H 5.68 N 4.30

b) N-Benzyloxycarbonyl-3- [2-ethoxyphenyl] alanine methyl ester

10.2 g (31 mmol) of the ortho-phenol from Example a) are dissolved in 6 ml of N, N-dimethylformamide at 40 ° C., 9.2 g (66.5 mmol) of potassium carbonate and 0.3 ml of water are added . 5.7 ml (43.4 mmol) of diethyl sulfate are then added dropwise and the mixture is stirred for 3.5 hours. 6.6 ml of ammonia are added and the mixture is left to stand for one hour. Then add a little water and extracted with tert-butyl methyl ether. The organic phase is separated off, washed with dilute sulfuric acid and water. You dry over

Sodium sulfate, evaporates after filtering off and chromatograph the residue on silica gel.

Yield: 8.2 g (74% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 67.21 H 6.49 N 3.92 022.38

Found: C 67.09 H 6.53 N 3.77

c) N-Benzyloxycarbonyl-2- [2-ethoxybenzyl] -2-aminoethanol

7.9 g (22 mmol) of N-benzyloxycarbonyl-3- [2-ethoxyphenyl] alanine methyl ester (Example b) are dissolved in 63 ml of tert-butyl methyl ether, and 1.1 g (30.1 mmol) of sodium borohydride are added . 15 ml of methanol are added at 5 ° C. and the mixture is stirred at constant temperature for five hours. Then 1.5 ml of acetic acid dissolved in 5 ml of tetrahydrofuran are added, 9 ml of water are added and the mixture is stirred for ten minutes at room temperature. The organic phase is separated off, washed with water and dried over sodium sulfate. The drying agent is suctioned off, the filtrate is evaporated and the residue is chromatographed on silica gel for purification.

Yield: 7.25 g (100% of theory) of a colorless oil which crystallizes rapidly. Analysis (based on solvent-free substance):

calc .: C 69.28 H 7.04 N 4.25 0 19.43

Found: C 69.32 H 7.00 N 4.18

d) N-Benzyloxycarbonyl-2- [2-ethoxybenzyl] -1,4,7-triazaheptane, dihydrochloride

7.2 g (22 mmol) of the alcohol from Example c) are dissolved in 18 ml of tetrahydrofuran and 4.9 ml (35 mmol) of triethylamine are added at room temperature. you added 2.54 ml (32.6 mmol) of methanesulfonoyl chloride dissolved in 2 ml of tetrahydrofuran and stirred at 20 ° C. for six hours. 22.2 ml (330 mmol) of ethylenediamine are then added dropwise at a temperature between 30 ° C. and 45 ° C. The mixture is heated to 50 ° C. and the batch is stirred for four hours. Then the reaction mixture is evaporated, the residue is taken up in ethyl acetate and washed with water. The organic phase is cooled in an ice bath and concentrated with. Hydrochloric acid added. The resulting precipitate is filtered off, washed with cold isopropanol and dried at 50 ° C.

Yield: 7.5 g (76.7% of theory) of a colorless solid.

Analysis (based on solvent-free substance):

calc .: C 56.76 H 7.03 Cl 15.95 N 9.45 0 10.80

Found: C 56.62 H 7.11 Cl 15.80 N 9.36

e) 2- [2-ethoxybenzyl] -1, 4,7-triazaheptane, dihydrochloride

7.2 g (16.2 mmol) of the Z-protected amine from Example d) are suspended in 72 ml of methanol, 1.08 g of palladium (10%) on activated carbon and 0.5 ml of water are added, and at normal pressure, at Room temperature hydrogenated. When the uptake of hydrogen has ended, the catalyst is filtered off and the filtrate is evaporated.

Yield: 4.9 g (97.5% of theory) of a colorless solid. Analysis (based on solvent-free substance):

calc .: C 50.33 H 8.12 Cl 22.85 N 13.54 0 5.16

Found: C 50.17 H 8.34 Cl 23.11 N 13.40 f) 3,6,9-Triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -4- (2-ethoxybenzyl) -undecanedioic acid di-tert. -butyl ester

11.2 g (81.5 mmol) of potassium carbonate are dissolved in 11 ml of water and 4.8 g (15.5 mmol) of triamine (Example e) are added at 35 ° C. 12.5 ml (85.3 mmol) of bromoacetic acid tert are added. -butyl ester is added dropwise and the mixture is stirred at 65 ° C. for seven hours. After stirring for 18 hours at room temperature, water is added to the reaction mixture and the mixture is extracted with ethyl acetate. The organic phase is dried over sodium sulfate, evaporated and the residue is chromatographed on silica gel (methylene chloride / methanol). After evaporation of the product-containing fractions, the pentaester is obtained as a pale yellow oil.

Yield: 11.9 g (95% of theory)

Analysis (based on solvent-free substance):

calc .: C 63.92 H 9.11 N 5.20 021.78

Found: C 64.05 H 9.23 N 5.07

g) 3,6,9-Triaza-3,6,9-tris (carboxymethyl) -4- (2-ethoxybenzyl) -undecanedioic acid

11.75 g (14.5 mmol) of pentaester from example f) are dissolved in 86 ml of methanol and reacted with 4.65 g (116.3 mmol) of sodium hydroxide in 7.1 ml of water. The mixture is stirred at 65 ° C. for four hours, then the methanol is evaporated off, water is added and the mixture is evaporated again. It is taken up in water and adjusted to pH 1.8 with an acidic ion exchanger. After filtering off the exchanger, the aqueous solution is largely concentrated and the pentic acid is purified by preparative HPLC (water / methanol / pH 2.5). The product-containing fractions are evaporated, taken up again in water and freeze-dried. Yield: 4.9 g (64% of theory) Analysis (based on solvent-free substance):

calc .: C 52.37 H 6.31 N 7.97 0 33.36

Found: C 52.19 H 6.46 N 7.88

h) Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (2-ethoxybenzyl) -undecanedioic acid

3.72 g (7.05 mmol) of pentic acid from Example g) are dissolved in 19 ml of water at 60 ° C., and 1.85 g (3.53 mmol) of ytterbium carbonate are added in portions. After complexation is complete, the mixture is filtered, adjusted to pH 7.0, stirred with 0.2 g of activated carbon at 100 ° C. for ten minutes, filtered again and the filtrate is lyophilized.

Yield: 4.6 g (88% of theory) of colorless lyophilisate. Analysis (based on anhydrous substance):

calc .: C 37.26 H 3.81 N 5.67 023.74 Yb 23.34 Na 6.20

Found: C 37.13 H 4.02 N 5.55 Yb 23.18 Na 5.87

Example 13 a) Ytterbium complex of the dimeglumine salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid

2.9 g (5.5 mmol) of 3,6,9-triaza-3,6,94ris- (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid (EP 0405704, Example 8b) are suspended in 20 ml of water and complexed with 1.45 g (2.75 mmol) of ytterbium carbonate at 60 ° C. After the reaction has ended, the batch is neutralized with methylglucamine. The mixture is filtered and the metal complex is obtained by freeze-drying the filtrate.

Yield: 5.7 g (95.3% of theory) of colorless lyophilisate.

Analysis (based on anhydrous substance):

calc .: C 40.85 H 5.93 N 6.44 0 30.88 Yb 15.90

Found: C 40.67 H 6.08 N 6.17 Yb 15.62

b) Ytterbium complex of the di- (2-amino-1,3,4-butanetriol) salt of the 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) - undecanedioic acid

The title compound is obtained in a manner analogous to example a) if the complex acid is neutralized with 2-amino-1,3,4-butanetriol.

c) Cerium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid

The title compound is obtained in an analogous manner to Example a) if the ligand (EP 0405704, Example 8b) is reacted with cerium carbonate and with

Sodium hydroxide solution neutralized. d) Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid

2.1 g (4 mmol) of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid (EP 0405704, Example 8b) are suspended in 15 ml of water and complexed with 1.05 g (2 mmol) of ytterbium carbonate at 60 ° C. After finished

The complexation is neutralized with 1N sodium hydroxide solution. You filter the

Complex solution and wins the title compound by freeze drying the

Filtrate.

Yield: 3.0 g (100% of theory) of colorless lyophilisate.

Analysis (based on anhydrous substance):

calc .: C 37.26 H 3.81 N 5.67 023.74 Yb 23.34 Na 6.20

Found: C 37.14 H 4.11 N 5.50 Yb 23.22 Na 5.94

e) Lutetium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid

3.0 g (5.7 mmol) of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid (EP 0405704, Example 8b) are added in 15 ml Suspended water and complexed with 1.07 g (2.7 mmol) of lutetium oxide at 95 ° C. When the complexation is complete, the batch is neutralized with 1N sodium hydroxide solution. The solution is filtered and the title compound is obtained by freeze-drying the filtrate.

Yield: 3.9 g (92% of theory) of colorless lyophilisate.

Analysis (based on anhydrous substance):

calc .: C 37.16 H 3.80 N 5.65 023.67 Lu 23.53 Na 6.18

Found: C 37.02 H 4.01 N 5.53 Lu 23.36 Na 5.87

The corresponding bismuth complex (from

Bismuth oxycarbonate), the hafnium complex (from hafnium hydroxide), the Lead complex (from lead carbonate), the lanthanum complex (from lanthanum carbonate), the dysprosium complex (from dysprosium oxide), the erbium complex (from

Erbium carbonate), the terbium complex (made of terbium carbonate), the

Holmium complex (made of holmium carbonate) and the praseodymium complex (made of praseodymium carbonate).

Example 14

Gadoiinium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (2-butoxybenzyl) -undecanedioic acid a) N-benzyloxycarbonyl-3- [2-butoxyphenyl] alanine methyl ester

5.0 g (15.2 mmol) of the ortho-phenol from Example 2a) are dissolved in 4 ml of N, N-dimethylformamide at 40 ° C., with 4.5 g (31.1 mmol) of potassium carbonate and 0.2 ml Water added. Then 2.1 g (15.5 mmol) of n-butyl bromide are added dropwise and the mixture is stirred for 5 hours. 3.2 ml of ammonia are added and the mixture is left to stand for one hour. Then a little water is added and the mixture is extracted with tert-butyl methyl ether. The organic phase is separated off, washed with dilute sulfuric acid and water. You dry over

Yield: 4.7 g (80.2% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 68.55 H 7.06 N 3.63 020.75

found: C 68.42 H 7.18 N 3.59

b) N-Benzyloxycarbonyl-2- [2-butoxybenzyl] -2-aminoethanol

3.9 g (11 mmol) of N-benzyloxycarbonyl-3- [2-butoxyphenyl] alanine methyl ester (Example a) are dissolved in 30 ml of tert-butyl methyl ether and 0.55 g

(15 mmol) sodium borohydride added. At 3 ° C 8 ml of methanol are added and the mixture is stirred for five hours at constant temperature. Then 0.8 ml of acetic acid dissolved in 3 ml of tetrahydrofuran is added, 5 ml of water are added and the mixture is stirred at room temperature for ten minutes. The organic phase is separated off, washed with water and dried over sodium sulfate. The drying agent will suction filtered, the filtrate evaporated and the residue chromatographed on silica gel for purification.

Yield: 3.4 g (86.5% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 70.56 H 7.61 N 3.92 0 17.90

found: C 70.43 H 7.60 N 4.07 c) N-benzyloxycarbonyl-2- [2-butoxybenzyl] -1,4,7-triazaheptane, dihydrochloride

3.1 g (8.8 mmol) of the alcohol from Example b) are dissolved in 8 ml of tetrahydrofuran, and 2.0 ml (14 mmol) of triethylamine are added at room temperature. 1.02 ml (13 mmol) of methanesulfonic acid chloride are dissolved in 1 ml of tetrahydrofuran and the mixture is stirred at 20 ° C. for five hours. Then drop 8.9 ml

(132 mmol) ethylenediamine at a temperature between 35 ° C and 45 ° C. The mixture is heated to 50 ° C. and the batch is stirred for three hours. Then the reaction mixture is evaporated, the residue is taken up in ethyl acetate and washed with water. The organic phase is cooled in an ice bath and concentrated with. Hydrochloric acid added. The resulting precipitate is filtered off, washed with cold isopropanol and dried at 50 ° C.

Yield: 3.8 g (91.4% of theory) of a yellowish solid.

Analysis (based on solvent-free substance):

calc .: C 58.47 H 7.47 Cl 15.01 N 8.89 0 10.16

found: C 58.28 H 7.24 Cl 14.93 N 8.73

d) 2- [2-butoxybenzyl] -1,4,7-triazaheptane, dihydrochloride 3.6 g (8.1 mmol) of the Z-protected amine from Example c) are added in 35 ml

Methanol suspended, with 0.4 g palladium (10%) on activated carbon and 0.3 ml

Water added and hydrogenated at normal pressure, at room temperature. To When the uptake of hydrogen is complete, the catalyst is filtered off and the filtrate is evaporated.

Yield: 2.4 g (87.6% of theory) of a yellowish solid.

Analysis (based on solvent-free substance):

calc .: C 53.25 H 8.64 Cl 20.96 N 12.42 04.73

Found: C 53.08 H 8.72 Cl 21.23 N 12.29

e) 3,6,9-Triaza-3,6,9-tris (tert-butoxycarbonylmethyl) -4- (2-butoxybenzyl) undecanedioic acid di-tert-butyl ester

5.3 g (38.8 mmol) of kaiium carbonate are dissolved in 5 ml of water and 2.3 g (7.4 mmol) of triamine dihydrochloride (Example d) are added at 35 ° C. 5.9 ml (40.6 mmol) of tert-bromoacetic acid are added. -butyl ester is added dropwise and the mixture is stirred at 60 ° C. for eight hours. After stirring for 15 hours

At room temperature, the reaction mixture is mixed with water and extracted with ethyl acetate. The organic phase is over

Dried sodium sulfate, evaporated and the residue on silica gel

Yield: 5.3 g (85.7% of theory)

Analysis (based on solvent-free substance):

calc .: C 64.64 H 9.28 N 5.03 021.05

Found: C 64.77 H 9.34 N 4.88

f) 3,6,9-Triaza-3,6,9-tris- (carboxymethyl) -4- (2-butoxybenzyl) -undecanedioic acid 5.11 g (6.3 mmol) of pentaester from Example e) are in 40 ml Dissolved methanol and reacted with 2.02 g (50.6 mmol) sodium hydroxide in 3.1 ml water. The mixture is stirred at 55 ° C. for three hours, then the methanol is evaporated off and water is added and evaporate again. It is taken up in water and adjusted to pH 1.9 with an acidic ion exchanger. After filtering off the exchanger, the aqueous solution is largely concentrated and the penta acid is purified by preparative HPLC (water / methanol / pH 2.8). The product-containing fractions are evaporated, taken up again in water and freeze-dried. Yield: 2.9 g (82.8% of theory) of colorless lyophilisate.

Analysis (based on solvent-free substance):

calc .: C 54.05 H 6.71 N 7.56 031.68

Found: C 53.91 H 6.76 N 7.39

g) Gadolinium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (2-butoxybenzyl) -undecanedioic acid

2.48 g (4.7 mmol) of pentic acid from Example f) are suspended in 20 ml of water at 85 ° C. and 0.85 g (2.35 mmol) of gadolinium oxide are added in portions. After complexation is complete, the mixture is filtered, adjusted to pH 7.2, stirred with 0.2 g of activated carbon at 90 ° C. for ten minutes, filtered again and the filtrate is lyophilized.

Yield: 3.5 g (98.8% of theory) of colorless lyophilisate.

Analysis (based on anhydrous substance):

calc .: C 39.84 H 4.28 N 5.58 023.35 Gd 20.86 Na 6.10

Found: C 39.73 H 4.39 N 5.47 Gd 20.71 Na 5.94

Example 15

Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -5- {4- [2- (2-ethoxyethoxy) ethoxy] benzyl} undecanedioic acid a) 3.6 , 9-Triaza-3,6,9-tris (tert-butoxycarbonylmethyl) -5- {4- [2- (2-ethoxyethoxy) ethoxy] benzyl} undecanedioic acid di-tert. -butyl ester

16.7 g (21.4 mmol) 3,6,9-triaza-3,6,9-tris- (tert-butoxycarbonylmethyl) -5- (4-hydroxybenzyl) -undecanedioic acid di-tert-butyl ester ( DOS 3710730) are dissolved in 50 ml of anhydrous N, N-dimethylformamide and 0.94 g (23.5 mmol) of sodium hydride dispersion (60% in mineral oil) are added at 0 ° C. under argon. The mixture is allowed to stir for 15 minutes, then 4.73 g (24.0 mmol) of 2- (2-ethoxyethoxy) ethyl bromide are added, the reaction temperature is allowed to rise to room temperature and the mixture is stirred for a further four hours. The mixture is worked up in toluene

added and shaken several times against aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over magnesium sulfate, filtered and evaporated. The oily residue is chromatographed on silica gel with hexane / diethyl ether / triethylamine, the product-containing

Fractions are pooled and evaporated.

Yield: 17.7 g (92.4% of theory) of colorless oil.

Analysis (based on solvent-free substance):

calc .: C 62.99 H 9.11 N 4.69 O 23.21

Found: C 63.07 H 9.27 N 4.75

b) Ytterbium complex of the disodium salt of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -5- {4- [2- (2-ethoxyethoxy) ethoxy] benzyl} undecanedioic acid

13.4 g (15.0 mmol) of the compound prepared according to a) are in 35 ml

Dissolved tetrahydrofuran and mixed with 45 ml of two normal sodium hydroxide solution, stirred for two hours at 60 ° C, adjusted to pH 1 with concentrated hydrochloric acid, concentrated on Rotary evaporator and clean the residue by ion exchange chromatography (cation exchanger (H ⁺ form), eluent: aqueous

Ammonia solution). The eluate is evaporated and dried under high vacuum, whereby the free complexing agent is obtained.

The penta acid is taken up in 150 ml of water and mixed with 3.94 g (7.5 mmol) of ytterbium carbonate. The suspension is stirred at 60 ° C for 3 hours and filtered. Then pH 7.3 is adjusted with a normal sodium hydroxide solution. The solution is then stirred at 80 ° C. for one hour after the addition of 1.0 g of activated carbon and filtered. After freeze drying, the filtrate gives a colorless solid. Yield 11.4 g (91.6% of theory)

Analysis (based on anhydrous substance):

calc .: C 39.09 H 4.37 N 5.07 025.07 Yb 20.86 Na 5.54

found: C 38.84 H 4.45 N 5.02 Yb 20.69 Na 5.30

Example 16

Density increase of healthy liver parenchyma 10 and 60 minutes after infusion of a 0.25 molar solution of the gadolinium III complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) - undecanedioic acid disodium salt (Gd-EOB-DTPA, described in Example 8c of EP 0405704) in 5 patients with liver metastases in a dose of 0.35 mmol / kg in Houndsfield units (HU). This dose corresponds to approximately 16 g of the complex per 70 kg patient.

In comparison, according to Mützel et al., 1982, the hexajodized SH L 433 (formula XI) developed especially for liver diagnosis caused

at a dose corresponding to 360 mg iodine / kg (approx. 25 g iodine per 70 kg patient) only an enhancement of <10 HU (monkey, dog, mouse:> 40 HU). Lotroxinate (hexajodated, 2 carboxyl groups), which is excreted bilaterally in humans, only reaches 15 HU in the liver at the maximum tolerated dose corresponding to approx. 7 g iodine / 70 kg patient (Hübner, K.H: computed tomography

Densitometry of the liver, spleen and kidneys in intravenous bolus contrast agents. Progress Röntgenstr. 129, 289-297 (1978)).

In comparison, with about 3.5 g of gadolinium in the form of a complex that contains only one gadolinium ion / molecule, it is many times higher

X-ray absorption in the liver of humans achieved as with 25 g iodine of SH L 433 (formula XI) or 7 g iodine of lotroxinate, although both X-ray contrast media are hexajodiert connections.

Example 17

The following solution is produced:

0.1 mol of the holmium (III) complex of 3,6,9-triaza-3,6,9-tris- (carboxymethyl) - 4- (4-butylbenzyl) -undecanedioic acid, dimeglumin salt,

0.005 mol of the calcium (II) complex of 3,6,9-triaza-3,6,9-tris (carboxymethyl) - 4- (4-butylbenzyl) -undecanedioic acid, trimeglumin salt

in 1 liter of 5% mannitol solution, pH 7.0.

The solution is dosed at 0.3 mmol / kg over 30 minutes

Body weight infused. CT scans are performed before the start of the infusion, at the end of the infusion and 30 minutes after the end of the infusion in the usual way.

Example 18

3,6,9-Triaza-3,6,9-tris (carboxymethyl) -4- (4-ethoxybenzyl) -undecanedioic acid disodium salt was complexed with different X-ray absorbing metal ions and then at different concentrations the density values of the samples in a water phantom measured since in the

Dimensions roughly corresponded to a person's abdomen. It was worked on a commercially available computer tomograph with the usual voltage of 137 kV and 110 mA.

A surprisingly high effectiveness of the rare earths against iodine turns out, which is presumably due to the special measuring conditions existing in abdominal CT. Within the lanthanides, erbium, ytterbium and holmium are preferable to the elements gadolinium and dysprosium, which have so far been the most studied.

Example 19

Test execution

Fifteen patients with known liver metastases were examined in liver CT 10 min, 60 min and (N = 5) 120 min after intravenous infusion of 0.2, 0.35 and 0.5 mmol / kg Gd-EOB-DTPA (see Example 16) examined.

Gd-EOB-DTPA (0.25 mmol / L) was administered intravenously in a drip infusion into the arm vein. The infusion time was 20 min for the doses 0.2 and 0.35 mmol / kg and 30 min for the highest dose of 0.5 mmol / kg.

The patients had histologically proven primary tumors (N - 9 with colorectal carcinoma, N = 2 with intestinal carcinoid, N = 1 with gastric carcinoma, N = 1 with leiomyosarcoma and N = 1 with ovarian cystadenocarcinoma) and the metastases (N≤ 5) were complete contrast-enhanced CT was detected within one month prior to the Gd-EOB-DTPA study. Exclusion criteria for the patients were:

● age under 18 years,

● History of severe or allergy-like side effects

Administration of contrast medium,

● previous administration of Gd-EOB-DTPA,

● Contrast agent administration within 24 hours before the study,

● a transplanted organ,

● women before menopause,

● surgery or liver biopsy 24 hours before or after the study and

● Patients with laboratory parameters that deviate greatly from the norm. CT examinations were performed before and 10 min, 60 min and (N = 5) 120 min after intravenous infusion of Gd-EOB-DTPA with a Siemens spiral CT

carried out. The entire liver was measured within 20-30 seconds with the breath stopped. The table feed was 8 mm / sec, the collimation 8 mm.

Based on the pre- and post-contrast images, the number and size of the

Metastases by two independent observers qualitative (excellent, good, moderate, minimal, no improvement) and quantitatively (measurement of the Hounsfield units) evaluated.

The tolerance of Gd-EOB-DTPA was determined by determining the

General condition, the recording of vital parameters and a

Laboratory analysis of serum and urine parameters determined.

Results

After intravenous infusion of Gd-EOB-DTPA, a dose-dependent increase in the CT density of the healthy liver was found. Figure 1 shows the time course of the CT density (Hounsfield units, HU) in the liver of patients with histologically proven primary tumor after the start of an infusion of 0.2 (o), 0.35 (♦) or 0.5 mmol / kg Gd-EOB-DTPA (Λ). The CT density in the liver metastases is shown with the symbol *.

The CT density of the metastases was unchanged. In addition, one succeeded

Illustration of the gallbladder and bile ducts.

Visualization of the metastases was improved in all dose groups after infusion of Gd-EOB-DTPA. It was excellent in the two upper dose groups. After the highest dose, an average of two additional metastases were discovered that were previously unknown. The mean size of the smallest metastases found decreased accordingly from 20.3 to 16.6 mm. In a patient with a known metastasis in the right lobe of the liver, an additional lesion of 7 mm in diameter was found after Gd-EOB-DTPA in the left lobe of the liver, which had not previously been found.

The general tolerability of Gd-EOB-DTPA was good. Only four mild or moderate side effects were observed. They reported in two cases

Patients from or infectiously burning at the infusion site that persisted for a few seconds or minutes. Other side effects included nausea and epigastric pressure. The evaluation of the laboratory parameters showed no clear trend. Slight increases in aspartate and alanine aminotransferase were found in three patients

Liver metastases were caused. In summary, it follows from Example 19 that Gd-EOB-DTPA is a well-tolerated and effective liver or bile contrast agent for computed tomography.

Claims

Claims:

1. Use of metal complexes consisting of a metal

Atomic numbers 39-42, 44-51 or 56-83 and a complexing agent for the production of X-ray contrast media for use in contrast-enhanced computed tomography of the liver and the biliary tract.

2. Use of metal complexes according to claim 1, wherein the

Metal complex has a stability constant of at least 10 and a maximum molecular weight of 1500 daltons.

3. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula I.

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of claim 1

ordinal numbers

k represents the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, a -N (H) - or -N (R ² ) - group or a C ₁ -C ₁₀ alkylene chain, which may be replaced by a

Oxygen or a sulfur atom, an -N (H) - or an -N (R ² ) - group is interrupted,

free carboxyl groups not used for complexation can also be present as salts of physiologically compatible cations or as amides of the forms,

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

4. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula II

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of the atomic numbers mentioned in claim 1

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ - C ₁₀ alkylene chain, which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N (R ² ) - group is interrupted,

wherein the six-membered carbon rings present in formula II can also be aromatic and where free carboxyl groups not used for complexation can also be present as salts of physiologically compatible cations or as an amide of the formula

wherein

R ^{1 has} the meaning given above and

5. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula III

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of the atomic numbers mentioned in claim 1

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ - C ₁₀ alkylene chain, which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted,

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

6. Use of metal complexes according to claim 1, characterized in that the metal complex corresponds to the general formula IV

wherein

independently of one another represents a hydrogen atom or a metal ion equivalent of an element of the atomic numbers mentioned in claim 1

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ - C ₁₀ alkylene chain, which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted, where if m and / or p is zero, no two or more heteroatoms may be directly connected to one another,

wherein

R1 has the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

7. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula V.

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of those mentioned in claim 1

Atomic numbers stands

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

wherein

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

8. Use of metal complexes according to claim .1, characterized

characterized in that the metal complex corresponds to the general formula VI

wherein

X independently of one another for a hydrogen atom or for a

Metal ion equivalent of an element of the atomic numbers mentioned in claim 1

n stands for the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ - C ₁₀ alkylene chain, which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted, where if m and / or p is zero, two or more heteroatoms must not be directly connected to one another and

free carboxyl groups not used for complexation also as salts of physiologically compatible cations or

0 R ¹

can be present as an amide of the formula • C — N, wonn

R ^{1 has} the meaning given above and

at least one of the radicals denoted by R ^{1 has} the meaning of a

Rest of the formula la has.

9. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula VII

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of those mentioned in claim 1

Atomic numbers stands

k represents the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ - C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₅ -C ₁₀ - alkylene chain which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted,

wherein

R ^{1 has} the meaning given above

optionally by one to three phenyl, pyridyl, HO, HS,

10. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula VIII

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element of the atomic numbers mentioned in claim 1

k represents the numbers 0, 1 or 2 and

wherein

m, p stands for the numbers 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ - C ₆ radical and

L ¹ , L ² , L ³ each for a direct bond, an oxygen atom

Sulfur atom, an -N (H) - or -N (R ² ) - group or a C ₁ -C ₁₀ - alkylene chain which may be replaced by an oxygen or a sulfur atom, an -N (H) - or an -N ( R ² ) - group is interrupted, where if m and / or p is zero, two or more heteroatoms must not be directly connected to one another and

wherein

R ^{1 has} the meaning given above and

optionally by one to three phenyl, pyridyl, HO, HS,

11. Use of Metallkompiexen according to claim 1-, characterized

characterized in that the metal complex corresponds to the general formula IX

wherein

X independently of one another for a hydrogen atom, or for a

Metal ion equivalent of an element having the atomic numbers mentioned in claim 1,

R ^{3 represents} a methyl, ethyl, n-propyl, n-butyl or a benzyl radical.

12. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula X.

wherein X independently of one another for a hydrogen atom, or for a

R ^{3 represents} a methyl, ethyl, n-propyl, n-butyl or a benzyl radical.

13. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula XI

X is independently a hydrogen atom or a

Metal ion equivalent of an element of atomic numbers 44-51 or 56-83,

one of the radicals R ^{1 is} a radical of the formula -CH ₂ -C ₆ H ₄ - (O) _r -R ² , in which the aromatic ring can be substituted in the ortho, meta or para position and the other radical R ¹ for Hydrogen stands,

R ² for a hydrocarbon radical consisting of 1-6

in which carboxyl groups can also be present as amides,

together with those required for charge balancing

physiologically acceptable cations.

14. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula XII

wherein

R ^{1 represents} a radical of the formula Ib

wherein

p stands for the number 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical,

Carboxyl group,

X ¹ independently of one another for a group

OX ² with X ² in the meaning given below or for a group

N (R ⁴ ) R ⁵ wherein

15. Use of metal complexes according to claim 1, characterized

characterized in that the metal complex corresponds to the general formula XII

wherein

p stands for the number 0 or 1

R ² independently of one another for a hydrogen atom or a

branched or unbranched, saturated or unsaturated C ₁ -C ₆ radical,

Carboxyl group,

L ² , L ³ each independently for a direct bond

Oxygen atom, a sulfur atom or a C ₁ -C ₁₀ alkylene chain, which optionally contains one to three oxygen and / or one to three sulfur atoms,

where if p is zero two or more heteroatoms must not be directly connected to one another and X ¹ independently of one another for a group

OX ² with X ² in the meaning given below or for a group

N (R ⁴ ) R ⁵ wherein

16. Use of metal complexes according to one of claims 3 to 10, characterized in that the complex contains one or two residues of the formula la.

17. Use of Metallkompiexen according to claim 15, characterized

characterized in that the complex contains one or two radicals of the formula Ic.

18. Use of metal complexes according to one of claims 3 to 10, characterized in that at least one of the radicals of the formula la for -CH ₂ -C ₆ H ₅ , -CH ₂ -C ₆ H ₄ -O-CH ₃ , -CH ₂ -C ₆ H ₄ -O-CH ₂ CH ₃ , -CH ₂ -C ₆ H ₄ - OC ₃ H ₇ , -CH ₂ -C ₆ H ₄ -OC ₄ H ₉ , -CH ₂ -C ₆ H ₄ -OC ₅ H ₁₁ , -CH ₂ -C ₆ H ₄ -O- CH ₂ -C ₆ H ₅ , -CH ₂ -C ₆ H ₄ -CH ₃ , -CH ₂ -C ₆ H ₄ -CH ₂ CH ₂ , -CH ₂ -C ₆ H ₄ -C ₃ H ₇ , -CH ₂ - C ₆ H ₄ -C ₄ H ₉ or -CH ₂ -C ₆ H ₄ -C ₅ H ₁₁ .

19. Use of metal complexes according to claim 14, characterized

characterized in that at least one of the radicals of the formula Ib for

-CH ₂ -C ₆ H ₅ , -CH ₂ -C ₆ H ₄ -O-CH ₃ , -CH ₂ -C ₆ H ₄ -O-CH ₂ CH ₃ ,

-CH ₂ -C ₆ H ₄ -OC ₃ H ₇ , -CH ₂ -C ₆ H ₄ -OC ₅ H ₉ , -CH ₂ -C ₆ H ₄ -OC ₅ H ₁₁ ,

-CH ₂ -C ₆ H ₄ -O-CH ₂ -C ₆ H ₅ , -CH ₂ -C ₆ H ₄ -CH ₃ , -CH ₂ -C ₆ H ₄ -CH ₂ CH ₃ ,

-CH ₂ -C ₆ H ₄ -C ₃ H ₇ , -CH ₂ -C ₆ H ₄ -C ₄ H ₉ or -CH ₂ -C ₆ H ₄ -C ₅ H ₁₁ .

20. Use of metal complexes according to claim 15, characterized

characterized in that at least one of the radicals of the formula Ic for

-CH ₂ -C ₆ H ₄ -OC ₃ H ₇ , -CH ₂ -C ₆ H ₄ -OC ₄ H ₉ , -CH ₂ -C ₆ H ₄ -0-C ₅ H ₁₁ ,

21. Use of metal complexes according to one of claims 3-15,

characterized in that a metal of the lanthanoid series is used as the metal.

22. Use of metal complexes according to one of claims 3-15,

characterized in that gadolinium, dysprosium,

Holmium, erbium, ytterbium or lutetium is used.

23. Use of metal complexes according to one of claims 3-15,

characterized in that a metal of atomic numbers 72-83 is used as the metal.

24. Use of metal complexes according to any one of claims 3-15, characterized in that bismuth, lead or hafnium is used as the metal.

25. Use of metal complexes according to one of claims 3-15, characterized in that a metal of atomic numbers 39-42 is used.

26. Use of metal complexes according to one of claims 3-15, characterized in that a metal of atomic numbers 44-51 is used.

27. Use of metal complexes according to any one of claims 3-15, characterized in that Na ⁺ , Ca ²⁺ , Mg ²⁺ , Zn ²⁺ or a cation of one of the organic bases meglumine as the physiologically compatible cation,

Glucosamine, arginine, ornithine, lysine and ethanolamine is used.