Note: Descriptions are shown in the official language in which they were submitted.
1341 1 76
MACROCYCLIC COMPOUNDS
10
This invention relates to macrocyclic complexing
compounds or agents, complexes of metal ions therewith
(i.e., complex salts) and complex salts of said
complexes, agents, e.g., pharmaceutical agents,
containing these compounds, their use as diagnostics and
therapeutics, as well as to processes for the
preparation of these compounds and agents.
Consideration has been given to the use of metal
complexes as contrast media for radiology as early as
the beginning of the fifties. The compounds then
utilized, however, showed such high toxicity that
administration to human patients could not be
considered. Therefore, the realization was definitely
1341 176 '
- 2 -
surprising that certain complex salts proved to have
adequate compatibility to be considered for routine use
in human patients for diagnostic purposes. As the first
representative of this class of compounds, the
dimeglumine salt of Gd DTPA [the gadolinium (III)
complex of diethylenetriaminepentaacetic acid] described
in European Patent Application, Publication No. 71564
(See United States Patent Number 4,647,447),
has very well proven itself thus far as a
contrast medium for nuclear spin tomography in clinical
testing on more than one thousand patients. The
compound is primarily used in connection with diseases
of the central nervous system.
An important reason for the good compatibility of
Gd DTPA in clinical usage resides in high efficacy in
nuclear spin tomography, especially for many brain
tumors. On account of its high efficacy, Gd DTPA can be
administered, e.g., at 0.1 mmol/kg body weight, at a
very much lower dose than, for example, X-ray contrast
media in many X-ray examinations.
As a further representative of the complex salts,
the meglumine salt of Gd DOTA [gadolinium(III) complex
of 1,4,7,10-tetraazacyclododecanetetraacetic acid], the
subject of United States Patent Number 4,647,447 and
Canadian Patent Number 1,256,249 has proved to be well
suited for diagnostic purposes.
However, it is desirable to employ chelates even in
higher doses. This is the case, in particular for
identification of specific diseases outside of the
central nervous system with the aid of nuclear spin
tomography (NMR diagnostics), but quite especially when
using chelates as X-ray contrast media.
Chelates can offer a number of advantages over
iodinated X-ray contrast media:
(a) Radiation absorption in the higher energy range;
~~~~~!
1341 1 76
- 3 -
thus reduction of radiation stress on patients and
improvement of the prerequisites for the energy
subtraction method.
(b) Avoidance of so-called "allergy-like" or cardio-
vascular side effects, known as "contrast medium
reactions" of the iodinated X-ray contrast agents
used nowadays, which effects are unforeseeable, in
part even life-threatening or fatal.
The preconditions therefore are:
- high concentration of radiation-absorbing
elements in solution (X-ray) or a strong
influence on the NMR signals:
- pharmacokinetics suitable for diagnostics:
- a very firm bond of the metal ions in
excretable complexes, even under in vivo
conditions;
- good compatibility of the highly concentrated,
high-dosage complex solution:
- low allergic potential of all components of
tire contrast medium: and
- high stability and long shelf life of the
chemical ingredients of the contrast solution.
These requirements apply to varying degrees and in
various ways, but basically hold true for all
applications of the aforementioned complexes in in vivo
diagnostics as well as, in part, in therapy.
The present invention provides new such complexes,
preferably which satisfy the foregoing requirements.
Consistent with the present invention there are
provided
_--.
X341 1 76
- 4 -
macrocyclic compounds characterized by general Formula I
U~-~~-(U2-D2) _A1
s
(I)~
U _0~_!U3_03)t_A2
wherein
Y is a nitrogen or phosphorus atom,
Al and A2, being identical or different, each mean a
straight-chain or branched alkylene group of 2-6
carbon atoms,
U1, U2, U3 and U4, being identical or different, each
mean
a direct bond or a straight-chain or branched
alkylene group of 1-6 carbon atoms,
Dl, D2, D3 and D4, being identical or different,
respectively mean an oxygen or sulfur atom, an
alkylene group of 1-6 carbon atoms, or a group N-R~
wherein R~ means a hydrogen atom, a straight-chain
or branched alkylene chain of 1-4 carbon atoms
carrying at the end a COOR1 group with R1 being a
hydrogen atom or a metal ion equivalent,
D5 has one of the meanings given for Dl, D2, D3 and D4
and can also mean
R5
i
the group -CH- wherein R5 means a hydrogen atom or
a straight-chain or branched, saturated or
unsaturated Cl-C20-hydrocarbylene, e.g., alkylene
group, optionally containing imino, phenylenoxy,
phenylenimino, phenylene amide, an ester group
and/or oxygen, sulfur and/or nitrogen, and/or
optionally substituted by hydroxy, mercapto, epoxy,
oxo, thioxm,imino and/or amino group(s), this
alkylene group exhibiting at the end either a
functional group or, linked via the latter, a
macromolecule B,
s and t mean integers from 0 to 5,
1341 176
- 5 -
RZ means hydrogen; a linear or branched, saturated or
unsaturated hydrocarbyl, acyl or acylalkylene group of 1-16
carbon atoms optionally substituted by one or several
hydroxy or lower alkoxy groups; -CH2-X-V wherein X means
carbonyl, a straight-chain or branched-chain alkylene group
of 0-10 carbon atoms, optionally substituted by one or
several hydroxy or lower alkoxy groups; or a straight-chain
or branched-chain alkylene group of 5-23 carbon atoms,
interrupted by oxygen atoms; but wherein formyl is not
1o substituted by hydroxy; V means N~R3 , or -COOR6 wherein
~Rq
R3 and R9, independently of each other, mean hydrogen, a
linear or branched alkyl group of 1-16 carbon atoms
substituted, if desired, by one or several hydroxy or lower
alkoxy groups, or R3 and R4 together with the nitrogen atom
mean a five- or six-membered ring which is saturated and
optionally contains a further hetero atom, and R6 means a
saturated, unsaturated, straight-chain or branched-chain or
cyclic hydrocarbon residue of up to 16 carbon atoms, or an
2o aryl or aralkyl group,
or
RZ or R3 mean a second macrocycle of Formula I',
U~-0~-(UZ-~215-~~
lI~),
which can be of a structure different from the basic
skeleton of the first macrocycle, and which is linked by
way of an alkylene chain containing 2-20 carbon atoms,
30 optionally carrying carbonyl groups at the ends and being
interrupted, if desired, by one or several oxygen atoms or
R1-carboxymethylimino groups or being substituted by one or
1341 1 76
- 6 -
several hydroxy, lower alkoxy or carboxy-lower alkyl
groups,
or RZ means B or CHZ-COB, with the provisos that, if RZ
stands for B or CHZ-COB, R5 is a hydrogen atom; that at
least two COOR1 groups are present in the molecule; and
that there are at least two hetero atoms in the macrocycle
and that two hetero atoms of the macrocycle are linked to
each other by way of an alkylene group with at least two
carbon atoms; and
1o wherein functional groups present in the molecule are, if
desired, conjugated with macromolecules and, if desired,
free carboxy groups are used to form a salt with organic or
inorganic bases or amino acids, and/or alkaline groups and
are used to form a salt with inorganic or organic acids.
In particular, 1,4,7,10-tetraazacyclododecane
derivatives of general Formula II are preferred
R2
R ~ 0 0 C--~~N/
(II),
R ~ OOC-/N~/N~COOR ~
wherein:
each R1, independently of each other, is hydrogen or a
metal ion equivalent of a complexible metal;
RZ is a linear or branched, saturated or unsaturated
hydrocarbyl, acyl or acyl-alkylene group each of 1-16
carbon atoms substituted by from 1 to 10 hydroxy or lower
alkoxy groups, or -CH2-X-V wherein
X is carbonyl, alkylene of 0-10 carbon atoms,
optionally substituted by hydroxy and/or lower alkoxy,
or alkylene of 5-23 carbon atoms interrupted by oxygen
atoms,
V is _N--""~R3 or -COOR6, wherein
r.~ ~ ~~4
1341 1 76
R3 and R4, independently of each other, each is
hydrogen, alkyl of 1-16 carbon atoms, or alkyl of
1-16 C-atoms substituted by hydroxy and/or lower
alkoxy, or
R3 and R4 together with the connecting nitrogen
atom form a five- or six-membered saturated ring
which can also contain an additional hetero N, S
or O atom, and
R6 is aliphatic hydrocarbyl of up to 16 carbon
to atoms, C6-io-aryl or C6-io-ar-C1_4-alkyl,
or
R2 or R3 represent a second macrocycle of Formula II',
R ~ 0 0 C--~N~N~
(II~),
R~OOC-/N~N~COOR2
which is of a structure the same as or different from that
of the basic skeleton of Formula II,
20 linked by way of an alkylene chain containing 2-20 carbon
atoms which optionally carries carbonyl groups at its ends
and/or optionally is interrupted by oxygen or R1-
carboxymethylimino and/or optionally is substituted by
hydroxy, lower alkoxy or carboxy-lower alkyl,
or
RZ is B or CHZ-COB, wherein B is a biomolecule or synthetic
polymer that accumulates to an especially great extent in
the organ or organ part to be investigated or in a tumor,
and functional groups present in the molecule are, if
3o desired, conjugated with biomolecules and optionally free
carboxy groups are used to form a salt with organic or
inorganic bases or amino acids, and alkaline groups are
used to form a salt with organic or inorganic acids.
~' > ,
~,:.3
1341 17fi
_8_
The compounds of this invention and the
solutions prepared therefrom fulfill the cited require-
ments in a surprising way. They exhibit a high efficacy
that can be adapted, by the choice of suitable metal
atoms, to the respective principles of the diagnostic
or therapeutic method (X-ray, NMR, ultrasonics, nuclear
medicine).
The compounds of this invention are utilized, e.g.,
1. For NMR diagnostics in the form of their
complexes with the ions of the transition
metals of atomic numbers 21-29, 42 and 44.
2. For NMR and X-ray diagnostics in the form
of their complexes with the ions of the
lanthanide elements of atomic numbers 57-70.
3. For ultrasonic diagnostics, those compounds
can be employed which are useful in NMR
diagnostics, as well as those useful in
X-ray diagnostics.
4. For radiodiagnostics and radiotherapy in
'6 the form of their complexes with the
radioisotopes of the elements of atomic
numbers 27, 29, 31, 32, 38, 39, 43, 49,
62, 64, 70 or 77.
_ Q _ 1341 1 76
J
Even without specific measures, their pharma-
cokinetics permit improvement in the diagnosis of
numerous diseases. The complexes, for the largest
part, are excreted unchanged and quickly so that
especially when using relatively toxic metal ions as
the active principle, no damaging effects that can be
traced back to the metal are observed, in spite of a high
dosage.
Practical usage of the novel complexes and
complexing agents is also facilitated by their adequate,
frequently even .very gobd~ :chemicalwstability.
Another essential advantage of the complexes
and complexing agents described resides in their extra-
ordinary chemical versatility. Besides by the choice of
the central atom, the properties can be adapted by the
choice of variegated substituents and/or salt-forming
agents to the requirements regarding efficacy, pharmaco-
kinetics, compatibility, ability to handle, etc.
Thus, it is possible to attain a specificity of the
compounds, very desirable in diagnostics and therapy,
for structures in the organism, for certain biochemical
substances, for metabolic processes, for conditions
prevailing in tissue or body fluids, especially by
coupling to biological compounds or to compounds
exhibiting interaction with biological systems.
Such compounds suitable for coupling can be of low
molecular weight (for example, glucose, amino acids, fatty
acids, bile acids, porphyrins) or high-molecular weight
(polysaccharides, proteins, antibodies, etc.), or they
can also represent structures foreign to the body
but exhibiting a specific way of distribution in the
body or reacting with components of the body.
. 1341 1 76
- to -
Utilization of such principles will be possible
the more easily, the more sensitive the detection
method for a diagnostic agent, or the more effective
a complex, being, for example, labeled radioactively,
in therapy.
The compounds of this invention can also be
used in radiotherapy in the form of their complexes
with radioisotopes, e.g. 192Ir. The complex-forming
agents of this invention are furthermore suited,
as such or in the form of weak complexes with preferably
endogenous ions (Ca2+, Mg2+, Zn2+~ ge2+/3+
for therapy
of heavy metal poisoning or storage disea~~rs.
More generally, the compounds can be used
in conjunction with any metal ion equivalent as
long as the metal is chelatable (complexable) by a
complexing agent.of this invention. Thus, the compounds,
complexes and complex salts of this invention are
also useful for the purposes known in the past for
complexes of such metal ions.
1341 1 76
- 11 -
Y preferably is N. Suitable alkylene groups
throughout the foregoing depending on the number of C-
atoms, include, e.g., straight-chained and branched
methylene, ethylene, propylene, butylene, pentylene,
hexylene, heptylene, octylene, nonylene, decylene,
undecylene, etc.
D's are preferably N-R~.
Compounds of general Formula I wherein R1 is
hydrogen are denoted as complexing compounds, and those
wherein at least two substituents R1 are metal ion
equivalents are called metal complexes.
When R2 is hydrocarbyl, acyl or acylalkylene of
1-16 carbon atoms, this group can be linear or branched,
saturated or unsaturated and can optionally be
substituted by one or several hydroxy and/or lower
alkoxy groups. Suitable lower alkoxy groups contain 1-4
carbon atoms and include, in particular, methoxy and
ethoxy groups, but also n- or i-propoxy and n, i, or t-
butoxy.
Suitable hydrocarbyl substituents for each of R2,
R3, R4 and R6 as appropriate per above include saturated
(alkyl), unsaturated (e. g., alkenyl)
straight- or branched-chain or cyclic hydrocarbons of up
to 16 carbon atoms, preferably saturated hydrocarbons
1341 1 76
- 12 -
which, in the case of R2, R3 and R4 are optionally
substituted by 1-5 hydroxy and/or lower alkoxy groups.
Where the group is unsaturated, there typically are 1-3
unsaturated bonds. Examples of optionally substituted
groups include methyl, ethyl, 2-hydroxyethyl, 2-hydroxy-
1-(hydroxymethyl)ethyl, 1-(hydroxymethyl)-ethyl, propyl,
isopropenyl, 2- and 3-hydroxypropyl, 2,3-
dihydroxypropyl, butyl, isobutenyl, 2-, 3- and 4-
hydroxybutyl, 2-, 3- and 4-hydroxy-2-methylbutyl, 2- and
3-hydroxyisobutyl, 2,3,4-trihydroxybutyl, cyclohexyl and
2-methoxyethyl. "Acyl" typically is alkanoyl and
benzoyl. Examples of optionally substituted acyl groups
are the acetyl, methoxyacetyl, propionyl, 2-
hydroxypropionyl, butyryl, 2,3-dihydroxybutyryl, benzoyl
and valeryl groups: examples of optionally substituted
acylalkylene groups include the phenacyl or p-
phenylphenacyl groups, which can be, for example, alkyl
(e.g. of 1-4 C-atoms)- or halogen (F, C1, Br, I)-
substituted in the phenyl ring (e. g., 1-2 times),
acetonyl, 2-oxobutyl, 2-oxopentyl, 2-oxohexyl, etc.
Preferred are hydrocarbyl and acyl groups of 1-7
carbon atoms and 1-4 hydroxy groups.
In X (as well as in R3 and/or R4) the number of the
OH and/or lower alkoxy groups also is 1-5p the number of
interrupting oxygen (oxa) atoms in X is typically 1-7
and, of course, the oxa atoms are non-adjacent.
R6 can also stand for C6-10 aryl or C6_10 ar-C1_4
alkyl, e.g., phenyl or benzyl.
Lower alkoxy groups throughout are to contain in
each case 1-4 carbon atoms and encompass, e.g., in
particular, methoxy and ethoxy groups but also propoxy
and butoxy.
' ' 1341 176
- 12 a-
Throughout, unsubstituted alkyl groups of 1-7 carbon
atoms are preferred, such as, for example, the methyl,
ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl
and hexyl groups. Furthermore preferred are mono- and
polyhydroxy-substituted alkyl groups of 2-7 carbon
atoms and 1-5, preferably 1-4 hydroxy groups, such as,
for example, 2- and 3-hydroxypropyl, 1,3-dihydroxy-
isopropyl, 1-(hydroxymethyl)ethyl, bis- and tris-
(hydroxymethyl)methyl, 2,3-dihydroxy-1-hydroxymethyl-
propyl, 2,3,4,5,6-pentahydroxyhexyl and, preferably,
2-hydroxyethyl, 2-hydroxy-1-(hydroxymethyl)ethyl,
2,3-dihydroxypropyl, and 2,3,4-trihydroxybutyl.
Furthermore preferred are alkyl groups of 5-23 carbon
atoms interrupted by oxygen atoms, e.g..2-[(,e~ -methoxy-,
ethoxy- , mono-, di-, tri-, tetra-, penta-, hexa-
(ethoxy)Jethyl or 3-[Cad-methoxy-, ethoxy-, mono-, ...,
hexa(propoxy)Jpropyl.
When R3 and R4 represent jointly with the nitrogen
atom a saturated five- or six=membered ring optionally
containing a further hetero atom, e.g., N, O or S,
preferably N or O,
~ R3
-N ~ R4 stands preferably for pyrrolidine, piperidine,
morpholine or piperazine.
In case R~ stands for a straight-chain or branched
alkylene chain containing a COOR1 group at the end, such
chain comprises 1-4 carbon atoms; the methylene group is
preferred.
The alkylene chain (K) to which the second
macrocycle I' is linked carries at the ends optionally
carbonyl groups (-CO-K-CO-) and contains 2-20 carbon
atoms. This chain can be interrupted by one or several
(e. g., 1-7) oxygen atoms) and/or carboxymethylimino
13 41 i
- 13 -
groups) and can be substituted by one or several (e. g.,
1-5) hydroxy, lower alkoxy and/or carboxy-lower alkyl
group(s). Lower alkoxy and lower alkyl groups are to
contain respectively 1-4 carbon atoms and comprise, in
particular, methoxy, ethoxy, methyl and ethyl groups.
K is a straight- or branched-chain alkylene group
interrupted, if desired, by one or several oxygen atoms
and/or carboxymethylimino groups, and optionally
substituted as described, can contain 2-20 carbon atoms
and optionally 2-4 oxa atoms and/or 1-3
carboxymethyliminogroups. Furthermore, the alkylene
chain K can be substituted by 1-5 hydroxy, alkoxy or
carboxy-lower alkyl groups.
Examples of K are:
-(CH -CH -0-CH -CH )-, -(CH -0-CH ) -,
-(CH2)2-, -CHZ-0-CH2-, -(CH2)4-. 2 2 2 2 2 2 2
-CH -CH -(0-CH -CH ) -, -CH -CH -(0-CH -CH ) -,
-(CHZ-0-CH2)3-. 2 2 2 2 3 2 2 2 2 4 -CH2 CH-.
OH
-- 0 N
-~H-~H-, -CH2-i-, -CH2-~H-iH-CHZ.
OH OH CN2-COOH OH OH
-CHZ-N-CH2-CH2-N-CH2-CH2-N-CHZ-
~H2 ~H2 ~H2
COOH COOH COOH
. 1341 1 76
- 14 -
The alkylene group contained in R5 can be straight-
chain, branched, cyclic, aliphatic, aromatic or
arylaliphatic and can contain up to 20 carbon atoms,
Straight-chain mono- to hexamethylene groups are
preferred, as well as C1-C4-alkylenephenylene groups.
If the alkylene group contains a phenylenoxy group then
the latter is preferably linked in the p-position via a
methylene group to the -CH-group of the basic skeleton
of the compound of general Formula I. The mentioned
aromatic nature of an R5 alkylene group will be derived
from the mentioned phenylenoxy, phenylene, and/or
phenylenimino groups. Typically, the R5 chain can
contain up to 4 of the mentioned interrupting groups,
e.g., oxa, phenylenoxy, etc.., and 1-5 of the mentioned
substituents.
Preferred functional groups present at the end of
the R5-alkylene group are, for example, the
benzyl ester, ethyl ester, tert-butyl ester, amino,
C1-C6-alkylamino, aminocarbonyl, hydrazine, hydrazino-
carbonyl, maleimido, methacrylamido, methacryloyl-
hydrazinocarbonyl, maleimidamidocarbonyl, halo, mercapto,
hydrazinotrimethylenehydrazinocarbonyl, aminodimethyl-
eneamidocarbonyl, bromocarbonyl, phenylenediazonium,
isothiocyanate, semicarbazide, or thiosemicarbazide
group.
- 15 - 1341 1 76
For explanatory purposes, several selected
R5 substituents will be set forth below:
0
0y
_CH2_C6H4-0(CH2)3-N ~ ~ -CH2-C6H4-0(CH213NH~C
I
0
-CHZ-CSH;-0-CHZ-C02GH2C6H~,
-CHZ-CSN4-0(CH2)5COZCH2CSFi5, 0
-CHZ-C6H~-0(CH2)SCONHNH2, -CH2-C6H4-CONHNH~ , -C~z-C6H4-0(CH2)4-SH,
N -C H -0(CH 1 NHNH , -CH2-CSH4-OlCH2)5-CO~IH-N ~ , -CHZ-C6H4-0(CNZ)38r,
C 2 6 4
0
-CH2-CSH4-0(CHZ)SCONHNH-(CH2)3-NHNH2, -CH2-NHNHZ, -CHZ-SH, -CH2CONHNH2,
-(CH2)3SH, -CHZ-C6H4-0-CH2COBr, -CSH4NHCOCH28r,
II -CH -C H -NN , -C H -N , -C H NHCS,
-CH2-C6H4-OCH2-C-NH-(CHZ)ZNH2, 2 6 4 2 6 4 2 6 4
0
II CH ) -S-SJ ~ ~I , -NHCO-NH-NH2, -NHCS-NH-NHZ,
-CH2-C6H4-NH-C-( 2 2
0
~D~ II
-CH -C H -0-CH2-Ct!-CH2, -CHZ-C6H4-0-CH2-IC-NH-(CH21~0-C-NHNH2,
2 6 4 0 CH
0
II I 3
-CH -C6H;-0-CH2-CHOH-CHZ-NH(CH2))0-IC-NHNH2, -OCH2-C-N-CH2-(CHOH)4-CHZOH,
2
0
0
-CH2-CH-CH2, -CH2-0-(CHZ)3-N ~, -CH2-0-(CH2)~-SH,
I
0 0
-CH2-D-(CHZ)3-NHNHZ, -CHZ-0-CHZ-IC-NH-NHZ, -CHZ-0-CH2-CH2-NHZ,
0 0
H -0-CH -NH-IC-(CH ) -S-S~~N~I , CN -0-CHZ-IC-NH-(CH2)~0-IC-NH-NH2,
G 2 2 2 2 2
,z;
1341 176
".~i - 16 -
.,
If not all acidic hydrogen atoms are sub-
stituted by the central ion, then one, several or all
remaining hydrogen atoms) can be replaced by cations
of inorganic and/or organic bases or amino acids.
Suitable inorganic cations are, for example, the
.s
lithium ion, the potassium ion, the calcium ion and,
in particular, the sodium ion. Suitable cations of
organic bases are, inter alia, those of primary,
secondary or tertiary amines, e.g. ethanolamine, di-
ethanolamine, morpholine, glucamine, N,N-dimethyl-
' glucamine and especially N-methylglucamine. Suitable
cations of amino acids are, for example, those of
, lysine, of arginine and of ornithine.
The complex compounds can also be linked to
macromolecules, preferably to one known to be partic-
ularly .accumulated in the organ or organ part to be
investigated. Such macromolecules include, fo r example,
hormones, dextrans, polysaccharides, polychelones,
hydroxyethyl starch, polyethylene glycol, desferriox-
amines, bleomycins, insulin, prostaglandins, steroid
hormones, amino sugars, amino acids, peptides, such as
polylysine, proteins (such as, for example, immuno-
globulins and monoclonal antibodies) or lipids (also
in the form of liposomes). Conjugates with albumins
deserve special mention, such as human serum albumin, with
antibodies, such as, for example, monoclonal antibodies
specific for tumor-associated antigens or antimyosin.
Instead of the biomolecules; it is also possible to
link suitable synthetic polymers, such as poly-
ethylenimines. The diagnostic media formed there-
from are suited, for example,'for use in tumor and
1341 1 76
- 17 -
infarction diagnostics. Especially suitable monoclonal
antibodies for conjugation are those directed against
predominantly cell-membrane-fixed antigens.
Suitable as such antibodies are, for example,
monoclonal antibodies and/or their fragments [F(ab)2]
for tumor imaging, directed, for example, against the
carcinoembryonal antigen (CEA), human chorionic
gonadotropin (S-hCG), or other tumor-fixed antigens,
such as glucoproteins. Also suitable, inter alia,
are anti-myosin, anti-insulin and anti-fibrin
antibodies.
Suitable for liver tests and/or for tumor
diagnostics are, for example, conjugates or
clathrates with liposomes (used, for instance, as uni-
laminar or multilaminar phosphatidylcholine-cholesterol
vesicles).
All of these conjugations to macrobio-
molecules can be effected fully conventionally.
' 1341 1 76 ._
- is -
The macrocyclic compounds of general
Formula I are produced in that, in a manner known
per se, in compounds of general Formula III
/U~-D1.-IUZ-D2.)S-AI
D5 ~y_R2~ tIII)~
\U;-D4.-(U3-D3.)t-A
wherein
Y, A1, A~, Ul, U2, U3, U4, s and t have the meanings
given above,
D1 , D2 , D3 and D4 have the same meanings as Dl,
D2, D3 and D4 but contain, in place of the COORl
group, the COOZ group wherein Z means a carboxy
blocking group,
has the meanings given for D1~, D2~, D3~ and D4~, ,
and also represents the group R5
-~H-
wherein R5 means R5, but without exhibiting a
macromolecule B, and
R2 has the meanings given for R2, but is not to stand
for a macromolecule B or the group CH2-COB,
- 19 -
1341 176
the blocking groups Z are split off and the resultant
acids (Rl of general Formula I means hydrogen), if
desired
(a) are conventionally reacted with at least one
metal oxide or metal salt of an element of atomic
numbers 21-29, 31, 32, 38, 39, 42-44, 49, 57-70 or
77 and subsequently, if desired, any present acidic
hydrogen atoms are converted into physiologically
compatible salts with inorganic and/or organic bases
or amino acids, and any present alkaline groups are
converted into physiologically compatible salts with
inorganic or organic acids;
or
(b) are conventionally reacted with at least one
metal oxide or metal salt of an element of atomic
numbers 21-29, 31, 32, 38, 39, 42-44, 49, 57-70 or 77
and subsequently the thus-obtained metal complexes,
in a manner known per se, are linked by way of functional
groups contained in the molecule, or by way of R2
or, respectively, by way of the CO-group contained in R' 'to
a macrocycle , and, if desired, any present acidic
hydrogen atoms are converted into physiologically
compatible salts with inorganic and/or organic bases
or amino acids, and any present alkaline groups are
converted into physiologically compatible salts with
inorganic or organic acids;.
or
._ a_.. .~o.;~;.~.«; t. . ~ ~,... . ~. .
1341 1 76
- 20 -
(c) are conventionally linked by way of the
functional groups contained in the molecule, or
by way of R2 or, respectively, by way of the CO-group contained
in R2 to a macrocycle /and subsequently are
conventionally reacted with at least one metal
oxide or metal salt of an element of atomic numbers
21-29, 31, 32, 38, 39, 42-44, 49, 57-70 or 77 and
thereafter, if desired, any present acidic hydrogen
atoms are converted into physiologically compatible
salts with inorganic and/or organic bases or amino
acids, and any present alkaline groups are
converted into physiologically compatible salts
with inorganic or organic acids.
1341 1 76
- 21 -
Carboxy blocking groups Z that can be used
are lower alkyl, aryl and aralkyl groups, for example
the methyl, ethyl, propyl, butyl, phenyl, benzyl,
diphenylmethyl, triphenylmethyl, bis(p-nitrophenyl)methyl
group, as well as trialkylsilyl groups.
Cleavage of the blocking groups Z takes place in
a manner known per se, for example by hydrolysis,
alkaline saponification of the esters, preferably
with an alkali in an aqueous-alcoholic solution at
temperatures of 0° to 50° C or, in case of, for example,
tert-butyl esters, with the aid of trifluoroacetic acid.
The educts are prepared by cyclizing of two
5"
reactants, one of which is R -substituted, wherein
5" 5'
R stands for a substituent convertible into R ;
the thus-obtained cyclic compounds are subsequently
reacted, optionally after splitting off blocking groups,
with halogen alkanes, halogen esters, halogen acids,
halogen ketones, acyl halogenides or acyl anhydrides in
order to introduce. the substituent R2.
The cyclization is performed according to
methods known in the literature (for example, Org.
Synth. 58 . 86 [1978], Macrocyclic Polyether Syntheses,
Springer Publishers, Berlin, Heidelberg,New York, 1982,
Coord. Chem. Rev. 3 . 3 [1968], Ann. Chem. 1976 . 916):
one of the two reactants carries at the end of the
chain two fugitive groups, the other carries two
nucleophiles displacing these fugitive groups.
An example that can be cited is the reaction of end-
positioned dibromo-, dimesyloXy-, ditosyloxy- or
dialkoxycarbonylalkylene compounds optionally con-
taining hetero atoms with end-positioned diaza-
alkylene compounds optionally containing additional
hetero atoms in the alkylene chain, of which
5"
one of the two reactants is R -substituted.
Nitrogen atoms present are optionally blocked,
for example in the form of tosylates, and are liberated
1341 1 76
_ 22 _
prior to the subsequent alkylation reaction in
accordance with methods known from the literature.
If diesters are used in the cyclization
reaction, the thus-obtained diketo compounds must be
reduced by methods known to those skilled in the art,
for example with diborane.
The subsequent alkylation takes place with
halogen ketones, halogen esters, halogen acids or
halogen alkanes which can be substituted by one or
several hydroxy or lower alkoxy groups and may contain
oxygen atoms) in the chain. Furthermore, the alkyl
residue can also contain an end-positioned amino
group.
If alkylation takes place with a dihalogenated
alkane, compounds of general Formula III are produced
having two macrocyclic rings joined by way of a
carbon bridge.
Additional methods known from the literature
for the synthesis of compounds having more than one
ring are, for example, reactions of an amine with
a carbonyl compound (e. g. the acid chloride, mixed
anhydride, activated ester, aldehyde); of two amine-
substituted rings with a dicarbonyl compound (e. g.
oxalyl chloride, glutaric dialdehyde~; of two rings each
exhibiting a nucleophilic group with an alkylene com-
pound carrying two fugitive groups; in case of
terminal acetyls, oxidative coupling (Cadiot,
Chodkiewicz in Viehe "Acetylenes", 597-647, Marcel
Dekker, New York, 1969). The, chain linking the rings
can subsequently be modified by secondary reactions (e. g.
hydrogenation).
The saponification of the ester groups
obtained during alkylation with halogen esters, which
may be necessary, is performed according to methods
known to those skilled in the art (for example with
' ' 1341 176 '
- 23 -
alkaline catalysts, such as alkali or alkaline earth
carbonates or hydroxides).
In the alkylation with haloacetic acid, an
intermediate product is obtained wherein R2 -
CH2X-COON; this product is converted into the monoamide
by way of the mixed anhydride with chloroformic acid
ester or.with the aid of dicyclohexylcarbodiimide and
reaction with a primary or secondary amine of the
general formula ~ R3 .
HN 4
~ R
Examples for suitable amines are: dimethyl-
amine, diethylamine, di-n-propylamine, diisopropyl-
amine, di-n-butylamine, diisobutylamine, di-sec-
butylamine, N-methyl-n-propylamine, dioctylamine,
dicyclohexylamine, N-ethylcyclohexylamine, diisopropenyl-
amine, benzylamine, aniline, 4-methoxyaniline, 4-
dimethylaminoaniline, 3,5-dimethoxyaniline, morpholine,
pyrrolidine, piperidine, N-methylpiperazine, N-ethyl-
piperazine, N-(2-hydroxyethyl)piperazine, N-(hydroxy-
methyl)piperazine, piperazinoacetic acid isopropylamide,
N-(piperazinomethylcarbonyl)morpholine, N-(piperazino-
methylcarbonyl)pyrrolidine, 2-(2-hydroxymethyl)-
piperidine, 4-(2-hydroxyethyl)piperidine, 2-hydroxy-
methylpiperidine, 4-hydroxymethylpiperidine, 2-hydroxy-
methylpyrrolidine, 3-hydroxypiperidine, 4-hydroxy-
piperidine, 3-hydroxypyrrolidine, 4-piperidone, 3-
pyrroline, piperidine-3-carboxylic acid amide, piper-
idi.ne-4-carboxylic acid amide, piperidine-3-carboxylic
acid diethylamide, piperidine-4-carboxylic acid di-
methylamide, 2,6-dimethylpiperidine, 2,6-dimethyl-
morpholine, N-acetylpiperazine, N-(2-hydroxypropionyl)-
piperazine, N-(3-hydroxypropionyl)piperazine, N-
(methoxyacetyl)piperazine, 4-(N-acetyl-N-methylamino)-
piperidine, piperidine-4-carboxylic acid
1341 176
- 24 -
(3-oxapentamethylene)amide, piperidine-3-carboxylic
acid (3-oxapentamethylene)amide, N-(N',N'-dimethyl-
carbamoyl)piperazine, pyrazoline, pyrazolidine, imid-
azoline, oxazolidine, thiazolidine, 2,3-dihydroxypropyl-
amine, N-methyl-2,3-dihydroxypropylamine, 2-hydroxy-1-
(hydroxymethyl)ethylamine, N,N-bis(2-hydroxyethyl)amine,
N-methyl-2,3,4,5,6-pentahydroxyhexylamine, 6-amino-2,2-
dimethyl-1,3-dioxepin-5-ol, 2-hydroxyethylamine,
2-amino-1,3-propanediol, diethanolamine, ethanolamine.
The polyhydroxyalkylamines can advantageously be
used for the reaction also in the blocked form, for ex=
ample as O-acyl derivatives or as ketals. This is
applicable especially if these derivatives can be pro-
duced more conveniently and cheaply than the poly-
hydroxyalkylamines proper. A typical example is
2-amino-1-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol, the
acetonide of 1-amino-2,3,4-trihydroxybuta~e, produced
in accordance with DOS 31 50 917 published June 30, 1983.
The subsequent removal of the blocking groups
does not entail any problems and can take place, for
example, by treatment with an acidic ion exchanger in
an aqueous-alcoholic solution.
Acylation is performed with a corresponding
acyl derivative, especially with an acyl halogenide or
anhydride. When using anhydrides or halogenides of di-
or polycarboxylic acids, then compounds of general
Formula III are obtained wherein the two macrocyclic
rings are linked in the manner of an amide by way of
a carbon bridge.
Suitable as substituents RS~~ convertible into
the substituents R5 exhibiting at the end a functional
group suited for linkage to a macromolecule are, inter
alia, hydroxy and nitrobenzyl, hydroxy and carboxy-
alkyl, as well as thioalkyl residues of up to 10 carbon
~~ ~ ,s..J .
1341 1 76
- 25 -
atoms. They are converted in accordance with methods
disclosed in the literature and known to those skilled
in the art CChem. Pharm. Bull. 33 . 674 [1985],
Compendium of Org. Synthesis vol. 1-5, Wiley and Sons,
Inc.) into the desired substituents (e.g. with the
amino, hydrazino, hydrazinocarbonyl, methacryloyl-
hydrazinocarbonyl, maleimidamidocarbonyl, halogeno,
halogenocarbonyl, mercapto group as the functional
group); in case of the nitrobenzyl residue, a catalytic
hydrogenation (e. g. according to P.N. Rylander,
Catalytic Hydrogenation over Platinum Metals, Academic
Press 1967) must first be performed to obtain the
aminobenzyl derivative.
Examples for the conversion of hydroxy or amino
groups bound to aromatic or aliphatic residues are the
reactions performed in anhydrous, aprotic solvents, such
as tetrahydrofuran, dimethoxyethane or dimethyl sulf-
oxide in the presence of an acid captor, such as, for
example, sodium hydroxide, sodium hydride or alkali
or alkaline earth carbonates, e.g. sodium, magnesium,
potassium, calcium carbonate, at temperatures of
between 0° C and the boiling point of the respective
solvent, but preferably between 20° C and 60° C,
with a substrate of general Formula IV
W-L-Fu (IV)
wherein W is a nucleofugic entity, such as, for ex-
ample, C1, Br, I, CH3C6H4S03 or CF3S03; L is an
aliphatic, aromatic, arylaliphatic, branched, straight-
chain or cyclic hydrocarbon residue of up to 20 carbon
atoms; and Fu is the desired end-positioned functional
group.
' 1341 1 76
- 26 -
Examples of compounds of general Formula IV
are
Br(CH2)2NH2, 8r(CHZ)30H, BrCH2C00CH3, BrCH2C02tBu,
Br(CH2)4C02C2H5, BrCH20COBr, 8rCH2CONH2, C1CH2COOC2H5,
BrCH2CONHNH2, BrCH2-CH-CH2, CF3S03(CHZ)3Br, 8rCH2C=CH, BrCH2CH=CH2.
Conversions of carboxy groups can be conducted,
for example, according to the carbodiimide method
(Fieser, Reagents for Organic Syntheses 10, 142) via a
mixed anhydride (Org. Prep. Proc. Int. 7 . 215 [1975])
or via an activated ester (Adv. Org. Chem. Part B, 472).
The compounds of general Formula I wherein
Rl is a hydrogen atom represent complex-forming com-
pounds. They can be isolated and purified or, without
isolation, can be converted into metal complexes of
general Formula I wherein at least two of the substi-
tuents Rl mean a metal ion equivalent.
The metal complexes of this invention are
prepared as disclosed in the references cited above
by dissolving or suspending the metal oxide or a metal
salt (e. g. the nitrate, acetate, carbonate, chloride
or sulfate) of the element of atomic numbers 21-29, 31,
32, 38, 39, 42-44, 49, 57-70 or 77 in water and/or
a lower alcohol (such as methanol, ethanol or iso-
propanol) and reacting with a solution or suspension
of the equivalent amount of the complex-forming acid
of general Formula I wherein Rl means a hydrogen atom,
and subsequently, if desired,'substituting any present
acidic hydrogen atoms of acid groups by cations of
inorganic and/or organic bases or amino acids.
Neutralization takes place in this process with the aid
of inorganic bases (e.g. hydroxides, carbonates or
bicarbonates) of, for example, sodium, potassium or
lithium and/or with the aid of organic bases, such as,
_ 1341 176
inter alia, primary, secondary and tertiary amines,
such as, for example, ethanolamine, morpholine, glucamine,
N-methyl- and N,N-dimethylglucamine, as well as alkaline
amino acids, such as, for example, lysine, arginine and
ornithine.
In order to prepare the neutral complex
compounds, it is possible, for example, to add to the
acidic complex salts, in an aqueous solution or sus-
pension, such an amount of the desired bases that the
neutral point is reached. The resultant solution can
then be concentrated to dryness under vacuum. It is
frequently advantageous to precipitate the thus-formed
neutral salts by adding water-miscible solvents, such
as, for example, lower alcohols (methanol, ethanol,
isopropanol and others), lower ketones (acetone and
others), polar ethers (tetrahydrofuran, dioxane,
1,2-dimethoxyethane and others) and thus to obtain
crystallized products which can be readily isolated
and easily purified. It proved to be particularly
advantageous to add the desired base to the reaction mixture as
early as during the complex formation and thereby to
save a process step.
If the acidic complex compounds contain
several free acidic groups, it is often advantageous
to prepare neutral mixed salts containing inorganic
as well as organic cations as counterions.
This can be done, for example, by reacting
the complex-forming acid in an aqueous suspension or
solution with the oxide or salt of the element yielding
the central ion and half the amount,required for
neutralization,of an organic base; isolating the thus-
formed complex salt; purifying same if desired; and
then combining same, for complete neutralization, with
the needed amount of inorganic base. The sequence of
adding the bases can also be reversed.
1341 1 7fi '
- 28 -
Alkaline groups can be converted into
pharmaceutically compatible salts with inorganic
and/or organic acids.
Examples for suitable inorganic bases are
lithium, sodium and potassium hydroxide. Organic bases
are, inter alia, primary, secondary and tertiary amines,
such as, for example, ethanolamine, morpholine,
glucamine, N-methyl- and N,N-dimethylglucamine, as
well as alkaline amino acids, such as, for example,
lysine, arginine and ornithine.
Inorganic acids, e.g, hydrochloric acid, and
organic acids, e.g. citric acid, can be used for forming
the salt with alkaline groups.
Conjugate formation can be effected, for ex-
ample, by way of a carboxy group of the complex compound
or by way of the functional group, as defined hereinabove,
present at the end of the C1-C20-alkylene group of sub-
stituent R5. When forming the conjugate of acids with
macromolecules, several acid residues can be bound to the
latter. In this case, several central ions can be bound
to a macromolecule.
Coupling to the desired macromolecules like-
wise takes place according to conventional methods as
disclosed, for example, in Rev. Roum. Morphol. Embryol.
Physiol., Physiologie 1981, 18 . 241 and J. Pharm. Sci.
68 . 79 (1979), for example by reacting the nucleophilic
group of a macromolecule, such as the amino, phenol,
sulfhydryl, aldehyde or imidazole group, with an
activated derivative of the complexing compound. Ex-
amples of activated derivatives are monoanhydrides,
acid chlorides, acid hydrazides, mixed anhydrides (see,
for example, G.E. Krejcarek and K.L. Tucker, Biochem.
Biophys. Res. Commun. 1977, 581), activated esters,
nitrenes or isothiocyanates. Conversely, it is also
possible to react an activated macromolecule with the
.... ..r~W .~... ~.~~*...., ..*,~,..,.. .*_..., . *. *....*.... ....:.... a ..
. . ..
- 1341 17fi
- 29 -
complex-forming acid. For conjugation with proteins,
also suitable are substituents having, for example, the
structure C6H4,N2, C6H4NHCOCH2, C6H4NHCS, or C6H40CH2C0.
Conjugation of the complex-forming acid with
dextrans and dextrins also takes place in accordance
with conventional methods, e.g. by activation of the
polysaccharides with cyanogen bromide and subsequent
reaction with amino groups of the complex-forming acid.
When using complex compounds which contain
radioisotopes, they can be prepared according to the
methods described in "Radiotracers for Medical Applica-
tions", vol. 1, CRC-Press, Boca Raton, Florida.
All starting materials used in the mentioned
conventional reaction are known or conventionally
preparable from known starting materials.
The pharmaceutical agents of this invention
are likewise prepared conventionally by suspending or
dissolving the complex compounds of this invention --
optionally while combining them with the additives
customary in galenic pharmacy -- in an aqueous medium
and then optionally sterilizing the suspension or
solution. Suitable additives are, for example,
physiologically acceptable buffers (such as, for ex-
ample, tromethamine), small amounts of complexing
agents (such as, for example, diethylenetriaminepenta-
acid acid) or, if required, electrolytes, e.g. sodium
chloride or, if needed, antioxidants, such as, for
example, ascorbic acid.
If suspensions or solutions of the agents of
this invention in water or physiological saline solution
are desirable for enteral administration or other pur-
poses, then they are mixed with one or several of the
auxiliary agents customary in galenic pharmacy (for
example, methylcellulose, lactose, mannitol) and/or
tensides (for example lecithins, and those sold under the
trademarks "Tween", "Myrj") and/or flavoring materials) to
improve taste (e. g. ethereal oils).
_;
.._.~..,..a.,'~~~!Y!0.::-.~.::~~~.: ~..~NIGn~S:v,.... ...... ..
' ' 1341 176
- 30 -
In principle, it is also possible to prepare
the pharmaceutical agents of this invention even without
isolating the complex salts. In any event, special
care must be directed toward effecting chelate forma-
tion in such a way that the salts and salt solutions
according to the invention are practically devoid of
uncomplexed, toxically active metal ions.
This can be ensured, for example, with the aid
of dye indicators, such as xylenol orange, by control
titrations during the manufacturing process. Therefore,
the invention also relates to processes for the produc-
tion of the complex compounds and their salts. Purifica-
tion of the isolated complex salt remains as a final
safety measure.
The pharmaceutical agents of this invention
preferably contain 1 umol to 1 mol per liter of the
complex salt and are normally administered in doses
amounting to 0.001 - 5 mmol/kg. They are intended for
entral and parenteral administration.
The agents of this invention fulfill the
variegated requirements for suitability as contrast
media for nuclear spin tomography. Thus, they are
excellently suited for improving the information content
of the image obtained with the aid of the nuclear spin
tomograph upon oral or parenteral administration, by
increasing the signal intensity. Furthermore, they
exhibit the high efficacy necessary to introduce into
the body a minimum amount of burdening foreign substances,
and they show the good compatibility necessary for main-
taining the noninvasive character of the examinations.
The good water solubility of the agents of
this invention makes it possible to prepare highly
concentrated solutions, thus maintaining the volume
load on the circulation within tolerable limits and
compensating for dilution by body fluids. Furthermore,
1341 1 76
- 31 -
the agents of the present invention not only exhibit
high stability in vitro, but also a surprisingly high
stability in vivo, so that a release or exchange of the
ions -- toxic per se -- which are not bound in a co-
y valent fashion in the complexes takes place only extreme-
ly gradually within the time period during which the
novel contrast media are again completely eliminated.
In general, the agents of this invention are
dosed, for use as NMR diagnostics, in quantities of
0.001 - 5 mmol/kg, preferably 0.005 - 0.5 mmol/kg.
Details of usage are discussed, fox example, in
H.J. Weinmann et al., Am. J. of Roentgenology 142 . 619
(1984), e.g., analogously to Gd-DTPA.
Extremely low doses (below 1 mg/kg) of organ-
specific NMR diagnostics are .usable,: for example, for the
detection of tumors and of cardiac infarctions. Fur-
thermore, the complex compounds of this invention can
be utilized advantageously as shift reagents.
On account of their favorable radioactive
properties and the good stability of the complex com-
pounds contained therein, the agents of this invention
are also suitable as radiodiagnostic media. Details of
their use and dosage are described, for example, in
"Radiotracers for Medical Applications", CRC-Press, Boca
Raton, Florida.
Another imaging method with radioisotopes is
positron emission tomography, utilizing positron-emitting
isotopes, such as, for example, 43Sc, 44Sc, 52Fe, 55Co
and 68Ga. (Heiss, W.D., Phelps, M.E., "Positron Emission
Tomography of Brain", Springer Publishers, Berlin, Heidelberg,
New York, 1983.)
1341 1 76
- 32 -
The compounds of this invention can also be
used in radioimmunotherapy. This procedure differs from
the corresponding diagnostics only by the amount and
type of radioactive isotope employed. The objective
herein is destruction of tumor cells by high-energy
shortwave radiation with as short a range as possible.
The specificity of the antibody employed is herein of
decisive importance since unspecifically localized anti-
body conjugates lead to destruction of healthy. tissue.
The antibody or the antibody fragment of the
antibody metal complex of this invention serves for
transporting the complex,in an immune-specific way for
the respective antigen, to the target organ where the
metal ion selected on account of its cytocidal proper-
ties can emit radiation causing lethal damage to the
cells. Suitable S-emitting ions are, for example,
46Sc~ 47Sc, 48Sc, ~2Ga and ~3Ga. Suitable a-emitting
ions exhibiting low.~half-life values are, for example,
211Bi~ 212Bi~ 213Bi and 214Bi,- wherein 212Bi is
preferred.
In the in vivo administration of the therapeutic
agents of this invention, these agents can be given
together with a suitable excipient, e.g. serum or
physiological sodium chloride solution and together
with another protein, such as, for example, human
serum albumin. The dose in this connection is dependent
on the type of cellular disorder, the metal ion used,
and the type of imaging method.
The therapeutic media of this invention are
administered parenterally, preferably intravenously.
See, e.g., R.W. Kozak et al, Trends in Biotechnology
(TIBTEC), October 1986, 262.
- 33 - 1341 1 76
The agents of this invention are excellently
suited as X-ray contrast media; in this connection, it
should be emphasized, in particualr, that their use does
not bring about any indications of anaphylaxis-type
reactions in biochemical-pharmacological tests. They
are especially valuable for digital subtraction techniques
on account of their favorable absorption properties in
regions of higher tube voltages.
In general, the agents of this invention are
used, when administered as X-ray contrast media, in
doses analogous to, for example, meglumine diatrizoate
in amounts of 0.1 - 5 mmol/kg, preferably 0.25 - 1 mmol/kg.
Details of usage of X-ray contrast media are
discussed, for example, in Barke, "Roentgenkontrastmittel"
[X-Ray Contrast Media], G. Thieme, Leipzig(1970),and
P. Thurn, E. Btlcheler, "Einfuehrung in die Roentgen-
diagnostik" [Introduction to X-Ray Diagnostics],
G. Thieme, Stuttgart, New York(1977).
The agents according to the invention are also
20. suitable -- since their acoustic impedance is higher
than that of body fluids and tissues -- as contrast media
for ultrasonic diagnostics, especially in the form of
suspensions. They are generally used in doses amounting
to 0.1 - 5 mmol/kg, preferably 0.25 - 1 mmol/kg.
Details of the use-of ultrasonic diagnostica
are disclosed, for example, in T.B. Tyler et al.,
Ultrasonic Imaging 3.323 (1981), J.I. Haft, "Clinical
Echocardiography", Futura, Mount Kisco, New York 1978,
and G. Stefan, "Echokardiographie" G. Thieme, Stuttgart/
New York, 1981.
1341 176
- 34 -
In summation, novel complex-forming compounds,
metal complexes, and metal complex salts are provided,
opening up new possibilities in diagnostic and
therapeutic medicine. This development appears to be
valuable, above all, in connection with the evolution of
novel imaging methods in medical diagnostics.
In the foregoing and in the following examples, all
temperatures are set forth uncorrected in degrees
Celsius and unless otherwise indicated, all parts and
percentages are by weight.
.4
1341 176
- 35 -
The synthesis of starting materials will be
described below by way of example, beginning with
a cyclization reaction:
(a) 1-Benzyl-4,7,10-tris(p-tolylsulfonyl)-
1,4,7,10-tetraazacyclododecane
At 100° C under agitation, 145 g of N,N-bis[2,2'-
(p-tolylsulfonyloxy)]ethanebenzylamine, dissolved in
900 ml of dimethylformamide is added dropwise within
3 hours to a solution of. 164.6 g o.f N,N' ,N' '-tris (p-tolyl-
sulfonyl)diethylenetriamine-N,N " -disodium salt in
2.16 1 of dimethylformamide. Then, under agitation at
80° C, one liter of water is added dropwise, and the
mixture is further stirred for 18 hours at room tempera-
ture, whereafter it is cooled to 0° C and the precip-
itate is suctioned off, washed with a small amount of
ice-cold ethanol and dried at 15 torr and 60° C,
yielding 175 g of the title compound.
Alternative Route 1
An analogous method for preparing tetraazacyclo-
dodecane derivatives is found in M. Hediger and T.A.
Kaden, Helv. Chim. Acta 66 . 861 (1983).
At 80-85° C, 30.94 g of N,N',N " -tris(p-tolyl-
sulfonyl)diethylenetriamine-N,N " -disodium salt and
28.12 g of N-bis(2-methanesulfonyloxyethyl)triphenyl-
methylamine are stirred with 530 ml of dimethylformamide
for 20 hours, then cooled off and stirred into a solu-
tion of 30 g of potassium carbonate in 5 1 of ice water.
The precipitate is suctioned off, the filter cake is
washed with 0.5 1 of water, and dried at 20oC under vacuum at
150 torr. For purification, the product is dissolved
in 230 ml of chloroform and 5 ml of triethylamine,
filtered, concentrated to 200 ml under vacuum, and
1341 1 7fi
- 36 -
the solution is combined under boiling heat with
250 ml of ethyl acetate. The mixture is allowed to
cool off overnight and the thus-precipitated crystals
are suctioned off, yielding 22.18 g of 1,4,7-
tris(p-tolylsulfonyl)-10-triphenylmethyl-1,4,7,10-
tetraazacyclododecane, mp 185-188 C (decomposition).
In order to split off the trityl blocking
group, 31.4 g of the tritosyl-trityl derivative
pr-epared in this way is stirred in a mixture of
100 ml of glacial acetic acid, 75 ml of water, and 300 ml
of dioxane for one hour at 80 C. Then the mixture is
exhaustively concentrated~under vacuum at 60,C, diluted
with 300 ml of ice water and combined with 40 ml of
11N sodium hydroxide solution (pH above 12). This
mixture is shaken with 300 ml of chloroform, the phases
are separated, the aqueous phase is extracted twice with
respectively 100 ml of chloroform, and the combined
~,t, chloroform phases are dried over sodium sulfate and
evaporated under vacuum. The frothy residue is
treated with 300 ml of diethyl ether, thus bringing about.
crystallization. The mixture is suctioned off, the
crystals~are dried under vacuum at 60 C and 150 torr,
and the yield is 21 g of 1,4,7-tris(p-tolylsulfonyl)-
1,4,7,10-tetraazacyclododecane, mp 202-203 C.
The thus-obtained tritosyl compound (21 g)
is dissolved in 200 ml of dimethylformamide, the
solution is combined in succession with 13.71 g of
anhydrous potassium carbonate, 4.95 g of sodium iodide,
and 7.92 g of benzyl bromide, and agitated for.5 hours
at 100 C, then cooled to 20 C, and the mixture is
stirred into 4 1 of ice water, suctioned off, and
the residue dissolved in 2 1 of dichloromethane. The
solution is extracted with 100 ml of water, dried
over sodium sulfate and evaporated under vacuum.
' 1341 1 76
- 37 -
The residue is dissolved under boiling heat in
500 ml of acetonitrile, allowed to crystallize over-
night, suctioned off, and the crystals are dried at
50° C and 150 torr, yielding 16.20 g of 1-benzyl-
4,7,10-tris(p-tolylsulfonyl)-1,4,7,10-tetraaza-
cyclododecane, mp 217-219° C.
(b) N-Benzyl-1,4,7,10-tetraazacyclododecane
150 g of 1-benzyl-4,7,10-tris(p-tolylsulfonyl)-
1,4,7,10-tetraazacyclododecane is heated with 900 ml of
HBr/acetic acid (40$ strength) and 125 g of phenol for
16 hours to 50° C. After cooling to 20° C, the mixture
is diluted with one liter of ether, cooled to -5° C,
and the thus-precipitated crystals are suctioned off.
In order to isolate the free base, the product is dis-
solved in 500 ml of 4N sodium hydroxide solution,
saturated with potassium carbonate, and repeatedly
ii!
extracted with chloroform, dried over magnesium sulfate,
and evaporated under vacuum. Yield: 39 g of the title
compound as a light-yellow, viscous oil. A sample
was characterized as the trihydrochloride: mp 210° C
(under decomposition).
Alternative Route 2
A solution of 11.2 g of 1,4,7,10-tetraazacyclo
dodecane in 900 ml of tetrahydrofuran is combined at
-20° C with 58 ml of triethylamine and, under agita
tion, a solution of 16.2 ml o,f benzoyl chloride in
280 ml of tetrahydrofuran is added dropwise thereto
within 3 hours. During this step, the room
temperature rises to slightly above -10° C.
The mixture is then agitated for 16 hours at 0-10° C,
the precipitate is filtered off, and the solution is
evaporated under vacuum. The residue is chromato-
graphed on 1 kg of silica gel and eluted with a
' - 1341 1 7~
- 38 -
solution of dioxane-water-ammonia (8:1:1). The fractions
uniform in accordance with TLC are combined, evaporated,
dissolved in dichloromethane, and filtered to eliminate
a slight turbidity, and the solution is evaporated,
thus obtaining 19.60 g of 1,4,7-tribenzoyl-1,4,7,10-
tetraazacyclododecane, mp 120-125 C.
11.5 g of the thus-obtained tribenzoate is
stirred in 150 ml of dimethylformamide with 8.3 g of
anhydrous potassium carbonate, 3.0 g of sodium iodide,
and 7.2 ml of benzyl bromide for 18 hours at 100 C.
The mxiture is then filtered, the solution evaporated
under vacuum, the residue stirred twice with respectively
50 ml of hexane, and decanted. The hexane phases are
discarded. For purification, the product is dissolved
in dichloromethane and chromatographed with dichloro-
methane-methanol (37:3) over 0.5 kg of silica gel,
thus obtaining 10.2 g of 1,4,7-tribenzoyl-10-benzyl-
1,4,7,10-tetraazacyclododecane, mp 105-109 C.
In order to split off the benzoyl groups, this
product (2.87 g) is dissolved in 290 ml of tetrahydro-
furan, combined with 11.2 g of potassium tert-butylate,
and heated under reflux for 48 hours. The mixture is
filtered, evaporated under vacuum, the residue combined
under ice cooling with 100 ml of water and extracted
three times with respectively 50 ml of dichloromethane.
The combined dichloromethane phases are shaken with
10 ml of water, dried over sodium sulfate, and evaporated
under vacuum. The initially oily residue crystallizes
very gradually and is triturated with 20 ml of hexane.
After suctioning off and drying, 1.15 g of N-benzyl-
1,4,7,10-tetraazacyclododecane is obtained, mp 75-78 C.
1341 1 7~
- 39 -
(c) 1-Benzyl-4,7,10-tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane
At 0° C, a solution of 131.8 g of N-benzyl-
1,4,7,10-tetraazacyclododecane in 1.5 1 of dichloro-
methane is combined in succession with 200 g of
triethylamine and, within 2 hours, with 260 g of
bromoacetic acid ethyl ester. The mixture is stirred
for 16 hours at room temperature, shaken with 5$
strength sodium carbonate solution and brine, dried
over magnesium sulfate, and evaporated under vacuum.
The residue.is dissolved in 200 ml of chloroform and
filtered over 2 kg of silica gel, eluting with one liter
of chloroform-methanol (95:5). Yield: 210 g of the
title compound as a viscous oil.
(d) N,N',N " -Tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane
____________________________________
100 g of 1-benzyl-4,7,10-tris(ethoxycarbonyl-
methyl)-1,4,7,10-tetraazacyclododecane is dissolved
in 0..5 1 of acetic acid and 0.5 1 of ethyl acetate,
combined with 5 g of palladium on carbon (10~), and
shaken under hydrogen for 5 hours. The mixture is
removed from the catalyst by filtration, concentrated
under vacuum, the residue is dissolved in one liter
of chloroform, shaken with 100 ml of saturated soda
solution and 100 ml of brine, dried, and evaporated
under vacuum. The residue is purified by bulb tube
distillation at 10 3 torr and 120° C, yielding
N,N',N " -tris(ethoxycarbonylmethyl)-1,4,7,10-tetra-
azacyclododecane as a viscous, light-yellow oil.
Yield: 65 g.
IR (Film): 3400, 2935, 2878, 1738/cm.
1341 1 ~6
- 40 -
Example 1
Gadolinium(III) Complex of 1,4,7,10-Tetraazacyclo-
dodecane-N,N',N " -triacetic Acid
40.25 g (100 millimoles) of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
is dissolved in 0.5 1 of ethanol, combined with 100 ml
of 3N sodium hydroxide solution, and stirred at 20° C
for 5 hours. The mixture is concentrated to 70 ml under
vacuum, combined with 300 ml of water, and 2N hydro-
chloric acid is added dropwise thereto up to a pH of 6.
Then the mixture is combined with 33.44 g (100 mmol)
of gadolinium acetate and stirred for 3 hours at 60° C.
The solution is then first passed over an anion ex-
changer "Amberlite"~'LRA 410 and then the aqueous eluate
is passed over a ca~ion exchanger "Amberlite" IRC 50.
The mixture is eluted with water and the eluate evap-
orated under vacuum. After drying of the residue, 35.04 g
(70$ of theory) of the title compound is obtained as a
colorless powder.
Anal~rsis: C14H23GdN406 (600.61)
C 33.59 H 4.63 Gd 31.41 N 11.19 (calc.)
33.31 4.59 31.18 11.28 (found)
1341 1 76
- 41 -
Example 2
Gadolinium(III) Complex of N-(2,3-Dihydroxy-N-methyl-
propylcarbamoylmethyl)-1,4,7,10-tetraazacyclo-
dodecane-N',N " ,N "'-triacetic Acid
55 g of N-(2,3-dihydroxy-N-methylpropyl-
carbamoylmethyl)-N',N " ,N "'-tris(ethoxycarbonyl-
methyl)-1,4,7,10-tetraazacyclododecane is dissolved
inØ5 1 of ethanol, combined with 96 ml of 3N sodium
hydroxide solution, and stirred at 20° C for 3 hours,
then concentrated under vacuum, combined with 300 ml
of water and adjusted to pH 6 with 2N hydrochloric
acid. To this solution is added 31.94 g of gadolinium
acetate and the mixture is stirred for 18 hours at 50° C,
then passed over an anion exchanger "Amberlite"
IRA 410, and subsequently the aqueous eluate is passed
over a cation exchanger "Amberlite" IRC 50. The
wj eluate is evaporated under vacuum and dried, thus
obtaining 47.14 g (73$ of theory) of the title
compound as a colorless powder.
Analysis: C20H34GdN509 (645.77)
C '37.20 H 5.31 Gd 24.35 N 10.85 (calc.)
37.52 5.19 24.09 10.87 (found)
The starting material for preparing the title
compound according to Example 2 is obtained as follows:
(a) N,N',N " -Tris(ethoxycarbonylmethyl)-1,4,7,10-
tetraazacyclododecane-N " '-acetic Acid
20 g of N,N',N " -tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane is dissolved in 300 ml
of dichloromethane, combined with 10.40 g of triethyl-
amine, and then at 0° C a solution of 4.40 g of
chloroacetic acid in 100 ml of dichloromethane
.
1341 1 76
- 42 -
is added dropwise thereto and the mixture agitated
at room temperature for 20 hours. For working-up
purposes, the mixture is divided between dich.lbro-
methane and phosphate buffer, pH 6, dried over
magnesium sulfate, and evaporated under vacuum,
yielding 23 g of the desired compound as a viscous
oil.
(b) N-(2,3-Dihydroxy-N-methylpropylcarbamoylmethyl)-
N',N " ,N "'-tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane
At 0° C, 10.5 g of triethylamine and then
14 g of chloroformic acid isobutyl ester
are added dropwise to a solution of 48.86 g (100 mmol)
of N,N',N " -tris(ethoxycarbonylmethyl)-1,4,7,10-
tetraazacyclododecane-N " '-acetic acid in 500 ml of
dichloromethane. The mixture is stirred for one hour at
0° C and then a solution of 10.52 g of N-methylamino-
2,3-propanediol in 100 ml of chloroform is added dropwise
thereto and the mixture is stirred at room temperature
for 2 hours. Subsequently the mixture is shaken with
sodium bicarboante solution and brine, dried over
magnesium sulfate, and evaporated under vacuum. For
purification, the chloroform solution of the residue
is filtered over 500 g of silica gel, yielding 55 g of
the title compound.
r ,
1341 1 7~
- 43 -
Example 3
Gadolinium(III) Complex of N-(N-Ethylcarbamoylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N " ,N " '-triacetic
Acid
24 g of N-(N-ethylcarbamoylmethyl)-
N',N " ,N " '-tris(ethoxycarbonylmethyl)-1,4,7,10-
tetraazacyclododecane is dissolved in 250 ml of ethanol,
combined with 47 ml of 3N sodium hydroxide solution,
and stirred for 3 hours.at 20° C, then concentrated under
vacuum, combined with 150 ml of water, and adjusted to
pH 6 with 2N hydrochloric acid. The mixture is combined
with 15.55 g of gadolinium acetate and stirred at 60° C
for 5 hours. The solution is then purified by way of
ion exchangers as described in the preceding examples,
thus obtaining 20.39 g of the title compound as a
colorless powder.
Analysis: C18H30GdN507 (585.72)
C 36.91 H 5.16 Gd 26.85 N 5.16 (calc.)
36.98 5.28 26.58 5.07 (found)
Preparation of the starting material:
g (51.2 mmol) of N,N',N " -tris(ethoxy-
carbonylmethyl)-1,4,7,10-tetraazacyclododecane-N " '-
acetic acid (see Example 2a) is dissolved in 200 ml
of dichloromethane, combined at 0° C with 5.40 g of
25 triethylamine, and subsequently with 7 g of chloroformic
acid isobutyl ester. The mixture is stirred for one
hour at 0° C and then a solution of 2.31 g of ethyl-
amine in 20 ml of dichloromethane is added dropwise
thereto. The mixture is stirred for 2 hours at room
temperature, shaken with saturated sodium bicarbonate
solution and brine, dried over magnesium sulfate, and
r
1341 176
- 44 -
evaporated to dryness under vacuum. For purification,
the dichloromethane solution of the residue is
filtered over 200 g of silica gel, thus obtaining
24 g of N- (N-ethylcarbamoylmethyl) -N' ,N" ,N" '-
tris(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclo-
dodecane.
Example 4
Gadolinium(III) Complex of N-Acetyl-1,4,7,10-tetra-
azacyclododecane-N',N " ,N " '-triacetic Acid
4.30 g of N,N',N " -tris(ethoxycarbonyl-
methyl)-1,4,7,10-tetraazacyclododecane is dissolved in
100 mlof:dichloromethane, combined with 10 ml of
pyridine, 100 mg of 4-dimethyaminopyridine, and
2.50 g of acetyl chloride, stirred at room temperature
for 5 hours, combined with 1 ml of ethanol, and evap-
orated under vacuum. The residue is stirred at room
temperature for 5 hours with 40 ml of 1N sodium
hydroxide solution, diluted with 100 ml of water,
and a pH is set of 6 with 2N hydrochloric acid. Then
3.34 g of gadolinium acetate is added to the reaction
mixture, and the latter is stirred at 60° C for
5 hours and the solution is subjected to purification
with ion exchangers (as described in the other examples),
thus obtaining 4.23 g of the title compound as a
colorless powder.
Analysis: C16H25GdN407 (542.65)
C 35.41 H 4.64 Gd 28.98 N 10.32 (calc.)
35.63 4.51 28.73 10.52 (found)
141 1 ~~
- 45 -
Example 5
Gadolinium(III) Complex of N-Ethyl-1,4,7,10-tetra-
azacyclododecane-N',N " ,N " '-triacetic Acid
4.30 g of N,N',N " -tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane is dissolved in 100 ml
of dichloromethane, combined with 2.10 g of triethyl-
amine and 3.12 g of iodoethane and, after 2 hours, the
mixture is repeatedly extracted with water, dried over
magnesium sulfate, and evaporated under vacuum. The
residue is stirred for 6 hours with 100 ml of 1N sodium
hydroxide solution, then adjusted to pH 6 with 2N
hydrochloric acid, and agitated for 16 hours with
3.34 g of gadolinium acetate at 60° C. The resultant
solution is subjected to purification with ion exchangers,
thus obtaining 3.70 g of the title compound as a color-
less powder.
Analysis: C16H27GdN406 (528.66)
C 36.35 H 5.15 Gd 29.74 N 10.60 (calc.)
36.15 5.32 29.70 10.41 (found)
Example 6
Gadolinium(III) Complex of N-(2,3-Dihydroxy-1-propyl)-
1,4,7,10-tetraazacyclododecane-N',N " ,N " '-
triacetic Acid
4.30 g of N,N',N','-tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane is dissolved in 100 ml
of dichloromethane, combined with 4.20 g of triethyl-
amine and 2.21 g of 3-chloro-1,2-propanediol, and
stirred at room temperature for 16 hours. The mix-
ture is shaken with water and evaporated under vacuum.
The residue is stirred for 6 hours with 100 ml of 1N
sodium hydroxide solution, adjusted to pH 6 with 2N
hydrochloric acid, and agitated for 16 hours with
1341 17fi
- 46 -
3.34 g of gadolinium acetate at 50° C. The thus-
obtained solution is subjected to ion exchanger
purification, yielding 3.62 g of the title compound
as a colorless powder.
Analysis: C17H29GdN408 (574.69)
C 35.53 H 5.09 Gd 27.36 N 9.75 (calc.)
35.68 5.19 27.03 9.68 (found)
Example 7
Gadolinium(III) Complex of N-(2-Aminoethyl)-1,4,7,10-
tetraazacyclododecane-N',N " ,N " '-triacetic Acid
2.10 g of triethylamine and 1.22 g of
N-(2-chloroethyl)acetamide are added to a solution
of 4.30 g of N,N',N " -tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane in 100 ml of dichloro-
methane. The mixture is stirred at room temperature
for 18 hours, shaken with water, and evaporated under vacuum.
The residue is atirred at 60 °. C 'for= 8 .hours :with 50 .ml
of 1N sodium hydroxide solution, adjusted to pH 6 with
2N hydrochloric acid, and stirred for 16 hours with
3.34 g of gadolinium acetate at 50° C. The thus-formed
solution is subjected to ion exchanger purification,
yielding 3.21 g of the title compound as a colorless
powder.
Analysis: C16H28GdN506 (543.68)
C 35.35 H 5.19 Gd 28.92 N 12.88 (calc.)
35.17 5.45 28.68 12.81 (found)
1 r
1341 1 7fi
- 47 -
Example 8
Bis[Gadolinium(III)] Complex of 1,1'-(1,3-Propylene)-
bis(1,4,7,10-tetraazacyclododecane-4,7,10-triacetic
Acid
A solution of 8.60 g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
and 4.2 g of triethylamine in 200 ml of dichloro-
methane is combined with 2.02 g of 1,3-dibromopropane
and agitated for 20 hours at room temperature, shaken
with water and brine, and evaporated under vacuum. The
residue is fitlered with dichloromethane over 150 g of
silica gel and evaporated, thus obtaining a viscous
oil which is stirred with 60 ml of 1N sodium hydroxide
solution for 16 hours, then diluted with 100 ml of
water and adjusted to pH 6 with 2N hydrochloric acid.
After adding 6.68 g of gadolinium acetate, the mixture
is stirred for 16 hours at 50° C and the solution is
purified over anion and cation exchangers, thus obtain-
ing 6.56 g of the title compound as a colorless powder.
Analysis: C31H50Gd2N8012 (1041.28)
C 35.76 H 4.84 Gd 30.20 N 10.76 (calc.)
35.71 4.58 29.94 10.88 (found)
Exam lp a 9
Bis[Gadolinium(III)] Complex of Succinyl-bis(1,4,7,10-
tetraazacyclododecane-4,7,1.0-triacetic Acid)
A solution of 4.30 'g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
and 4.20 g of triethylamine in 100 ml of dichloromethane
is combined at 0° C dropwise with 1.705 g of succinic
acid dichloride, dissolved in 20 ml of dichloromethane,
and then the mixture is stirred for one hour at room
temperature, shaken with sodium bicarbonate solution
_ 48 _ '341 1 ~s
and brine, and evaporated under vacuum. The residue
is chromatographed on 100 g of silica gel with
dichloromethane/ethyl acetate (0-30~).
A viscous oil is obtained which is stirred
with 40 ml of 1N sodium hydroxide solution for 4.hours,
then diluted with water (100 ml), and adjusted to pH 6
with 2N hydrochloric acid. After adding 3.34 g of
gadolinium acetate, the aniXture is stirred for 16 hours
at 50° C and the solution purified by way of ion
exchangers, thus obtaining 3.90 g of the title compound
as a white powder.
Analysis: C32H48Gd2N8014 (1083.28)
C 35.48 H 4.47 Gd 29.03 N 10.34 (calc.)
35.31 4.18 28.81 10.57 (found)
Example 10
Tris(Gadolinium) Complex of N6-Carboxymethyl-N3,N9-
bis(4,7,10-tricarboxymethyl-1,4,7,10-tetraazacyclo-
dodecan-1-yl)carbonylmethyl-3,6,9-triazaundecanedioic
Acid
A suspension is prepared from 3.57 g of
DTPA bis-anhydride in 100 ml of water and combined
with 4.2 g of triethylamine and 8.61 g of N',N " ,N " '-
tris(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclo-
dodecane. The mixture is stirred at room temperature
for 18 hours, combined thereafter with 200 ml of
ethanol, and suctioned off from the precipitated solid
matter. The filter cake is stirred with 100 ml of 1N
sodium hydroxide solution for:6 hours, then adjusted
to pH 6 with 2N hydrochloric acid, 10.03 g of
gadolinium acetate is added, and the mixture is stirred
at 50° C for 18 hours. The solution is purified as
1341 1 ~s
- 49 -
usual by way of ion exchangers, thus obtaining 8.32 g of
the title compound as a colorless powder.
Analysis: C42H62Gd3N11020 (1512.77)
C 33.35 H 4.13 Gd 31.18 N 10.18 (calc.)
33.41 4.05 31.02 10.03 (found)
The preparation and isolation of complexing
compounds will be demonstrated with the aid of the
examples set forth below. The isolated complexing
compounds can then be converted into the complexes,
for example with various paramagnetic ions.
Example 11
N-(2-Hydroxyethyl)-1,4,7,10-tetraazacyclododecane-
N' , N " , N " ' -triacetic Acid
A solution of 6.46 g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
in 150 ml of dichloromethane is combined with 3.2 g of
triethylamine and 1.45 g of 2-chloroethanol. The mix-
ture is agitated for 4 hours at room temperature,
then shaken with sodium bicarbonate solution and brine,
dried over magnesium sulfate, and evaporated under
vacuum: The residue is stirred for 16 hours with
60 ml of 1N sodium hydroxide solution. By adding
5N hydrochloric acid, the pH is adjusted to 2.5.
The resultant suspension is poured on an ion ex-
changer ("'DOWER"'~'S0W-X4 in the H+-form) , eluted with
water and then with 0.5-molar NH3 solution, and
concentrated under vacuum. The title compound is
isolated by adding ethanol and suctioning off the
precipitate. Yield: 4.24 g of the title compound;
purity is tested by pH titration and elementary analysis.
1341 1 ~fi
- 50 -
Analysis: C16H30N407 (390.44)
C 49.22 H 7.75 N 14.35 (calc.)
49.48 7.83 14.09 (found)
Example 12
N-Methoxyacetyl-1,4,7,10-tetraazacyclododecane-
N' , N " , N " ' -triacetic Acid
A solution of 6.46 g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
in 150 ml of dichloromethane is combined with 3.2 g
of triethylamine and 1.79 g of methoxyacetic acid chloride.
After one hour, the mixture is shaken with soda solu-
tion and brine, dried over magnesium sulfate, and
evaporated under vacuum. The residue is stirred with
60 ml of 1 sodium hdyroxide solution for 5 hours at
room temperature, then acidified to pH 2 by adding
dilute hydrochloric acid, and the thus-obtained
suspension is purified on a cation exchanger ("DOWER"
50 W-X4); elution is carried out with water and 0.5-
molar NH3 solution. The eluate is concentrated and
the title compound is precipitated by adding ethanol.
After suctioning and drying, 4.51 g of the title
compound is obtained. Test for purity is done by
titration and elementary analysis.
Analysis: C17H30N408 (418.45)
C 48.80 H 7.23 N 13.39 (calc.)
48.98 7.41 13.18 (found)
~3~~ 1~s
- 51 -
Example 13
N-[N-(2-Hydroxyethyl)carbamoylmethyl]-1,4,7,10-
tetraazacyclododecane-N',N " ,N " '-triacetic Acid
A solution of 12.50 g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane-
N " '-acetic acid in 250 ml of dichloromethane is
combined at 0° c with 5.22 g of triethylamine and then
with 3.50 g of chloroformic acid isobutyl ester.
After one hour, 1.60 g of ethanolamine, dissolved in
50 ml of dichloromethane, is added dropwise, the
mixture is stirred at room temperature for 2 hours,
shaken with soda solution and brine, dried over
magnesium sulfate, and evaporated under vacuum. The
residue is chromatographed with chloroform/acetone
(10:1) on 200 g of silica gel, thus obtaining 11 g
of N-(2-hydroxyethyl)carbamoylmethyl-N',N " ,N " '-
tris(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclo-
dodecane.
This product is stirred with 100 ml of
1N sodium hdyroxide solution for 5 hours at room
temperature, then acidified with dilute hydrochloric
acid to pH 2.5, and the suspension is purified on a
cation exchanger ("DOWER" 50A-X4), elution being
carried out with water and then with 0.5-molar NH3
solution. The eluate is extensively concentrated and,
after addition of ethanol, the title compound is
crystallized and isolated by filtration. Yield.
7.2 g of the title compound, the purity of which
is examined by titration and elementary analysis.
Analysis: C18H33N508 (447.49)
C 48.31 H 7.43 N 15.65 (calc.)
48.20 7.48 15.49 (found)
13+1 17~
- 52 -
Example 14
Gadolinium Complex of N-(Morpholinocarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N'',N " '-triacetic
Acid
Analogously to Example 2, 55.77 g of
N-(morpholinocarbonylmethyl)-N',N " ,N " '-tris(ethoxy-
carbonylmethyl)-1,4,7,10-tetraazacyclododecane is
hydrolyzed with sodium hydroxide solution and complexed
with gadolinium acetate, thus obtaining 45.19 g
(72~ of theory) of the title compound as a white
powder.
The starting material for preparing the
title compound is obtained by proceeding in analogy
to Example 2b, but using morpholine in place of
N-methylamino-2,3-propanediol.
.,
Analysis: C20H32GdN508 (627.75)
''' C 38.27 H 5.14 Gd 25.04 N 11.16 (calc.)
38.02 5.09 24.83 11.35 (found)
Example 15
Gadolinium Complex of N-(Morpholinocarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N " ,N " '-
tris(2-methylacetic Acid)
Analogously to Example 2, 53.06 g of N-
(morpholinocarbonylmethyl)-N',N " ,N " '-tris(1-ethoxy-
carbonyl-1-ethyl)-1,4,7,10-tetraazacyclododecane is
hydrolyzed with sodium hydroxide solution and
complexed with gadolinium acetate, thus obtaining
52.20 g (78~ of theory) of the title compound as a
white powder.
1341 1 ~fi
- 53 -
Analysis: C23H38GdN508 (669.83)
C 41.24 H 5.72 Gd 23.48 N 10.46 (calc.)
41.35 5.65 23.33 10.62 (found)
Example 16
Gadolinium Complex of 1-Oxa-4,7,10-triazacyclo-
dodecane-N,N',N " -triacetic Acid
10.42.g of 1-oxa-4,7,10-triazacyclododecane-
N,N',N " -triacetic acid and 9.85 g of gadolinium
acetate are stirred with 50 ml of water at 95° C.
After about 5 minutes, a clear solution is formed
which is maintained for another hour at 95° C. After
cooling, the solution is stirred in succession with
respectively 30 ml of cation exchanger IR 120 and
anion exchanger IRA-410, filtered, and evaporated
under vacuum, thus obtaining 9.17 g (61~ of theory)
of the title compound as a white powder.
Analysis: C14H22GdN307 (501.59)
C 33.52 H 4.42 Gd 31.35 N 8.34 (calc.)
33.63 4.50 31.18 8.42 (found)
The starting material employed is obtained
as follows:
13.86 g of 1-oxatriazacyclododecane is dis-
solved in 200 ml of water, combined with 30.24 g of
chloroacetic acid in portions and simultaneously
with 9.6N potassium hydroxide solution so that the
pH value of the solution remains between 9.8 and 11.8.
Then the mixture is heated for 2 hours to 100° C, while
maintaining the pH value at 10.0 by further addition
of potassium hydroxide solution. After cooling to
20° C, the mixture is adjusted to pH 2 by adding
26.5 ml of 12N hydrochloric acid and poured on 1.6 1 of
- 54 - 1341 176
cation exchanger IR 120 and eluted with 4.8 1 of water.
This eluate is discarded. Elution is continued with
1.2 1 of 0.5N ammonia and the mixture evaporated under
vacuum, thus obtaining 24.1 g of 1-oxa-4,7,10-triaza-
cyclododecane-N,N',N " -triacetic acid (86.8 of
theory), mp 68-70° C.
Example 17
Bis(Gadolinium) Complex of 1,1'-(2-Hydroxy-1,3-
propylene)-bis(1,4,7,10-tetraazacyclododecane-
4,7,10-triacetic Acid)
A solution of 43.05 g of N,N',N " -tris-
(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane
in 450 ml of dimethylformamide is combined with
4.63 g of epichlorohydrin. After one hour, the mix-
ture is combined with 7.5 g of sodium iodide and
heated for 24 hours to 80° C, concentrated under
vacuum, and the residue divided between water and
chloroform. The chloroform phase is dried over
sodium sulfate and evaporated under vacuum. The
residue is chromatographed on 1 kg of silica gel
with dichloromethane.- 10~ acetone, thus obtaining
27.5 g of l,1'-(2-hydroxy-1,3-propylene)-bis-
(1,4,7,10-tetraazacyclododecanetriacetic acid
ethyl ester) as a viscous oil.
9.17 g of the thus-prepared ester is dis-
solved in 200 ml of ethanol and stirred with 30 ml
of 3N sodium hydroxide solution for 20 hours at
room temperature; then a pH of 6 is set with hydro-
chloric acid and the mixture stirred for 16 hours at
60° C with 6.68 g of gadolinium acetate. The solu-
tion is purified over anion and cation exchangers,
yielding 10.05 g of the title compound as a white
powder.
' ' 1341 176
- 55 -
Analysis: C31H50Gd2N8013 (1057.28)
C 35.22 H 4.77 Gd 29.75 N 10.60 (calc.)
35.03 4.89 29.49 10.41 (found)
Example 18
N-Methylglucamine Salt of the Manganese(II) Complex of
N-[N-(2-Hydroxyethyl)carbamoylmethyl]-1,4,7,10-tetra-
azacyclododecane-N',N " ,N " '-triacetic Acid
8. 95 g ( 20 mmol) of N- [N- ( 2-hydroxyethyl) -
carbamoylmethyl]-1,4,7,10-tetraazacyclododecane-
N',N " ,N " '-triacetic acid is suspended in 30 ml of
water and heated with 1.40 g (20 mmol) of manganese(II)
oxide to 100° C for 3 hours. Then the mixture is
combined with 3.90 g (20 mmol.) of N-methylglucamine,
heated for another 12 hours to 100° C, and the solution
is evaporated to dryness under vacuum, thus obtaining
e'; 13.8 g of the title compound as a pink powder, mp 140-143° C.
Analysis: C25H48MnN6013 (695.64)
C 43.17 H 6.96 Mn 7.90 N 12.08 (calc..)
43.44 7.16 7.69 12.01 (found)
Example 19
Dysprosium(III) Complex of N-(Morpholinocarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N " ,N " '-triacetic
Acid
Analogously to Example 2, 20 g of N-
(morpholinocarbonylmethyl)-N',N " ,N " '-tris(ethoxy-
carbonylmethyl)-1,4,7,10-tetraazacyclododecane is
hydrolyzed with sodium hydroxide solution and complexed
with dysprosium acetate, thus obtaining 16.3 g of the
title compound as a white powder.
141 1~6
- 56 -
Analysis: C20H32DyN508 (633.01)
C 37.95 H 5.10 Dy 25.67 N 11.06 (calc.)
37.71 4.92 25.81 11.32 (found)
Example 20
Preparation of Liposomes Loaded with Gadolinium
N-(Morpholinocarbonylmethyl)-1,4,7,10-tetraazacyclo-
dodecane-N',N " ,N " '-triacetic Acid
In accordance with the procedure described
in Proc. Natl. Acad. Sci. U.S.A. _75 . 4194, a lipid
mixture is made up from 75 mol-$ egg phosphatidylcholine
and 25 mol-g cholesterol as the dry substance. Of this
quantity, 500 mg is dissolved in 30 ml of diethyl ether
and, in an ultrasonic bath, combined dropwise with
3 ml of an aqueous 0.1-molar solution of the gadolinium
complex of N-(morpholinocarbonylmethyl)-1,4,7,10-
tetraaza-N',N " ,N " '-triacetic acid. The ultrasonic
treatment is continued for 10 minutes and the mixture
is concentrated under vacuum. The gelatin-like
residue is suspended in 0.125-molar sodium chloride
solution and at 0° C repeatedly centrifuged at 20,000 g
in order to separate unencapsulated gadolinium complex.
The suspension is then subjected to freeze-drying in
multivials. Administration takes place as a colloidal
dispersion in 0.9$ strength sodium chloride solution.
1341 176
- 57 -
Example 21
Preparation of a Solution of the Yttrium-90 Complex of
the Conjugate of 1,4,7,10-Tetraazacyclododecane-
N,N',N " ,N " '-tetraacetic Acid with Monoclonal Antibodies
A suspension of 4 mg of 1,4,7,10-tetraaza-
cyclododecane-N,N',N " ,N " '-tetraazacyclododecane-
N,N',N " ,N " '-tetraacetic acid in 1 ml of water is
combined with 2 mg of N-(3-dimethylaminopropyl)-N'-
ethylcarbodiimide hydrochloride and then with l mi of
a solution of 0.6 mg of monoclonal:. antibody (with
specificity against melanoma antigen) in 0.05-molar
sodium bicarbonate buffer (pH 7.8). The mixture is
stirred for 2 hours at room temperature and dialyzed
against a 0.3-molar sodium phosphate buffer. Then
1 ml of an Yttrium-90 solution in acetate buffer pH 6
is added (prepared according to Int. J. Appl. Radiat.
Isot., 36 . 803 [1985]) and the mixture is incubated
for 24 hours at room temperature. The solution ~~ passed
through a "Sephadex"'r"'G 25 column and the radioactive
protein fraction is filtered under sterile conditions and
dispensed into multivials. By lyophilization, a dry
preparation that can be stored is obtained.
Example 22
Gadolinium Complex of N-(Isopropoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N'',N " '-triacetic
Acid
At 0° C, 10.5 g of triethylamine is added
dropwi.se to a solution of 48.86 g (100 mmol) of
N,N',N " -tris(ethoxycarbonylmethyl)-1,4,7,10-tetra-
azacyclododecane-N " '-acetic acid in 500 ml of
dichloromethane, and then 14 g of
chloroformic acid isobutyl ester is added. The mix-
ture is stirred for one hour at 0° C and then
t~
' ' . 1341 17fi
- 58 -
6.61 g of isopropyl alcohol is added dropwise and the
mixture stirred for 4 hours at room temperature, shaken
with sodium bicarbonate and brine, and evaporated under
vacuum. For purification, the chloroform solution of
the residue is filtered over 500 g of silica gel, thus
obtaining 45.0 g of N,N',N " -tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N " '-acetic acid iso-
propyl ester as a light-yellow, viscous oil.
A solution is made up from 10.61 g (20 mmol)
of the thus-produced isopropyl ester in 150 ml of
ethanol and at 0° C is combined during the course of
5 hours with 60 ml of 1N sodium hydroxide solution.
The mixture is stirred for another hour at 0° C, then
adjusted to pH 6 with 2N hydrochloric acid, and ex-
tensively concentrated under vacuum. Then the mixture
is diluted with 200 ml of water, combined with 6.69 g
of gadolinium acetate, and heated for 16 hours to 50° C.
The solution is then subjected to an ion exchanger
purification, yielding 8.20 g of the title compound as
a colorless powder.
Analysis: C19H31GdN408 (600.73)
C 37.99 H 5.20 Gd 26.18 N 9.33 (calc.)
38.22 5.31 26.02 9.41 (found)
1341 176
- 59 -
Example 23
Indium-111 Complex of N-(Morpholinocarbonylmethyl)-
1,4,7,10-tetraazacyclododecane-N',N ",N " '-triacetic
Acid
The process is performed analogously to
Example 14, forming the complex compound with radio-
active lllindium chloride. In order to ascertain
whether the metal ions are completely bound as a chelate,
the solution of the title compound is examined by thin-
layer chromatography on silica gel plates in the
system methanol-water (2:1). Metal ions that have
not been chelated are recognized herein as a.radioactive
zone at the starting spot. If necessary, chelating
is completed by the further addition of N-(morpholino-
carbonylmethyl)-N',N " ,N " '-tris(ethoxycarbonylmethyl)-
1,4,7,10-tetraazacyclododecane and subsequent ester
cleavage.
In the same way, the gadolinium-153 complex
of N-(morpholinocarbonylmethyl)-1,4,7,10-tetraaza-
cyclododecane-N',N " ,N " '-triacetic acid is obtained.
1341176
- 60 -
The preceding examples can be repeated with similar
success by substituting the generically or specifically
described reactants and/or operating conditions of this
invention for those used in the preceding examples.
S From the foregoing description, one skilled in the
art can easily ascertain the essential characteristics
of this invention, and without departing from the spirit
and scope thereof, can make various changes and
modifications of the invention to adapt it to various
usages and conditions.
