CA2113245A1 - Agents for the diagnosis of vascular diseases - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention relates to metal complexes and me-tal complex conjugates of endothelines, endotheline de-rivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, iodinated endo-theline derivatives, endotheline partial sequences, endo-theline analogues, or endotheline antagonists, and means containing such compounds, their preparation as diagnostic agents, as well as processes for the manufactu-ring of such compounds and agents.
In vivo applicable metal complexes and metal complex con-jugates of endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists as well as iodinated endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists are preferably used for the non-invasive imaging of vascular diseases.

Description

21~324~

This lnvention relates to the object characterized in the claims, i.e. metal complexes, metal complex conjugates of endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, iodinated endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, and compositions that contain these compounds, their use as agents for diagnosis, and the processes for preparing these compounds and compositions. Metal complexes, metal complex conjugates of endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, as well as iodinated endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists that are applicable in vivo are used to yield images of vascular diseases, preferably in a non-invasive way.

Atherosclerosis is a chronic, progressive disease of the blood vessels which has as yet been clinically diagnosable only at an advanced stage. Atherosclerotic vascular alterations are conventionally depicted by means of arteriography. A contrast medium is applied to the relevant vessel using a catheter. X-rays then detect the vascular areas that show a constriction. It is one of this method's disadvantages that it is only suited for viewing subsections of the vascular system. As arteriography is an invasive method, its application may cause complications e.g. pains, perforations of arteries, arrhythmia, cardiac or cerebral infarcts which in unfavourite circumstances may result in the patient's death.

ID99~N .DOC

2 2~132 !1~
Furthermore, method~ baeed on the u~e of ul~ra~onic wave~
and MR eomography are u8ed to diag~oae athero6clerosi~

All methodg currently a~plied hav~ the great di3advantage that thoy detece athe~o~clerotic ~a~cular changes ~rom the dimini~hed ~lood flow or ~ignificant alteration~ of th~ areery wall i~ the~e ~ection~ and are thu~ only capable of de~ecting advanced ~tages of atherogene~

Early detection of athero~clerosiff would be of great importance ~or monitoring the therapeutic e~fect of dlet~, calcium antagoni~t~, lipid and hypertenaion depre~ant~, for ~o~itoring re~tenosi~ after angioplastic surgery, for diagnosing coronary heart disea~e6, and fo~
detecting thrombotic deposi~s in the ve~els.

Non-invaeive methods o~ diagno~ing athero~clero~i~ ha~e b~en de w ribed before. Thu~, antibodies la~elled with radlol~otopes, or labelled low-den~ity lipoprotein~
(LDL), wQre introduced that bond to atherosclerotlc wall ~
~ectione (Leee et al. 1983, J. Nucl. Med. 24, 154-156; ~;
Kal$man et al. 1385, Circulation, 72, 300; Vi~golini et al. 1991, Eur. J. ~ucl. Med., 18, 944-947). Thee~ :
method~, however, have ma~o~ di~advantage~ ~.q, the antiyenic effect o~ the antibodieo on the ~y~tem and the long period of time (~e~eral day~) requlred to i~ola~e, refine, and label the LD~ obtai~ed ~rom the patient~
blood. Above all, these big moleculcs have a long half-li~e in the blood, which togcther with high background radlation make~ it difficult, if not impo~ le, to locate atherooclerotlc leeion~.

S~h et al. ~1990, Proc. Natl. Acad. Scl., B7, 1s36-l4so) ha~e aynt-he~ized partlal ~equencee of the LDL protein moiety (apo-B-~00) that ~tlll ~ond to the athero~clerotic plaque~ but have a con~iderably ~ho~ter half-llf~ ~n ~he ~ ' ., . - ~ .~ .. : . ............. .. : .

i~

~~` 3 2~ ~32~i`
blood and a~ improved e~g~a~-~oi~e ratio. A euccesa~ul in vlvo diagnoeis of atheroBclero~is, however. could no~ be e3tabli~hed with the~e apo-B-peptidee due to their lower afflnity to th~ plaque and/or lower denslty of the bondlng place~ ln ~he plaque.

It ie, therefore, an object of the invention to provide new compounde and compoeitions that are ~uited for a new, non-invaejive method of dlagnosie of, in particular, the early, non-~tenotic ~ascular dl~eases. Thie object 1~
accompliehed by the metal complexe~ and metal complex conjugate~ of endothelinen, endotheline derivativee, endotheline partial seguences, endotheline analogue~ or endoeheline antagoniet~, as well as iodinated endotheline derlvativee, endotheline partial eeguence~, endotheline analoguee, or endotheline antagonists according to the lnvention.

Endothellnee aro phyeiologically_acti~e peptidee that have both hormonic and neuroregulatory functions within the organi~m (MacCumber et al. 1989, Proc. Natl. Acad.
Sci., a6, 72~5-7289; Yanagieawa et al. 19~9, Trends Pharmacol. Sci., 10, 374-37~; LeMonier de Gouville et al., 19~9, ~ife Sci., 45, 1499-1513; Yanagisawa et al., 19~, Nature, 332, 411-415). Four dif~erent i50type9 have ae yet been ~ound in man ~Inoue et al,, 1989, Proc. Natl.
Acad. Scl., 86, 2863-2867). Sndotheline 1 ig a polypeptide coneietlng of the following eeque~ce of 21 ami~o acid~:
cye-eer-cye-eer-eor-leu-met-aep-lye-glu-cye-val-tyr-phe-cy~-hie-leu-a3p-ile-ile-trp ~Yanagleawa et al., 19~, Nature, 332, 411-41S). An inactive precureor of endotheline, the big endotheline, ie ~ormed by the vaecular endothelium. Endotheline, which I D~ I . DOI~

4 2 ~ 1 3 2 ~ 3 bond~ to ~pecific receptor~ of the smooth vascular muacles, i~ formed aSter the endothel~ne-converting enzyme (ECE) hae ~plit off a heptad~capeptide. There, it reA~lts in a Ca~+-mediated contraction of the smooth S mu~cle celle (Yanagisawa et al., l9B8, Nature, 332, 411-415; Takuwa et al. 1991, Contrib~ Nephrol., 90, 99-104).

The proliferatlon of smooth mùscle celle in the ve~sel wall due among other to growth factors (e.g. PDGF) i9 one of the early irrever~ible cha~gee that occur during at~erogenesi~ (Deemoulière and Gabbiani 1992, Cere~rovasc. Di~., 2, 63-71; Ro~ 1986, N. Engl. J. Med., 314, ~4~-5011. ~he~e proliferating cell~ alter their morpholosy and their phy~iological function (Deemoulière and Gabbiani 1992, Cerebrovasc. Dis., 2, 63-71). The in- ~`
vltro incubation of atheromatous human coronary arte~ies with 125I-endotheline 1 ~howe~ that increa~ed bonding of 125I-endotheline 1 occur~ in the tunica media a~d the vaea ~asora Bectione ~Da~hwood et al., 1991, J.
Cardio~asc. Pharmacol., 17, 45B-462). An increased uptake of 125I-endotheline 1 in the deendothellated aortic ~ectione wa~ found when 125I-endothcllne 1 was applied to rabbits who~e abdominal aorta had been deendotheliated ucing a balloon catheter. This indicate6 a higher den~ity of bonding places for endotheline 1 in the~e injured vaecular s~ctione (Rurata et al. 1992, J. Nucl. Med., 33, ;~
a45). The etudie~ indicate that the proliferating emoot~
muacle cell~ keep expre~slng the endotheline recepeor. ~-Endotheline 1 ha~ a ~trong vaeoconetricti~e effect on the ~mooth ~a~cular mu~culature (A. M. Doherty, 1992, Medlclnal ~hemi~try, 35, 1493-150~ here~ore, only relatively low concentration~ may be applied ~.~. to the organi~m. Higher concentra~ions may be applied of -~
endoCheline partial ~equencee, endotheline analoguee or endotheline anca~oniete, as they still bond to the tD-~-~ll.~C

2~32~

endotheline receptor but do not cause such a distinct contraction of the smooth muscle cells.

As endothelines are rapidly eliminated via the kidneys, S the disturbing background radiation due to endotheline uptake in other organs or tissues is extremely low.

It was found that radiolabelled endothelines, endotheline derivatives, endotheline partial sequences as well as appropriate endotheline antagonists and endotheline analogues accumulate to a surprisingly great extent in atherosclerotic vascular lesions, thereby reaching a concentration sufficient for visualization by a scintillation camera or any other appropriate apparatus used in nuclear medicine. Another surprising finding is that the substances used according to the invention reach this concentration in vivo so rapidly, and that the bond is so stable, that a concentration sufficient for diagnostics remains after the surplus of endotheline ~ ;
derivatives, antagonists, or other substances bonding to the receptor have been carried away and eliminated. It was still another surprise that the accumulation occurs preferably at the sections of the arterial wall that are to be diagnosed and varied in different kinds although endotheline is active on all vascular regions.

Moreover, the substances used according to the invention are particularly appropriate as they do not additionally and non-specifically accumulate in other tissues or organs, contrary to many other classes of substances and substancès tested. This is decisive for their suitability as agents for diagnosis.

The metal complexes, metal complex conjugates of endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline ID9338N.DDC

6 21~3~
antagonists, iodinated endotheline derivatives, endotheline partial ~equences, endotheline analogues, or endotheline antagonists according to the invention, and the solutions prepared from them, meet the requirements mentioned to a surprisingly great extent. They have both higher accumulation in pathological vascular areas and better contrast characteristics due to more favourable pharmacokinetics than the agents for diagnosis that have previously been described for detecting vascular diseases. The practical application of the new substances according to the invention is facilitated by their high chemical stability.

Complexes of compounds according to the invention of the general formula (I) ~-' ~ ~
E-L-(K)b (I) ~ , containing metal ions with the atomic numbers 21-32, 37-39, 42-51, and 57-83, are characterized, in that E is a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, or a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonist~ carrying free thiol groups and directly bindiny a metal ion;

L is a direct linkage or a Zl-R-Z2 residue, wherein R i~ a unbranched, branched, saturated or unsaturated Cl 20-alkyl group, optionally ~D93 98N . DOC

~ : ~2 ~ ~ ?~

7 21 13 2!15 interrupted by one or several oxygen and/or sulphur atoms and/or carbonyl, -NHCO-, -N(C1_6 alkyl)CO-, -NH- and -N(C1 6 alkyl) groups, and ~ ~9 optionally substituted with hydroxy and/or epoxy groups;

Z1 and Z2 are, independent of each other, an -O-, -S-, -(C=O)O-, -NH-(C=S)NH-, -(C=O)-, -(C=S)O-, -NH-, -NH-(C=O)-, or -NH-(C=S)- group, , ", ,~, "~ ~, or a residue of formula a (CH2)t - Z2 Z~--(CH2)5 {~ ( a ) ~ ~

wherein s and t are, independent of each other, the integers 0, 1, 2, or 3, :~;
ring B represents a phenyl or cyclohexyl group, and Z1 and Z2 have the abovementioned meaning, b represents the integers 0 or 1, K is a chelating agent residue of the general formula II A or II B
O O

R2 S- (CH2)n,- C- (TT);-C-- ( I I A ) .

:

ID931111N.DOC

21~32 O
R3 S (CH2)n~ C-NH
/R4 ( I I B ) ;~
R5 S ~ (CH2)n.--C ~ NH
O .

wherein R2, R3, and R5 are, independent of each other, a hydrogen atom, a (C1 6 alkyl)CO, (C6 8 aryl)CO, l-or (C7 9 arylalkyl)CO residue, optionally . ~:
substituted with a hydroxyl group, a C1 4 ~ ::
alkoxy, a carboxyl, or a sulphonic acid group, ..
and -:
' ' ' " '~ ' ' ' R4 represents a residue of either formula II C .
or II D
~ : :.:

--CH2 CH- ( I I C ) ~ ::
C=O :.. ' ::""' ,, --CH (CH2)2- ( 11 D ) C-O
.

wherein . 20 the carbon atoms labelled with an asterisk (*) are bound to the imino groups of formula II B, and wherein n' is an integer 1 or 2, . . ~

~D93911N,DOt!

9 2 ~ ~ 3 2 ~
i is any integer from 2 to 6, and ~.
TT represents a- and/or ~-amino acids linked together in the usual way through amide bonds;

as well as chelating agent residues derived from :.
dithiosemicarbazone derivatives of formula II E : :~

;:
R6 HN-N N-NH R6 ( I I E ) N =( )~ N
o SH HS

wherein :
R6 is a hydrogen atom or a Cl 6 alkyl group;

as well as chelating agent residues derived from bis(aminothiol) derivatives of formula II F

Ru r R~
, Rn~R,~ ~
--Rlo ~NHNH~-- R6--Rs ~ J ~ R~ (IIF ) R~ ~ ~ Rl7 R7 SH HS R~

wherein R7 to Rl8 represent, independent of each other, a : hydrogen atom, a Cl 10 alkyl chain and/or an L-linkage, while o, p, r are either integers 1 or 2; ..
.: .

ID93111~N.DOC

2 1 L 3 2 ~
a~ well as chelating agent residues derived from propylene aminoxime derivatives of formula II G

~CH2)m~

20--~ \~R2~
¦ (1I G ) ;
/ ~
R19 N N R24 ~ ;~
OH OH

wherein Rlg to R24 represent a hydrogen atom or a Cl 4 alkyl residue, either identical or different, : ~ :
and independent of each other, ~ :
m' is either integer 2 or 3;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II H ;

Y2 yNH X1 HNyY3 Az S S A4 T T

wherein Xl is a bond, a methylene group, or a CHY4 group, with one of groups Yl, Y2, Y3 or Y4 representing an L-linkage and the others hydrogen atoms or optionally an oxygen atom, ~D93BIIN.DOC

11 2~32~
T is a hydrogen atom, an alkaline metal ion, a ~:
Cl 6 acyl group, a benzoyl group, a hydroxyacetyl group, an acetamido methyl group, a p-methoxy benzyl group, an ethoxy ethyl group, or any other suitable SH protective group, Al, A2, A3 and A4 are hydrogen atoms or Cl 6 alkyl groups, either identical or different, and independent of each other other;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II J ;

R27 ~/
R25----R2s R26 'I H 1` R26 ( ll J ) ~ A A

wherein R27 represents a hydrogen atom, or a Cl 6 alkyl residue optionally substituted with one or two hydroxyl grcups, R25 and R26 are a hydrogen atom each, or an oxygen atom together ,\ , A is a hydroxyl or mercapto group, Y is a hydrogen atom, a carboxy or sulphonyl : residue, and Z is a carbon atom or a nitrogen atom;

ID91 B~N . DOC

~~~ ` 12 2~ ~32~
as well as chelating agent residues derived from amino polycarboxylic acids of either formula II K
or II L
CH2CO- CH2X CH2X CH2X ~, N- (CH2-CH2-N)n--CH2--CH2--(N~CH2~CH2)m N ( I I K ) ~ ~
CH2X CH2X : ;:
~ `
U Rl CH2X
N- (CH2)k--CH--(CH2)1 N
(CH2)o ~cH2)a ~ ( I I L ) N ((CH2)0~l~J)q wherein n and m are either integer 0, 1, 2, 3, or 4, with n plus m not exceeding 4, a i5 an integer 2, 3, 4, or 5 k is an integer 1, 2, 3, 4, or 5, 1 is an integer 0, 1, 2, 3, 4, or 5, and IS q i8 an integer 0, 1, or 2, : U represents a hydrogen atom, or a C1 6 alkyl group optionally substituted with one or several hydroxy groups and containing an L-linkage, each residue X represents hydrogen atoms, COOH
groups, ester groups, or amide groups with 1 to 6 carbon atoms in the alkyl residue, independent `
of each other, Rl is an L-linkage or a hydrogen atom;

SD9JJI~N.DOC

~ ` 13 21 L32~

as well as chelating agent residues of formula II
M, Cp(aa)Cp- (II M) wherein Cp is a protected cysteine and (aa) one of the naturally occurring amino acids;

as well as cysteine-rich amino acid sequences of the metalloid thionines -ser-cys-thr-cys-thr-ser-ser-cys-ala-, -ala-cys-lys-ala-cys-lys-cys-, -gly-cys-ser-lys-cys-ala-gln-gly-cys-val-, -cys-lys-gly-ala-ala-asp-lys-cys-thr-cys-cys-ala- ~-and analogous sequences in which serine has been replaced by threonine, glycine, or alanine;
as well as endotheline derivatives, endotheline partial sequences, endotheline analogues or .
endotheline antagonists that are labelled using radioactive iodine isotopes.

The metal ions contained in the complexes according to the invention have properties that facilitate their identification using physical methods. These -properties are, for example, paramagnetism, radioactivity including a-, ~-, and ~-radiation, and a large absorption cross section for X-rays and other radiation. This is true, in particular, of the transitional elements, the lanthanoids, and the main group elements of the 4th to 6th periods.

~D9398N.DOC

~` 21.L324~ :

Ions of isotopes of the following metals are particularly preferred due to such properties: Tc, Re, In, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Sa, Y, Gd, Tb, Dy, Ho, Er, and La. Moreover, some iodine isotopes have such ::
properties.

The complexes according to the invention of compounds of the general formula (I) E-L-(K)b (I) containing metal ions with the atomic numbers 21-32, 37-39, 42-51, and 57-83, -further contain residues E which derive from lS endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists. These residues E have the property to bond selectively to endotheline receptors.

The residues E preferably derive from endothelines.
Endotheline 1 i9 particularly preferred among the endothelines. It comprises the following sequence of amino acids (or parts thereof): ~;

cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-::
cys-his-leu-asp-ile-ile-trp.
. .:
The hydrophobic region of endotheline 1, hisl6-trp2l is essential for bonding to the receptor (Kimura et al., 1988, Biochem. Biophys. Res. Comm., 156, 1182-1186).

Furthermore, residues are preferred that derive from endotheline partial sequences.

~D9 3 3 liN . DOC

15 21~32'~ ~
Therefore, peptides that include the -his-leu-asp-ile-ile-trp-sequence of amino acids are particularly preferred among the endotheline partial sequences used according to the invention.

Furthermore, residues E are preferred that derive from endotheline analogues.

The particularly preferred endotheline analogues according to the invention comprise the following sequences of amino acids or parts thereof:
,~ :

-cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp- (endotheline 2) ,.
-cy~-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp- (endotheline 3) ,:, -cys-ser-ala-eer-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp- (ala-endotheline) '.' .
~ , -cys-ser-cys-asn-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe~
I

cys-his-leu-asp-ile-ile-trp- (VIC) -cys-ser-cys-lys-asp-met-thr-asp-lys-glu-cys-leu-aqn-phe-cys-his-gln-asp-val-ile-trp- (sarafotoxin S 6a) ID93011N.DOC

p`,.~ . !,,, `. ~,, ': ~ .' . . ~ ' , ~ ~ ' 16 2t 132~

I I
-ala-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-ala-his-leu-asp-ile-ile-trp- :
. .
-ala-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp--cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp-Furthermore, residues E are preferred that derive from endotheline antagonists.

Preferably used endotheline antagonists are cyclic ~.
pentapeptides e.g.

-D trp-D asp-pro-D val-leu- or -D glu-ala-allo D ile-leu-D trp-.
Furthermore, the complexes according to the invention of :
compounds of the general formula (I) ~

E-L-(K)b (I) ~.

containing metal ions with the atomic numbers 21-32, 37-39, 42-51, and 57-83, ~.
contain residues L that link the complexing agent :
residues K, which themselves bind the respective metal ions, with the residues E derived from endothelines, endotheline derivatives, endotheline partial se~uences, endotheline analogues or endotheline antagonists.

: In preferred complexes according to the invention, residue L is an unbranched, branched, cyclic, aliphatic, ~:

ID93al;N .DOC

~` 22 2~32-1~
containing metal ions, are further such complexes in which b takes the value 0 and L represents a bond.

The metal ions are bound to free thiol groups that are present in the residues E derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists.

For example, preferred metal ions are 99mTc and l86Re.

Other preferred compounds according to the invention are endotheline derivatives, endotheline partial sequences, `
endotheline analogues or endotheline antagonists labelled with radioactive iodine isotopes. The iodine isotopes have radioactive properties, which makes them detectable by physical methods. Particularly preferred iodine isotopes are l3lI, l25I, or l23I.
,~
Another object of the present invention are new conjugates between the complexing agent residue K and `
residue E, derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline `~
analogues or endotheline antagonists that are linked with one another through residue L and formed according to the general formula (I) E-L-(K)b (I) wherein:
E is a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists,;

L is a direct linkage or a Zi-R-Z2 residue, wherein ID91111N.WC

23 2~32~ -R is a unbranched, branched, saturated or unsaturated C1 2 0-alkyl group, optionally -interrupted by one or several oxygen and/or sulphur atoms and/or carbonyl, -NHCO-, -N(Cl 6 alkyl)CO-, -NH- and -N(C1 6 alkyl) groups, and optionally substituted with hydroxy and/or epoxy groups;

Z1 and 22 are, independent of each other, an -O-, -S-, -(C=O)O-, -NH-(C=S)NH-, -(C=O)-, -(C=S)O-, -NH-, -NH-(C=O)-, or -NH-(C=S)- group, or a residue of formula a ~ (CH2)t Z2 Zl (CH2)s~ ( a ) '~
wherein : ~ :
s and t are, independent of each other, the integers 0, 1, 2, or 3, ring B represents a phenyl or cyclohexyl group, and : : .
Zl and Z2 have the abovementioned meaning, b represents the integers 0 or 1, ,:, .. .
~ is a chelating agent residue of the general formula II A or II B
O :~, Il 11 :
R2 S-(CH2)n--C-(TT)I-C-- ( I I A ) ~
` ~' :~, ID93311N.DOC

:-~ 24 21~ 3~ 5 R

R3 S - (CH2)n'--C - NH
~R4 ( I I B ) R5--S - (cH2)n~ C - NH
O ,, wherein R2, R3, and R5 are, independent of each other, a -hydrogen atom, a (Cl 6 alkyl)CO, (C6 8 aryl)CO, or (C7_9 arylalkyl)CO residue, optionally substituted ~ -with a hydroxyl group, a Cl 4 alkoxy, a carboxyl, or a sulphonic acid group, and R4 represents a residue of either formula II C or : ~:
II D .
,",.. .

--CH2- CH- ( I I C ) C=O ' :' ~ 15 --CH (CH2)2 ( 11 D ) C-O

wherein the carbon atoms labelled with an asterisk (*) ..
are bound to the imino groups of formula II B, and wherein n' i8 an integer 1 or 2, ,~ i i9 any integer from 2 to 6, and ID938BN.DOC

2 1 ~3 2L~
TT represents a- and/or p-amino acids linked together in the usual way through amide bonds;

as well as chelating agent residues derived from dithio semicarbazone derivatives of formula II E
` ,~

R~, HN-N N-NH R6 ( I I E ) N =( . )~ N ~ :
SH HS ~- :

wherein R6 is a hydrogen atom or a Cl 6 alkyl group; ::~

as well as chelating agent residues derived from .
bis(aminothiol) derivatives of formula II F
: :::
R~ r Ru l Rn~R~ ~ , ...
--R~ -I,NH NH~-- R~
R ~ I F ) ~ ~;

R, SH HS R,B
.: , wherein R7 to R18 represent, independent of each other, a hydrogen atom, a Cl 10 alkyl chain and/or an L-linkage, while o, p, r are either integers 1 or 2;

as well as chelating agent residues derived from propylene aminoxime derivatives of formula II G

ID93aaN .DOC

-26 21132~ -~CH2)m~ ;
R20 ~/ NH NH~R23 l (ll G ) OH OH

wherein `. - ~:
Rlg to R24 represent a hydrogen atom or a Cl_4 alkyl residue, either identical or different, and independent of each other, m~ is either integer 2 or 3; ::

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II H
Y~

Y2 yNH X1 HNyY3 T T

wherein X1 is a bond, a methylene group, or a CHY4 group, with one of groups Yl, Y2, Y3 or Y4 representing an L-linkage and the others hydrogen atoms or an oxygen atom, if any, T is a hydrogen atom, an alkaline metal ion, a C1 6 acyl group, a benzoyl group, a hydroxyacetyl group, an acetamido methyl group, a p-methoxy benzyl ID9331~!1.DOC
,~ .

` 2~3~
: 27 ~:
group, an ethoxy ethyl group, or any other suitable SH protective group, . , .
Al, A2, A3 and A4 are hydrogen atoms or Cl 6 alkyl groups, either identical or different, and ~:
independent of each other;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II J ~ .:

R27 / '. .' R25 ~ R25 . , .~ . .
R26 ~ H N~ R26 ( J ) ~.

~ A A

wherein R27 represents a hydrogen atom, or a Cl 6 alkyl re~idue optionally substituted with one or two hydroxyl groups, R25 and R26 are a hydrogen atom each, or an oxygen atom together A is a hydroxyl or mercapto group, Y is a hydrogen atom, a carboxy or sulphonyl residue, and Z is a carbon atom or a nitrogen atom;
as well as chelating agent residues derived from amino ; polycarboxylic acids of either formula II K or II L
:

ID93311N.DO~ ~ ~
.

~ 28 2~324~ -CH2CO- CH2X CH2X CH2X '~
N (CH2-CH2-N)n--CH2--CH2--(N~CH2~CH2)m--N ( I I K ) CH2X CH2X ','~
... ..

y R1 CH2X
N- (CH2)k CH--(CH2)1 IN ~ :
¦ (CH2)a ~CH2)a ~ ( I I L ) :
' J
~ ((CH2)o~~)q :

wherein n and m are either integer 0, 1, 2, 3, or 4, with n plu8 m not exceeding 4, ~:~
a i8 an integer 2, 3, 4, or 5 k is an integer 1, 2, 3, 4, or 5, l is an integer 0, 1, 2, 3, 4, or 5, and q is an integer 0, 1, or 2, U represents a hydrogen atom, or a Cl 6 alkyl group optionally substituted with one or several hydroxy groups and containing an L-linkage, each residue X represents hydrogen atoms, COOH
groups, ester groups, or amide groups with 1 to 6 carbon atoms in the alkyl residue, independent of each other, Rl i8 an L-linkage or a hydrogen atom;

: as well as chelating agent residues of formula II M, Cp(aa)Cp- (II M) wherein ,'~ , ' ID93 311N . DOC

29 2 1 1 3 2 ~
Cp is a protected cysteine and (aa) one of the naturally occurring amino acids;

as well as cysteine-rich amino acid sequences of the metalloid thionines -ser-cys-thr-cys-thr-ser-ser-cys-ala-, -ala-cys-lys-ala-cys-lys-cys-, -gly-cys-ser-lys-cys-ala-gln-gly-cys-val-, -cys-lys-gly-ala-ala-asp-lys-cys-thr-cys-cys-ala-and analogous sequences in which serine has been replaced by threonine, glycine, or alanine.

The residues E of the complexes according to the invention of compounds of the general formula (I) E-L-(K)b (I) preferably derive from endothelines.
Endotheline 1 is particularly preferred among`the endothelines. It comprises the following sequence of amino acids (or parts thereof):
" ~ ~

cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-I
cys-his-leu-asp-ile-ile-trp.

The hydrophobic region of endotheline 1, hisl6-trp2l is essential for bonding to the receptor (Kimura et al., 1988, Biochem. Biophys. Re~. Comm., 156, 1182-1186).

Furthermore, residues are preferred that derive from endotheline partial sequences.

~ :

~D939BN.DOC

; ~ 30 2~32~

Therefore, peptides that include the -his-leu-asp-ile-ile-trp-sequence of amino acids are particularly .
preferred among the endotheline partial sequences used according to the invention.

Furthermore, residues E are preferred that derive from endotheline analogues.

The particularly preferred endotheline analogues according to the invention comprise the following sequences of amino acids or parts thereof:
. ., -cys-ser-cys-ser-ser-trp-leu asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp- (endotheline 2) -cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp- (endotheline 3) -cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-I

cys-his-leu-asp-ile-ile-trp- (ala-endotheline) -cys-ser-cys-asn-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe-,~ ;
cys-his-leu-asp-ile-ile-trp- (VIC) ..~
I -- I
-cys-ser-cys-lys-asp-met-thr-asp-lys-glu-cys-leu-asn-phe-cys-his-gln-asp-val-ile-trp- (sarafotoxin S 6a) ID9338N.DOC

31 21 l3 24~ ~

: ' ~.--ala-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-ala-his-leu-asp-ile-ile-trp-S
-ala-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp- ~ --cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp-Furthermore, residues E are preferred that derive from ~-endotheline antagonists. ~ ;~

Preferably used endotheline antagonists are cyclic pentapeptides e.g.
.'::
-D trp-D asp-pro-D val-leu- or -D glu-ala-allo D ile-leu-D trp-.
~;
: :
The complexes according to the invention of compounds of the general formula (I) E-L-(K)b (I~

preferably contain residues L that are unbranched, branched, cyclic, aliphatic, aromatic, or arylaliphatic and have up to 20 carbon atoms.
Furthermore, preferred residues L stand for Zl-R-Z2, ~`
wherein are:
Zl and Z2~ independent of each other, a -(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)- group, and R is an unbranched mono- to decamethylene group ID939~;N. DOC

32 2 ~ 1 3 2 ~ ~
or for a residue of formula a ~ (CH2)t - Z2 Z1 (CH2)s~ ( a ) wherein :
g equals 1 and t equals 0, and ring B is phenylene and wherein are Z1 and Z2l independent of each other, a -NH-(C=S)-, -NH-(C=S)NH-, .-(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)-group.

Preferred complexing agent residues K of compoundsaccording to the invention of the general formula (I) E-L-(K)b (I) derive from 4-carboxyethylphenylglyoxal-bis-(N-methyl-thio-semicarbazone)-N-hydroxysuccinimide ester, 6-(4'-ieothiocyanatobenzyl)-3,3,9,9-tetramethyl-4,8-diaza-undecane-2,10-dion-dioxime, 2-methyl-2-~4-isothiocyana- ~ :
tobenzyl)-N,N'-propylene-bis-~alicylidenamine, 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bie-[5- :~
(eulpho)ealicylidenamine, N,N'-bis[2-mercaptopyridyl)-methyl]-2-methyl-2-(4-isothiocyanatobenzyl)-1,3-propanediamine, S-benzoylthioacetylglycylglycyl glycine, N,N'-bis(benzoylthioacetyl)-2,3-diaminopropionic acid, N,N'-bie(benzoylthioacetyl)-3,4-diaminobutyric acid, ; .:
N,N'-bis(benzoylthioacetyl)-4,5-diaminopentanoic acid, : :~
N,N'-1,2-ethylene-diyl-bis-(2-mercapto-1-carboxy- ~.
ethylamine), Cy8 (Acm)GlyCys(Acm)GlyGlyArgGlyAspSer, ethylenediaminotetraacetic acid, diethylenetriamino-pentaacetic acid, trans-1,2-cyclohexane diaminotetra-acetic acid, 1,4,7,10-tetraazacyclododecanetetraacetic ~ .
acid, 1,4,7-triazacyclononane~riacetic acid, 1,4,8,11- :
'~
, ~D91 lBN . DOC

33 2 1 ~ 3 2 ~
tetraazatetradecane tetraacetic acid, 1,5,9-triazacyclo-dodecanetriacetic acid, 1,4,7,10-tetraazacyclododecane-triacetic acid, and 3,6,9,15-tetraazabicyclo[9,3,15]-pentadeca-1(15),11,13-trien-triacetic acid. If desired, a part of the carboxylic acids may be present as esters and/or amides.

If at least a part of the carboxylic acid groups is to be in the form of amides, tertiary amides are preferred. The residues may be saturated, unsaturated, unbranched or branched-chain, or cyclic hydrocarbons with up to 5 C
- atoms which may be optionally substituted, with 1 to 3 hydroxy or Cl-C4 alkoxy groups. The following groups shall be named as examples: methyl, ethyl, 2-hydroxy-ethyl, 2-hydroxy-1-(hydroxymethyl)-ethyl, l-(hydroxy-methyl)-ethyl, propyl, isopropenyl, 2-hydroxypropyl, 3-hydroxypropyl, 2,3-dihydroxypropyl, butyl, isobutyl, isobutenyl, 2-hydroxybutyl, 3-hydroxybutyl, 2-, 3-, and 4-hydroxy-2-methylbutyl, 2- and 3-hydroxyisobutyl, 2,3,4-trihydroxybutyl, 1,2,4-trihydroxybutyl, pentyl, cyclo-pentyl, and 2-methoxyethyl group. The amide residue may also be a heterocyclic 5- or 6-membered ring formed with an enclosure of the amide nitrogen. The following rings shall be named as examples the pyrrolidinyl, piperidinyl, pyrazolidinyl, pyrazolinyl, piperazinyl, morpholinyl, imidazolidinyl, oxazolidinyl, thiazolidinyl ring.

The complexes of compounds according to the invention of the general formula (I) containing metal ions are prepared using a process known in the art, in which a radioactive metal ion in the form of its permetallate reacts with a compound of the general formula (I) E-L-(K)b (I) ~D93911N.DOC

~` 34 21~32~
in the known way, with a reducing agent and op~ionally an auxiliary ligand, being present.

Preferred metal ions are 99mTc or Re in the form of pertechnate or perrhenate.

The reaction is preferably carried out in a hydrous medium at room temperature. The Sh protective groups are cleaved in situ or according to the processes known to a person skilled in the art from literature, for example, using basic hydrolysis, reductive decomposition, etc.
(see, for example, "Protective Groups in Organic Synthesis", T. W. Greene, John Wiley and Sons i981).

The complexes of compounds according to the invention of the general formula (I) containing metal ions are further prepared by reacting a suitable salt or oxide of a suitable paramagnetic or radioactive cation in a way known to a person skilled in the art with a compound of the general formula (I) E-L-(K)b (I).

Among the preferred radioactive metal ions is, for ; ;~
example 111In, preferred metal ions having paramagnetic properties are the ions of Gd. ;~
.
The paramagnetic cations are incorporated in the chelating agent residues II K and II L as known from literature (see, for example, DE 34 01 052 and EP
430863), where the metal oxide or salt (e.g. nitrate, acetate, carbonate, chloride, or sulphate) of the desired metal is suspended or dissolved in polar solvents eOgO
water or hydrous alcohols, and reacted with the ap-propriate amount of complexing ligands. If desired, -existing acidic hydrogen atoms or acid groups may be . ' ' '' .

ID93911N.WC

^~ 35 21 l3 24~
substituted by cations of inorganlc and/or organic bases or amino acids.

Among the appropriate inorganic cations are, for example, the lithium ion, the potassium ion, the calcium ion and, in particular, the sodium ion. Appropriate cations of organic bases are, among others, ions of primary, secondary, or tertiary amines e.g. ethanolamine, diethanolamine, morpholine, glucamine, N,N-dimethyl glucamine and, in particular, N-methyl glucamine. Among the appropriate cations of amino acids are, for example, those of lysine, arginine, and ornithine, as well as amides of otherwise acidic or neutral amino acids.

The complexes according to the invention of compounds of the general formula (I) containing metal ions are further prepared by cleaving the disulphide bridges that are present in the endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or -endotheline antagonists in the way known in the art, or by generating or introducing free thiol groups that react with the radioactive metal ion in the form of a permetallate in the presence of a reducing agent and optionally an auxiliary ligand using suitable processes ~;
e.g. the Trauts process .
~:
Metal complexes of compounds of the general formula (I) on the condition that L represents a bound and b takes the value 0, are prepared in the ways known from litera-ture, for example, by reducing the disulphide bridges present in E' that stands for endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists with 2-mercapto-ethanol according to the method described in EP 0 271 806 or in Nucl.Med.Biol. 1~, 607-609, 1992, and by labelling them using technetium-99m in the presence of auxiliary ID933~N.DOC

~` 36 2~321~
ligands e.g. pyrophosphate, gluconate, or glucohept-onate and a reducing agent in a way known in the art, or by reacting E' with suitable heterobifunctional cross-linkers as, for example, N-succinimidyl-3-(2-pyridyldi-thio) propionate, that are capable of forming an amide linkage with a terminal amino group or, optionally, an amino group of a properly substituted side-chain in E', and that have, on the other hand, a sulphur group, optionally protected; then splitting off the protective sulphur group in a way known in the art and labelling it in a way known in the art using technetium-99m or Re, or by reacting E' with suitable derivational reagents known from literature, e.g. imino thiolane, and by labelling it then with technetium-99m or Re in a way known in the .::
art. ~
- ::
The iodinated endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline ;
antagonists can be prepared preferably with 131I, l25I, or 123I Using e.g. the chloramine-T process (Krohn et al., 1977, BBA 490, 49), the lactoperoxidase method (Kitamura et al., 1990, Biochem. Biophys. Res. Commun.
170, 497-503; Emori et al., 1990, Biochem. Biophys. Res.
Commun. 162, 217-223), the Bolton-Hunter method (Bolton and Hunter, 1973, Biochem. J., 133, 529-539), the iodogen method (Fraker and Speck, 1978, Biophys. Res. Commun., ~ ~
80, 849-857), or other known pr~cesses : ~ ::
.~
The compounds according to the invention of the general formula (I) are prepared in a way known in the art by reacting a functional group in E' with a functional group in the general formula (III) - ;

(K)b-L-H (III) wherein ID99a8N.DOC

37 2~32~-~
E', L, K, and b have the meanings specified above.

The compounds of formula (I) are prepared using a process known to a person skilled in the art by reacting a functional group in L, for example, with a terminal or amino group, or a side-chain correspondingly substituted in E'. K' is linked to E' covalently, preferably through an amine or thioamine linkage, where E' represents endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists, and K' represents chelating agents of the general formulae II A to II M. ~ `
., , ~.
If the chelating agents K' are linked through a carboxyl group in L, the latter is transformed according to the processes known to a person skilled in the art, for example, the carbodiimide process (Fieser, Reagents for Organic Synthesis 10, 142), or by means of a mixed or cyclic anhydride (Org. Prep. Proc. Int. 1975, l, 215), or an activated ester (Adv. Org. Chem. Part B, 472) and successive reaction with a nucleophile group in E~, preferably an amino group, with the formation of a covalent bond.

Isothiocyanate and a-halogenacetyl derived complexing agents or complexes under pH control are also reacted in ways known from literature in a hydrous environment with the desired amine-containing E~ representing endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists.

E' is prepared according to the processes described by Barany and Marrifield in The Peptides: Analysis, ~5 Synthesis, Biology. Academic Press, New York, 1980;

,-.,-=..0~

2 1 i 3 2 '~ ? J

Stewart and Young, Solid-phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Rockford, IL, 1984.

Chelating agents K' of the general formula II A are prepared as known from literature (see EP 0248506) by chloracetylating N-terminal amino groups of di-, tri-, tetra-, penta-, or hexapeptides and successive reaction of the resulting N-chloracetyl peptides with alkali salts of thiocarbonic acids. Another process for preparing chelating agents K' of the general formula II A as known from literature (see EP 0248506) consists in reacting ~
suitable activated (for example, NHS ester) and S- :;
acylated derivatives of thioacidic acid or 3-thiopropionic acid with di-, tri-, tetra-, penta-, or hexapeptides. The respective carbonic acids are activated by a process known to a person skilled in the art, for example, according to the carbodiimide process (Fieser, -Reagents for Organic Synthesis 10, 142), or using a mixed ;
or cyclic anhydride (Org. Prep. Proc. Int. 1975, l, 215) or an activated ester (Adv. Org. Chem. Part B, 472). ;

Chelating agents K' of the general formula II B are prepared as known from literature (see EP 0248506) by -~
chloroacetylating the free amino groups of 1,2-diaminopropionic acid or 1,3-diaminobutyric acid and successive reaction of the resulting N,N'-dichloroacetyl diaminocarbonic acids with alkali salts of thiocarbonic acids. Another process for preparing chelating agents K' of the general formula II B as known from literature (see EP 0248506) consists in reacting suitable activated (for example, NHS ester) and S-acylated derivatives of thioacidic acid or 3-thiopropionic acid with 1,2-diaminopropionic acid or 1,3-diaminobutyric acid.
'. :' The respective carbonic acids are activated by a process known to a person skilled in the art, for example, ID9391;N.WC

2 1 ~ 3 2 `` 39 according to the carbodiimide process (Fieser, Reagents for Organic Synthesis 10, 142), or using a mixed or cyclic anhydride (Org. Prep. Proc. Int. 1975, 7, 215) or an activated ester (Adv. Org. Chem. Part B, 472).
Chelating agents K' of the general formula II E are prepared as known from literature by reacting a substituted 1,2-dicarbonyl compound with a thiosemicarbacide as described in European Patent Application EP 0 306 168.

Chelating agents K' of the general formula II F are principally prepared by reductive aminations of substituted or non-substituted 1,2-diketo or 1,3-diketo compounds with substituted, unsubstituted, protected or ~
unprotected aminothiols as described in EP 279 417. ~`

Chelating agents K' of the general formula II G are prepared as known from literature by reacting 2-substituted 1,3-propane diamines with 2-chlorine-2-alkyl-3-nitrosoalkanes as described in the European Patent Applications EP 0417 870 and EP 0 502 594, or by reacting 2-substituted 1,3-propane diamines with the respective imines that are reduced to the respective amines in the way known in the art.

Chelating agents K' of the general formula II H are prepared as known from literature (see US 4,897,255) by chloracetylating the free amino groups of 1,2- or 1,3-diaminoalkanoic acid (see EP 0248506) and successive reaction of the resulting N,N'-dichloroacetyl diaminocarbonic acids with alkali salts of thiocarbonic acids. Another process for preparing chelating agents K' of the general formula II H as known from literature ~see US 4,897,255) consists in reacting suitable activated (for example, NHS ester) and S-acylated derivatives of ID99a8N.DOC

.

~ 4~ 2~ 324~
thioacidic acid or 3-thiopropionic acid with diaminopropionic acid or 1,3-diaminobutyric ~cid. The respective carbonic acids are activated by a process known to a person skilled in the art, for example, according to the carbodiimide process (Fieser, Reagents for Organic Synthesis 10, 142), or using a mixed or cyclic anhydride (Org. Prep. Proc. Int. 197S, 2, 215) or an activated ester (Adv. Org. Chem. Part B, 472). The separation of the SH protective groups is done after coupling to E' according to the processes known to a person skilled in the art from literature, for example, using basic hydrolysis, reductive decomposition, etc. (see, for example, "Protective Groups in Organic Synthesis", T. W. Greene, ;~
John Wiley and Sons 1981). -~
Chelating agents K' of the general formula II J are ;~
generally prepared as known from literature by reacting -2-substituted 1,3-propane diamines with benzaldehydes o-substituted with an additional carboxylic or sulphonic acid residue, and optionally successive reaction of the Schiff reagents thus formed with the respective amines and, possibly, separation of the existing protective groups; or by reacting substituted malonic acid ~ ;
halogenides optionally with a benzylamine o-substituted with an additional carboxylic or sulphonic acid residue, as described in the European Patent Applications EP 0 417 870, EP 0 502 594, and EP 0 502 595.

Chelating agents K' of the general formula II K are prepared as known from literature.

Chelating agents K' of the general formula II L are prepared according to the process known to a person skilled in the art, as, for example, described in the -European Patent Application EP 0 512 661.

ID9~a3-.DOC

41 X1~32~
Chelating agents K~ of the general formula II M are prepared according to the processes of solid-phase peptide synthesis known from literature (Barany and Marrifield, The Peptides: Analysis, Synthesis, Biology. Academic Press, New York, 1980; Stewart and Young, Solid-phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Rockford, IL, 1984). Cysteines are used with the desired S-protective group. The peptides of formula II M are separated from the resin in an N-protected form. The free carboxyterminal end is activated by a process known to a person skilled in the art, for example, according to the carbodiimide process (Fieser, Reagents for Organic Synthesis 10, 142), or using a mixed or cyclic anhydride (Org. Prep. Proc. Int. 1975, l, 215) or an activated ester (Adv. Org. Chem. Part B, 472).

Cysteine-rich amino acid sequences of metallothionines (see Patent Application WO 91/17173) are prepared according to the processes of solid-phase peptide synthesis known from literature (Barany and Marrifield, The Peptides: Analysis, Synthesis, Biology. Academic Press, New York, 1980; Stewart and Young, Solid-phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Rockford, IL, 1984). Cysteines are used in S-protected form. The cysteine-rich amino acid sequences are separated from the resin in an N-protected form. The free carboxyterminal end is activated by a process known to a person skilled in the art, for example, according to the carbodiimide method (Fieser, Reagents for Organic Synthesis 10, 142), or using a mixed or cyclic anhydride (Org. Prep. Proc.
Int. 1975, l, 215) or an activated ester (Adv. Org. Chem.
Part B, 472). The protective groups are removed after coupling to E' according to the processes known to a person skilled in the art from literature, for example, using basic hydrolysis, reductive decomposition, etc.
.

~D93~ DOC

42 2 1 ~ 3 ~
(see, for example, ~Protective Groups in Organic Synthesis", T. W. Greene, John Wiley and Sons 1981).

The present invention further provides agents for diagnosis characterized by the content of a compound complex of the general formula (I) containing metal ions with atomic numbers 21-31, 37-39, 42-51, and 57-83. These agents are suited for various diagnostic methods by choosing the appropriate metal ion.
'-If the agent according to the invention is meant for use in radiodiagnostics, the central ion of the complex salt must be radioactive. This applies in particular to the ions of elements having atomic numbers 27, 29, 30-32, 37-39, 42-51, 62, 64, 70, 75, and 77. Preferred isotopes ;
are, for example, 99mTc, 186Re, and 111In. Endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists may also be radiolabelled using iodine isotopes. 123I is, for example, a preferred isotope for this use.

If the agent according to the invention is meant for use in NMR diagnostics, the central ion of the complex salt must be paramagnetic. This applies, in particular, to the divalent and trivalent ions of elements having atomic numbers 2~-29, 42, 44, and 57-70. Suitable ions are, for example, the chromium(III), manganese(II), iron(II), cobalt(II), nickel(II), copper(II), praseodymium(III), neodymium(III), samarium(III), and ytterbium(III) ions.
The gadolinium(III), terbium(III), dysprosium(III), holmium(III), erbium(III), and iron(II) ions are particularly preferred due to their strong magnetic moment.

If the agent according to the invention is meant for use in radiod~iagnostics, the central ion must derive from an ID933BN.DOC

i` 43 2 1 1 3 2 ~ ~ ~

element having a higher atomic number to achieve a sufficient absorption of the X-rays. It has been found that agents for diagnosis are suited for this that `~
contain a physiologically acceptable complex salt with central ions from elements having atomic numbers between ;~
21-29, 42, 44, 57-83; among these are, for example, the lanthan(III) ion and the abovementioned ions of the lanthanoid æeries.
: .
If the agent according to the invention is meant for use in positron emission tomography, the central ion must be a positron-emitting isotope. This applies, in particular, to isotopes e.g. 43Sc, 44Sc, 52Fe, 55Co, 68Ga and Cu (Heiss, W. d.; Phelps M. E.; Positron Emission Tomography of Brain, Springer Verlag Berlin, Heidelberg, New York 1983).

Another object of the present invention are processes for preparing the agents for diagnosis according to the invention.

The radiopharmaceutic agents according to the invention are prepared in a way known in the art by dissolving or suspending the complexing agents according to the inven-tion and their conjugates - while optionally adding the additives common in galenics - in a hydrous medium and then lyophilizing or sterilizing the solution or suspension optionally. Suitable additives are, for example, physiologically safe buffers ( e.g. trometha-mine), auxiliary ligand additives ( e.g. sodium citrate or sodium tartrate), reductants ( e.g. tin(II) chloride), or - if need be - electrolytes e.g. sodium chloride, or - if need be - (one of) the auxiliary agent(s) commonly used in galenics ( e.g. lactose, methyl cellulose, mannitol) and/or tenside(s) (for example, lecithlnes, Tween~, Myrj~). The composition of ~D919BN.DOC '~
,~; . : .

44 21~32~
the additives used must permit the preparing of the compounds according to the invention.

When applied in vivo in nuclear medicine, the agents according to the invention are dosed at 1 x 10-5 to 5 x 104 nmol/kg body weight, preferably at quantities between 1 x 10-3 to 5 x 102 nmol/kg body weight. Assuming a medium body weight of 70 kg, the amount of radioactivity for diagnostic applications is between 0.05 and 50 mCi, preferably 5 to 30 mCi, per application. Normally, a solution of the agent according to the invention i5 applied as an intravenous, intra-arterial, or peritoneal -~
injection of 0.1 to S ml of the agent according to the invention. Intravenous application is preferred. Details of its handling and dosage are described, for example, in "Radiotracer~ for Medical Applications", CRC press, Boca Raton, Florida. The compounds according to the invention are used for radiodiagnostic and radiotherapeutic purposes in the form of their complexes with radioisotopes from elements having atomic numbers 27, 29, 30-32, 37-39, 42-51, 62, 64, 70, 75, and 77.

The radiopharmaceutic agents according to the invention meet the varied conditions for being used as radiopharmaceutic agents in radiodiagnostics and radiotherapy. They are excellently capable of accumulating in target tissues after i.v. application, thereby permitting a non-invasive diagnosis of said tissues. Water solubility of the radiopharmaceutic agents is ensured - if need be - as described above by auxiliary agents common in galenics.

Moreover, the radiopharmaceutic agents according to the invention show not only a high in-vitro stability, but also a surprisingly high in-vivo stability, so that the radionuclide bound in the complex is either not released ID9391~N.DOC

~ 45 21 1 3 2 '1 ~ -or replaced at all, or not to a clinically relevant extent.

~he pharmaceutic agents for NMR and radiodiagnostics according to the invention are also prepared in a known way by dissolving or suspending the complex compounds ac-cording to the invention in a hydrous medium - while optionally adding, the additives common in galenics - and then optionally sterilizing the solution or suspension.
Suitable ad;litives are, for example, physiologically safe buffers ( e.g. tromethamine), complexing agent additives ( e.g. diethylene triamine pentaacetic acid), or - if need be - electrolytes e.g. sodium chloride or - if need be - antioxidants e.g. ascorbic acid.
The pharmaceutic agents according to the invention used in NMR diagnostics contain preferably l~mol to 1 moI/l of complex salt and are normally applied at dosages of 0.001 to 5 mmol/kg. They are meant for enteral and parenteral application. The compound complexes according to the invention are used for NMR and radiodiagnostic purposes in the form of their complexes with ions of elements having atomic numbers 21-29, 42, 44, and 57-83.

The agents according to the invention meet the varied conditions required for their use as contrast media in nuclear spin tomography. After oral or parenteral application, they increase signal intensity and are thus excellently suited for improving the meaningfulness of an image obtained by nuclear spin tomography. Moreover, they are highly effective, which minimizes the amount of foreign matter the human body has to deal with, and well compatible to ensure the non-invasive nature of the examinations.
' ID9~98N.WC

-' 211 32~

Neutrallzation is done by inorsanic bases ( e.g~
hydroxides, carbonates or bicarbonates) of, for example, sodium, potassium, lithium, magnesium, or calcium and/or of organic bases e.g. prima~y, secondary, and tertiary amines like ethanol amine, morpholine, glucamine, N-methyl and N,N-dimethyl glucamine, as well as basic amino acids like lysine, arginine, and ornithine, and of amides ~-~
of originally neutral or acidic amino acids.

The agents according to the invention are excellently suited for use as x-ray contrast medium; it should be pointed out, in particular, that biochemical and pharmacological tests did not reveal any signs of ~ :
immediate allergy reactions as they are known from other contrast media. They are of particular value for digital subtraction techniques due to their favourable absorbing capabilities in higher tube voltage ranges.

The pharmaceutic agents according to the invention are further prepared in a way known in the art by dissolving the complexing agents according to the invention - while adding a reducing agent, preferably tin(II) salts chloride or tartrate, and, optionally the additives common in galenics - in a hydrous medium and then sterilizing them by filtration. Suitable additives are, for example, physiologically safe buffers ( e.g.
tromethamine), minor quantities of electrolytes ( e-g-sodium chloride), stabilizers l e-g- gluconate, phosphates, or phosphonates). The pharmaceutic agent is either present as a solution or in lyophilized form;
briefly before its application it is mixed either with a Tc-99m pertechnetate solution eluted from commercially available generators, or with a perrhenate solution.

A cold kit according to the invention is provided to prepare the radiopharmaceuticals. It contains a compound :
', :. :
;Ds3a8N.Dcc -~ 2~132~

according to the invention of the general formula (I), a reductant, and, optionally, one or more auxiliary ligands, either in solution, dry, or lyophilized. The cold kit, moreover, contains directions for use including directions for reacting the compounds according to the invention of general formula (I) with a permetallate of a radioactive metal ion, whereby a complex according to the invention is formed containing the compound of general formula (I) and the metal ion.
Furthermore, a cold kit is provided to prepare the radiopharmaceuticals that contains endothelines, endotheline derivatives, endotheline partial sequences, endothe~ine analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent capable of binding metal atoms and, optionally, a metal atom bonded to it. This latter metal atom may not be radioactive and can easily be replaced by a radioactive isotope.
Another object of the present invention is a hot kit containing endotheline~, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent with a radioactive iodine atom bonded to the latter.

Another object of the present invention is the use of the cold kit for preparing a radioactive formulation comprising a closeable vessel containing a predetermined quantity of endothelines, endotheline derivatives, i endotheline partial sequences, endotheline analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent capable of binding metal atoms, and containing a quantity of a reducing agent sufficient to label the compound with 99mTc.

~D933ilN~DOC

~': . t,. . ....

-- 21 ~ 32~ :

Another object of the invention is a method for imaging pathological vascular changes characterized in that a complex of a compound of general formula (I) containing metal ions of atomic numbers 21-32, 37-39, 42-51, and 57-83 is used as a contrast medium.
:~
The method according to the invention for imaging ;
pathological vascular changes is further characterized in that a radiolabelled endotheline is used as a contrast medium. The radiolabelled endotheline used in the method -~
according to the invention for imaging pathological vascular changes preferably contains a radioactive lodine isotope. l3lI, l2sI, and l23I are particularly preferred.
These iodinated endothelines are prepared in a generally known manner, preferably according to the chloramine-T
-~ocess, the lactoperoxidase proceSs the Bolton-Hunter or the iodogen process In one method of carrying out a radiodiagnostic examination, the radiopharmaceutic composition is applied to a patient at a dose of 0.1 to 30 mCi, preferably of 0.5 to 10 mCi per 70 kg of body weight, and the radiation emanating from the patient is recorded.
In the accompanying drawings:
Figures 1 and 2 illustrate the method according to the invention for imaging pathological vascular changes.

Fig. 1 shows a posterior planar recording of a WHHL
rabbit 5 h p.i. of l23I endotheline 1. -':
Fig. 2 shows a Sudan(III) dyeing and an autoradiograph of the aorta of a WHHL rabbit. The aorta was removed 5 h p.i. of l23I endotheline 1.

~D9391iN.DOC

49 2~324~
The object of the invention is described in more detail by the following examples.

Example 1 In-vivo and in-vitro accumulation of l23I endotheline 1 in WHHL rabbits.

Endotheline 1 was labelled with 123I using the chloramine-T method (Krohn et al. 1977, BBA 490, 49). 20 ~l endotheline 1 (2 ~g, equivalent to 0.8 nmol, in phosphate buffer, 0.25 mol/l, pH 7.4; SIGMA Co.) are added to 50 ~1 phosphate buffer (0.25 mol/l, pH 7.4), 100 ~l of 123I (15 ~l 123I, Medgenix Co., 74 MBq, equivalent to 2 mCi, brought to a total volume of 100 ~l by adding 0.01 mol/l of NaOH), and 100 ~l chloramine-T solution (35.5 mmol/l phosphate buffer, 0.25 mol/l, pH 7.4) for 2 mins at room temperature. 1000 ~l sodium disulphite ~olution (Na2S2O5; 6.3 mmol/l, 0.25 mol/1, pH 7.4) are added and briefly mixed to stop the reaction. 800 ~1 sodium iodide solution (13.3 mmol/l phosphate buffer, !~ "~ ;~
0.25 mol/l, pH 7.4) are pipetted into the initial charge to saturate the still vacant valencies (total charge quantity 2070 ~l). This reaction charge is gel filtrated through Sephadex G-10 (mobile buffer: phosphate buffered saline (7.4) 0.1 ~ BSA (w/v)). Labelling of endotheline was successful at 39 ~.

The five fractions of l23I endotheline 1 with the highest activity were collected (4.5 ml) and applied to the anaesthesized WHHL rabbit (Rompun/Ketavet 1:2) via an ear vein. Due to the missing or defective LDL receptor, WHHL
rabbits have a high LDL level in their blood and thus spontaneously show atherosclerotic vascular changes. The dose applied was equivalent to 0.2 mmol 123I endotheline 1 with an activity of 13.69 MBq (0.37 mCi), and a ID93 asN . DOC

21 ~ 32~

specific activity of 68.5 MBq/mmol. During the test period of 5 h after the application, static scintigraphs were made from various positions using a gamma camera (Elcint SP4 HR). The rabbit was killed 5 h aftex application, and an autoradiograph of the aorta and Sudan III dyeing were carried out. The aorta of the WHHL
rabbits could be imaged in vivo 4 h p.i. due to the labelling of endotheline with l23I (see Fig. 1). A
subsequent autoradiography revealed a complete labelling of the aorta wall and the atherosclerotic plaques (see Fig. 2). The enrichment factor between normal and atherosclerotic wall regions was between 8 and 12 depending on the formation of the plaques (Sudan III
dyeing).
~
Example 2 ~ -a) S-benzoylthioacetyl-gly-gly-gly-gly-asp-his-leu-asp-ile-ile-trp.
A solution of 50 mg S-benzoylthioacetyl-gly-gly-gly and 16 mg N-hydroxysuccinimide in absolute freshly distilled dimethyl formamide is cooled to -15C and added to 29 mg dicyclohexyl carbodiimide in absolute dimethyl formamide.
The reaction mixture is stirred for 2 hours at -5C, then for 2 hours at room temperature, and then cooled to -15C. N,N'-dicyclohexyl urea that settles down is filtered off. The filtrate i9 added to a solution of 1 mg gly-asp-his-leu-asp-ile-ile-trp in absolute dimethyl formamide and stirred for 20 hours at room temperature.
The reaction solution is concentrated to a minimum under vacuum. Dropping in diethyl ether results in a flocculent precipitate which is isolated and then purified using preparative HPLC (gradient: acetonitrile/phosphate buffer). After neutralizing the buffered solution, the ID933BU.DO~

~~~ 51 21~32~

organic solvent portion is blown off using N2, and the residue is freeze-dried.
Molecular weight: calc. 1301.4 det. 1301 (FAB-MS) b) 99mTc complex of S-benzoylthioacetyl-gly-gly-gly-gly-asp-his-leu-asp-ile-ile-trp.

A solution of 0.5 mg of S-benzoylthioacetyl-gly-gly-gly-gly-asp-his-leu-asp-ile-ile-trp in 300 ~1 phosphate buffer (Na2HP04, 0.1 mol/l, pH 9.5) is added to 50 ~1 of a 0.15 molar trisodium citrate dihydrate solution and 2.5 ~1 of a 0.2 molar tin(II) chloride dihydrate solution.
The reaction mixture is added to a pertechnetate solution (0.4-0.9 mCi) from a Mo-99/Tc-99m generator, incubated for 15 min at room temperature and then filtrated (0.2 filter). Labelling is analysed using HPLC: MERCK
nucleosil-column, 125 x 4 mm, 5 ~m; gradient from 100 % A
to 100 ~ B within 7.5 min. EIuent A: phosphate buffer tNa2HP04; 0.01 M; pH 2.0); eluent B:acetonitrile/
phosphate buffer (Na2HP04; 0.01 M; pH 2.0) 75:25 (V/V);
flow rate: 1.0 ml/min.

Example 3 a) N,N'-bis(S-benzoylthioacetyl)-3,4-diaminobutyryl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, A solution of 50 mg N,N~-bis(S-benzoylthioacetyl)-3,4-diaminobutyric acid and 15 mg N-hydroxysuccinimide in absolute freshly distilled dimethyl formamide i5 cooled to -15C and added to 28 mg dicyclohexyl carbodiimide in absolute dimethyl formamide. The reaction mixture is ID9331~1.DOC

` ` 2~32~

stirred for 2 hours at -5C, then for 2 hours at room temperature, and then cooled to -15C. N,N'-dicyclohexyl uxea that settles down is filtered off. The filtrate is added to a solution of 1 mg cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp (endotheline 1) in absolute dimethyl formamide and stirred for 20 hours at room temperature. The reaction solution is concentrated to a minimum under vacuum.
Dropping in diethyl ether results in a flocculent precipitate which is isolated and then purified using HPLC (gradient: acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.
Molecular weight: calc. 2948.5 ,;
det. 2949 (FAB-MS) b) 99mTc complex of ~ ~`
N,N'-bis(S-benzoylthioacetyl)-3,4-diaminobutyryl-.
cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, N,N'-bis~S-benzoylthioacetyl)-3-4-diaminobutyryl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp is labelled according to example 2b.
Example 4 a) Amide conjugate of 4-carboxyethylphenylglyoxal-bis-(N-methylthio semicarbazone)-N-hydroxy succinimide ester and I - I
cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe-I

ID93a8tl.WC

',',' 2 ~ 3 3 2 -~ ~J

cys-his-leu-asp-ile-ile-trp.

. .
A solutio~n of 1 mg 4-carboxyethylphenylglyoxal-bis-(N-methylthio semicarbazone)-N-hydroxy succinimide ester in 50 ~1 dioxane is added to a solution of 1 mg cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp (endotheline 2) in 100 ~1 phosphate buffered saline, pH 8.4, in a nitrogen atmosphere, and stirred for 15 hours at a temperature below 10C. The conjugate is purified using a preparative HPLC (gradient:
acetonitrile/phosphate buffer). After neutralizing the ~ ;
buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.
....
Molecular weight: calc. 2895.4 det. 2894 (FAB-MS) b) 99mTc complex of 3-[p-phenylglyoxal-di(N-methylthio semicarbazone)]-propionyl-cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys-I~ , val-tyr-phe-cys-his-leu-asp-ile-ile-trp.
3-[p-phenylglyoxal-di-(N-methylthio semicarbazone)]-propionyl-cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys- ~' val-tyr-phe-cys-his-leu-asp-ile-ile-trp is labelled according to example 2b.
Example 5 a) 3,6-Diaza-1,8-dimercapto-2,7-bis-(carbonyl-gly-his-leu-asp-ile-ile-trp) octane.

ID9~8N . I~OC

` 54 21i324~
256 mg (0.5 mmol) N,N~-1,2-ethylene diyl-bis-L-cysteine-di-(4-nitrophenyl) ester (manufactured according to EP 0 279 417) is added in portions in an argon atmosphere to a solution of 853 mg (1 mmol) NH2-gly-his-leu-asp-ile-ile-trp (manufactured in analogy to Barany and Marrifield, The Peptides: Analysis, Biology, Academic Press, New York, 1980; Stewart and Young, Solid-Phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Roc~ford, IL, 1984) and 304 mg (3 mmol) triethyl amine in 100 ml absolute dimethyl formamide. The mixture is stirred for 24 h at room temperature. When the reaction is finished, the mixture is filtrated, and the solvent is drawn off ~-under vacuum. To the remaining oil 50 ml diethyl formamide is added and evaporated three times. The residue is mixed up with 200 ml absolute diethyl ether.
The white solid that settles down is filtered off. It is ~;
recrystalliæed from dimethyl formamide/diethyl ether mixtures.
.
Yield: 278 mg (28.7 %), white powder.
Analysis: calculated on the anhydrous substance Calc.: C 55.77 H 6.86 N 15.90 O 18.16 S 3.31 Found: C 55.49 H 7.03 N 15.81 S 3.07 b) 99mTc complex of 3,6-diaza-1,8-dimercapto-2,7-bis-~carbonyl-gly-his-leu-asp-ile-ile-trp) octane.
A solution of 0.5 mg of the prepared 3,6-diaza-1,8-dimercapto-2,7-bis-(carbonyl-gly-his-leu-asp-ile-ile-trp) octane in 300 ~1 phosphate buffer (Na2HPO4, 0.5 mol/l, pH
7.0) is added to 50 ~l of a 0.15 molar trisodium citrate dihydrate solution and 2.5 ~1 of a 0.2 molar tin(II) chloride dihydrate solution. The reaction mixture is added to a pertechnetate solution (0.4-0.9 mCi) from a Mo-99/Tc-99m generator, incubated for 10 min at room temperature and then filtrated (0.2 ~ filter). Labelling ~D9331~N.NC

55 2 1 1 3 2 4 ~
is analysed using HPLC: MERCK nucleosil-column, 125 x 4 mm, 5 ~m; gradient from loO ~ A to 100 ~ B within 7.5 -min. Eluent A: phosphate buffer (Na2HP04); 0.01 M; pH
2.0) 50 : 50 (V/V); flow rate: 1.0 ml/min.
Example 6 a) {[(3,3,9,9-tetramethyl-4,8-diaza-undecyl-2,10-dion-dioxime?-6-yl]methylphen-4~-yl} aminothiocarbonyl-cys-,~, ~er-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp.

A solution of 1 mg 6-(4'-isothiocyanatobenzyl)-3,3,9,9-tetramethyl-4,8-diazaundecane-2,10-dion-dioxime in 50 ~1 tetrahydrofurane is mixed in a nitrogen atmosphere with a solution of 1 mg cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp (ala-endotheline) in 100 ~1 water and stirred overnight. The conjugate is purified using a preparative HPLC (gradient:
acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 2833.3 det. 2833 (FAB-MS) b) 99mTc complex of {[(3,3,9,9-tetramethyl-4,8-diaza-undecyl-2,10-dion-dioxime)-6-yl]methylphen-4'-yl}
aminothiocarbonyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp.

{[(3,3,9,9-tetramethyl-4,8-diaza-undecyl-2,10-dion-dioxime)-6-yl]methylphen-4'-yl} aminothiocarbonyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-ID93 311N . DOI:

` 56 2~ 132~
his-leu-asp-ile-ile-trp is labelled according to example 2b.

Example 7 ;~
a) N,N'-bis(S-benzoylthioacetyl)-4,5-diamino-1-oxo-..
pentyl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp. ;~

A solution of 50 mg N,N'-bis(S-benzoylthioacetyl)-4,5-diaminopentanoic acid and 15 mg N-hydroxy succinimide in absolute freshly distilled dimethyl formamide is cooled to -15C and added to 28 mg dicyclohexyl carbodiimide in ~ ;~
absolute dimethyl formamide. The reaction mixture is stirred for 2 hours at -5C, then for 2 hours at room ~`
temperature, and then cooled to -15C. N,N'-dicyclohexyl urea that settles down is filtered off. The filtrate is added to a solution of 1 mg cys-ser-cys-ser-ser-leu-met- ~
asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp - ~;
(endotheline 1) in absolute dimethyl formamide and stirred for 20 hours at room temperature. The reaction solution is concentrated to a minimum under vacuum.
Dropping in diethyl ether re ults in a flocculent precipitate which i9 isolated and then purified using preparative HPLC (gradient: acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 2962.5 det. 2963 (FAB-MS) ~D911RN.DOC

- ` 2~ ~32~

b) 99mTc complex of N,N~-bis(S-benzoylthioacetyl)-4,5-diamino-l-oxo-pentyl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp.

N,N'-bis(S-benzoylthioacetyl)-4,5-diamino-1-oxo-pentyl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp is labelled according to example 2b.

Example 8 a) {[2,6-diaza-1,7-di(2-hydroxyphenyl)-4-methyl-hept-4-yl]
-methyl-phen-4'-yl} aminothiocarbonyl-r cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp. `~

A solution of 1 mg 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'propylene-bis-salicylidenamine in 50 ~1 tetrahyd~rofurane is mixed in a nitrogen atmosphere with a solution of 1 mg cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp (endotheline 3) in 100 ~l water and stirred overnight. The conjugate is purified using a preparative HPLC (gradient:
acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic sol~ent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 3090.7 det. 3091 ~F~3-MS) b) 99mTc complex of {[2,6-diaza-1,7-di(2-hydroxyphenyl)-4-methyl-hept-4-yl]-methyl-phen-4'-yl} aminothiocarbonyl-cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp.
. .

ID93 38N . DOC
~,. .

- 21~2~ ~

{[2,6-diaza-1,7-di(2-hydroxyphenyl)-4-methyl-hept-4-yl]-methyl-phen-4'-yl~ aminothio-carbonyl-cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp is labelled according to example 2b.
Example 9 a) {[2,6-diaza-1,7-di(2-hydroxy-5-sulphophenyl)-4-methyl-hept-4-yl]-methylphen-4'-yl} aminothiocarbonyl-ala-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe- ;
ala-his-leu-asp-ile-ile-trp. ~-A fresh solution of 1 mg 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bis-[5-(sulpho)salicylidenamine3 in 50 ~1 water is mixed in a nitrogen atmosphere with a solution of 1 mg ala-ser-ala-ser-ser-ieu-met-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp in 100 ~l water and stirred overnight.
The conjugate is purified using a preparative HPLC
(gradient: acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.
Molecular weight: calc. 2959.4 det. 2959 (FAB-MS) b) 99mTc complex of ~[2,6-diaza-1,7-di(2-hydroxy-5-sulphophenyl)-4-methyl-hept-4-yl]-methylphen-4'-yl} aminothiocarbonyl-ala-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp.

{[2,6-diaza-1,7-di(2-hydroxy-5-sulphophenyl)-4-methyl-hept-4-yl]-methylphen-4~-yl} aminothiocarbonyl-ala-ser-: :

ID9338N~WC

. - ~ . - .. ; . - ~ ~ . ~. ~ . . . ,:: . :

59 2~32~
ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-ala-his-leu-asp-ile-ile-trp is labelled according to example 2b.

Example 10 a) N-[3,6,9-triaza-1-oxo-3,6,9-tris-(hydroxycarbonylmethyl)-9-ethoxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp.

403.4 mg (1 mmol) 3-ethoxycarbonylmethyl-6-[2-(2,6-dioxomorpholino)-ethyl]-3,6-diaza-octanedioic acid (DTPA-monoethyl ester monoanhydride) is added in portions to a solution of 853 mg (1 mmol) NH2-gly-his-leu-asp-ile-ile-trp (prepared in analogy to Barany and Marrifield, The Peptides: Analysis, Biology, Academic Preqs, New York, 1980; Stewart and Young, Solid-Phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Rockford, IL, 1984) and 506 mg (5 mmol) triethyl amine in 100 ml absolute dimethyl formamide. The mixture is stirred for 24 h at room temperature. When the reaction is finished, the mixture i8 filtrated, and the solvent is drawn off under vacuum.
To remaining oil 50 ml diethylformamide is added and evaporated three times. The residue is mixed up with 200 ml absolute diethyl ether. The white solid that settles down is filtered off. It is recrystallized from dimethyl formamide/diethyl ether mixtures.
Yield: 634 mg (50.4 %), white powder.

Analysis: calculated on the anhydrous substance Calc.: C 54.49 H 6.82 N 14,49 O 24.20 Found: C 54.23 H 7.03 N 14.34 b) Synthesis of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp. -.~., ~D9311EN.DOC

2 ~ .5 1.26 mg (1 mmol) of the prepared N-[3,6,9-triaza-1-oxo-3,6,9-tris-(hydroxycarbonyl-methyl)-9-ethoxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp (example lOa) is suspended in 100 ml water. A pH value of 12.5 is set by adding 10 molar, hydrous sodium hydroxide solution. The mixture is stirred for 5 h at room temperature, and a pH value of 2 is set by adding concentrated hydrochloric acid. The crude conjugate is filtered off and rewashed using a small amount of iced water and ice-cooled methanol. For purifying, it is taken up in little water at pH 7 and chromatographed on silica gel RP-18 (eluens: water/tetrahydrofurane, tetrahydrofurane: 0-50 ~). The fractions containing the conjugate are evaporated and the residue is taken up in a small amount of water at pH 4.5. The product is precipitated at pH 2, achieved by adding concentrated hydrochloric acid, and dried under reduced pressure.

Yield: 213 mg (17.3 %), white powder.

Analy~is: calculated on the anhydrous substance Calc.: C 53.78 H 6.65 N 14,82 0 24.75 Found: " C 53.49 H 6.91 N 14.57 Alternatively, N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp (example lOb) can also be prepared by reacting 853 mg (1 mmol) NH2-gly-his-leu-asp-ile-ile-trp (example lOa), dissolved in 100 ml water, at a pH of 9 in portions with 3.57 g (10 mmol) bis-(aminoethyl)-N,N,N',N",N"'-pentaacetic acid dianhydride. The mixture is stirred for 3 h at room temperature while permanently keeping the pH
value of the reaction medium at 9 by dropping in lN
hydrous sodium hydroxide solution. Then, a pH value of 2 is set by adding concentrated hydrochloric acid. The crude con~ugate is filtered off and rewashed using a ~D93311N.DOC

61 21 l32~
small amount of iced water and ice-cooled methanol. For purifying, it is taken up in a small amount of water at pH 7 and chromatographed on silica gel RP-18 (eluens:
water/tetrahydrofurane, tetrahydrofurane: 0-50 %). The fractions containing the conjugate are evaporated and the residue is taken up in a small amount of water at pH 4.5.
The product is precipitated at pH 2, achieved by adding concentrated hydrochloric acid, and dried under reduced pressure.
Yield: 317 mg (25.7 ~), white powder.

c ) 99mTc complex of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp A solution of 0.5 mg of the prepared N-~3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxy-carbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp (example lOb) in 300 ~l phosphate buffer (Na2HP04, 0.5 mol/l, pH 7.0) is added to 50 ~1 of a 0.15 molar trisodium citrate dihydrate solution and 2.5 ~l of a 0.2 molar tin(II) chloride dihydrate solution.
The reaction mixture is added to a pertechnetate solution (0.4-0.9 mCi) from a Mo-99/Tc-99m generator, incubated for 10 min at room temperature and then filtrated (0.2 filter). Labelling is analysed using HPLC: MERCK
nucleosil-coulmn 125 x 4 mm, 5 ~m; gradient from 100 ~ A
to 100 ~ B within 7.5 min. Eluent A: phosphate buffer -(Na2HP04); 0.01 M; pH 2.0) 50 : 50 (V/V); flow rate: 1.0 ml/min.

d) lllIn complex of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp ID9391~N.DOC

62 2~ ~3 2 A solution of 0.5 mg of the prepared N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxy-carbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp (example lOb) in 300 ~l phosphate buffer (Na2HPO4, 0.5 mol/l, pH 6.5) is incubated for 10 min at room temperature using 20 ~ 1InCl3 (3 MBq, NEN, Du Pont) and then filtrated (0.2 ~ filter). Labelling is analysed using HPLC: MERCK nucleosil-column 125 x 4 mm, 5 ~m; gradient from 100 % A to 100 ~ B within 7.5 min.
Eluent A: phosphate buffer (Na2HPO4); 0.01 M; pH 2.0) 50 : 50 (V/V); flow Fate: 1.0 ml/min.

e) Gd(III) complex of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp, sodium salt.
669 mg (2 mmol) gadolinium(III) acetate is added in portion at a pH of 6.5 to a solution of 2.46 g (2 mmol) of the prepared N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxy-carbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp (example lOb) in 100 ml water while keeping the pH ofthe reaction mixture between 6 and 6.5 by adding 10 N of hydrous sodium hydroxide solution. When the total amount of gadolinium has been added, the mixture is stirred for 4 h. After complexing has been finished, the product is set to a pH value of 7 by dropping in 1 N of hydrous hydrochloric acid solution and filtrated. The clear solution is freeze-dried. The residue is taken up in a small amount of water and chromatographed on silica gel RP-18 (eluens: water/tetrahydrofurane, tetrahydrofurane:
0-50 ~). The fractions containing the product are freed from tetrahydrofurane using a rotary evaporator; the residual solution is freeze-dried.

Yield: 1.13 mg (39.6 %), white powder.
Analysis: calculated the anhydrous substance ID9391~N.DOC

` ` 63 2~~~2~
Calc.: C 46.31 H 5.37 N 12.76 O 21.31 Gd Na 3.22 11.02 Found: C 46.09 H 5.63 N 12.49 Gd Na 3.51 10.83 Example 11 Gd(III) complex of 1-~2-hydroxy-3-[4-(gly-his-leu-asp-ile-ile-trp-thiouridyl)phenoxy] propyl} 1,4,7,10-tetraaza-4,7,10-tris-(carboxylatomethyl)-cyclododecane 708 mg (1 mmol) 1-[2-hydroxy-3-(4-isothiocyanato-phenoxy)-propyl]-1,4,7,10-tetraaza-4,7,10-tris-(carboxylatomethyl) cyclododecane, Gd complex (manufactured according to EP 0 485 054) is added in portions in an argon atmosphere to a solution of 853 mg (1 mmol) NH2-gly-his-leu-asp-ile-ile-trp (prepared in analogy to Barany and Marrifield, The Peptides: Analysis, Biology, Academic Press, New York, 1980; Stewart and Young, Solid-Phase Peptide Synthesis, 2nd ed., Pierce Chemical Co., Rockford, IL, 1984) and 304 mg (3 mmol) triethyl amine in 100 ml absolute dimethyl formamide. The mixture is stirred for 24 h at room temperature. When the reaction is finished, the mixture is filtrated, and the ~ ;
solvent is drawn off under vacuum. To the remaining oil 5Q ml diethyl formamide is added and evaporated three times. The residue is mixed up with 200 ml absolute diethyl ether. The white solid that settles down is ~;
filtered off. It i9 recrystallized from dimethylformamide/d;.ethyl ether mixtures.
~' ' ' '''~
Yield: 533 mg (34.0 %), white powder.
':
Analysis,~ calculated on the anhydrous substance Calc.: C 50.02 H 5.94 N 13.46 O 18.45 S 2.05 Gd 10.07 ID9331~N.DOC
. ' ' ',',~'~:! ` :, ' , :, '- :. :`,:: . .~ . . ` , ' ' ' .'.:, . . :

64 2t ~324~
Found: C 49.78 H 6.23 N 13.17 S 1.89 Gd 9.83 Example 12 a) cys(acm)-gly-cys(acm)-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr- ~-phe-cys-his-leu-asp-ile-ile-trp.
A solution of 50 mg Fmoc-cys(acm)-gly-cys(acm) and 15 mg N-hydroxy succinimide in absolute, freshly distilled dimethylformamide is cooled to -15C and added to 28 mg ~;
dicyclohexyl carbodiimide in absolute dimethylformamide.
The reaction mixture is stirred for 2 hours at -5C, then for 2 hours at room temperature, and then cooled to -15C. N,N'-dicyclohexyl urea that settles down is filtered off. The filtrate is added to a solution of 1 mg cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp (endotheline 1) in absolute dimethylformamide and stirred for 20 hours at room temperature. To split off the protective group, some piperidine is added to the reaction solution, stirred for 30 min, and subsequently concentrated to a minimum under vacuum. Dropping in diethyl ether results in a flocculent precipitate which is isolated by centrifugation and then purified using preparative HPLC (gradient:
acetonitrile/phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 2897.4 ¦ det. 2898 (FAB-MS) ID93 911N . DOC
.

~ ~3~ ~
b) 99mTc complex of cys(acm)-gly-cys(acm)-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp.

Cys(acm)-gly-cys(acm)-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp is labelled according to example 2b.

Example 13 a) Cyclo(trp-leu-val-pro-asp)-cys(acm)-gly-cys(acm). -A solution of 133.0 mg Cyclo(trp-leu-val-pro-asp) (prepared according to EP 0,436,189) and 41.3 mg hydroxybenzotriazole in 6 ml absolute, freshly distilled dimethylformamide is cooled to -15C and added to a solution of 51.7 mg 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in 8 ml absolute dimethyl ~-formamide. The reaction mixture is stirred for 2 hours at ~--5C, then for 2 hours at room temperature while slowly dropping in a solution of 134.0 mg cys(acm)-gly-cys(acm)-O-t-but in absolute dimethyl formamide. After stirring on for 7 h, the mixture is concentrated under vacuum to a minimum. Present protective groups are removed using trifluoroacetic acid, the peptide is precipitated by adding ether and then purified using preparative HPLC
(gradient: acetonitrile/ phosphate buffer). After neutralizing the buffered solution, the organic solvent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 1016.2 det. 1016 (FAB-MS) : .
~, ' ' .
. -,.:

ID9331~N.DOC

66 21 13~ ~ ~
b) 99mTc complex of cyclo(trp-leu-val-pro-asp)-cys(acm)-gly-cys(acm).

Cyclo(trp-leu-val-pro-asp)-cys(acm)-gly-cys(acm) is labelled'`according to example 2b.

Example 14 .
a) 4-mercaptobutyrimidyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp A solution of 500 ~g cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp (ala-endotheline) in 400 ~l phosphate buffered saline (pH 7.4) is incubated for one hour at room temperature with a 100 times molar excess of Traut reagent (2.6 mg imino thiolane in 400 ~l triethanolamine hydrochloride buffer pH 8.0). Then the reaction is finished by separating excessive Traut reagent using a gel filtration column (SEC 3000 Beckman). The reaction is checked by determining the free SH groups (according to Grasseti).

Molecular weight: calc.: 2504.9 det.: 2505 (FAB-MS) b) 99mTc complex of 4-mercaptobutyrimidyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp A solution of 0.5 mg of 4-mercaptobutyrimidyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp in 300 ~1 phosphate buffer (Na2HPO4, 0.1 mol/l, pH 9.5) is added to 50 ~l of a 0.15 molar trisodium citrate dihydrate solution and 2.5 ~1 of a 0.2 molar tin(II) chloride dihydrate solution. The reaction ~D933RN.DOC

!::

67 2~ 132~
mixture is added to a pertechnetate solution (0.4-0.9 mCi) from a Mo-99/Tc-99m generator, incubated for 15 min at room temperature and then filtrated (0.2 ~ filter).
Labelling is analysed using HPLC: MERCK nucleosil-column, 125 x 4 mm, 5 ~m; gradient from 100 % A to 100 ~ B within 7.5 min. Eluent A: phosphate buffer (Na2HPO4; 0.01 M; pH
2.0); eluent B: acetonitrile/ phosphate buffer (Na2HPO4; -0.01 M; pH 2.0) 75:25 (V/V); flow rate: 1.0 ml/min.

Example 15 a) 3-Thiopropionyl-gly-asp-his-leu-asp-ile-ile-trp. ~;

A ~olution of 500 ~g gly-asp-his-leu-asp-ile-ile-trp in 400 ~1 phosphate buffered saline is added to a 10 times molar excess of N-succinimidyl-3-(2-pyridylthio) ~ -propionate in dimethylformamide and incubated for 2 hours at room temperature. The present 2-pyride sulphide group i~ then reduced using 25 mM dithiothreitol, pH 4.5. The reaction solution is concentrated under vacuum to a minimum. Then it is purified using preparative HPLC
~gradient: acetonitrile/phosphate buffer). After neutralizing the buffered solutior., the organic solvent portion i5 blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 1040.2 det. 1040 (FAB-MS) b) 99mTc complex of 3-Thiopropionyl-gly-asp-his-leu-asp-ile-ile-trp.

3-Thiopropionyl-gly-asp-his-leu-asp-ile-ile-trp is labelled according to example 2b.

109~-D.I:C

2~132~

Example 16 a) 2-(Acetylthio)succinyl-gly-asp-his-leu-asp-ile-ile-trp.
A solution of 500 ~g gly-asp-his-leu-asp-ile-ile-trp in 50 ~l dimethyl formamide is added to a 10 times molar excess of 2-mercaptoacetyl succinic acid anhydride in 5 ~l dimethylformamide and incubated for 2 hours at room temperature. Then it is purified using preparative HPLC
(gradient: acetonitrile/phosphate buffer). The organic solvent portion is blown off using N2, and the residue is freeze-dried.

Molecular weight: calc. 1126.2 det. 1126 (FAB-MS) b) 99mTc complex of 2-(Acetylthio)succinyl-gly-asp-his-leu-asp-iile-ile-trp.

2-(Acetylthio)~uccinyl-gly-asp-his-leu-asp-ile-ile-trp iB
labelled according to example 2b.
Example 17 a) Reduction of cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-L~
cys-his-leu-asp-ile-ile-trp (endotheline 1) A solution of 0.5 mg cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp in 500 ~l phosphate buffered saline (pH 7.4) is mixed with 18 ~l mercapto ethanol and incubated for 30 min at room temperature; the excessive reductant is separated.

~D93UN . DOC

69 2 1 l 3 2 ~
b) 99mTc complex of cys-ser-cys-ser-ser-leu-met-asp~
lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp A solution of 0.5 mg of the reduced endotheline 1 in 300 ~l phosphate buffer (Na2HPO4, 0.5 mol/l, pH 9.5) i9 added ~ -~
to 50 ~l of a 0.15 molar trisodium citrate dihydrate solution and 2.5 ~l of a 0.2 molar tin(II) chloride dihydrate solution. The reaction mixture is added to a --pertechnetate solution (0.4-0.9 mCi) from a Mo-99/Tc-99m generator, incubated for 10 min at room temperature and then filtrated (0.2 ~ filter). Labelling is analy~ed using HPLC: MERCK nucleosil-column, 125 x 4 mm, 5 ~m;
gradient from 100 ~ A to 100 ~ B within 7.5 min. Eluent A: phosphate buffer (Na2HPO4; 0.01 M; pH 2.0); eluent B:
acetonitrile/phosphate buffer (Na2HPO4; 0.01 M; pH 2.0) 50 : 50 (V/V); flow rate: 1.0 ml/min.

IW33BN.DOC

Claims (40)

1. Complexes of compounds of the general formula (I) E-L-(K)b (I) containing metal ions with the atomic numbers 21-32, 37-39, 42-51, and 57-83, wherein E is a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, or a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists carrying free thiol groups and directly binding a metal ion;

L is a direct linkage or a Z1-R-Z2 residue, wherein R is a unbranched, branched, saturated or unsaturated C1-20-alkyl group, optionally interrupted by one or several oxygen and/or sulphur atoms and/or carbonyl, -NHCO-, -N(C1-6 alkyl)CO-, -NH- and -N(C1-6 alkyl) groups, and optionally substituted with hydroxy and/or epoxy groups;

Z1 and Z2 are, independent of each other, an -O-, -S-, -(C=O)O-, -NH-(C=S)NH-, -(C=O)-, -(C=S)O-, -NH-, -NH-(C=O)-, or -NH-(C=S)- group, or a residue of formula .alpha.

(.alpha.) wherein s and t are, independent of each other, the integers 0, 1, 2, or 3, ring B represents a phenyl or cyclohexyl group, and Z1 and Z2 have the abovementioned meaning, b represents the integers 0 or 1, K is a chelating agent residue of the general formula II A or II B
(II A) (II B) wherein R2, R3, and R5 are, independent of each other, a hydrogen atom, a (C1-6 alkyl)CO, (C6-8 aryl)CO, or (C7-9 arylalkyl)CO residue, optionally substituted with a hydroxyl group, a C1-4 alkoxy, a carboxyl, or a sulphonic acid group, and R4 represents a residue of either formula II C
or II D
(II C) (II D) wherein the carbon atoms labelled with an asterisk (*) are bound to the imino groups of formula II B, and wherein n' is an integer 1 or 2, i is any integer from 2 to 6, and TT represents .alpha.- and/or .beta.-amino acids linked together in the usual way through amide bonds;

as well as chelating agent residues derived from dithiosemicarbazone derivatives of formula II E
(II E) wherein R6 is a hydrogen atom or a C1-6 alkyl group;

as well as chelating agent residues derived from bis(aminothiol) derivatives of formula II F
(II F) wherein R7 to R18 represent, independent of each other, a hydrogen atom, a C1-10 alkyl chain and/or an L-linkage, while o, p, r are either integers 1 or

2;

as well as chelating agent residues derived from propylene aminoxime derivatives of formula II G
(II G) wherein R19 to R24 represent a hydrogen atom or a C1-4 alkyl residue, either identical or different, and independent of each other, m' is either integer 2 or 3;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II H
(II H) wherein X1 is a bond, a methylene group, or a CHY4 group, with one of groups Y1, Y2, Y3 or Y4 representing an L-linkage and the others hydrogen atoms or optionally an oxygen atom, T is a hydrogen atom, an alkaline metal ion, a C1-6 acyl group, a benzoyl group, a hydroxyacetyl group, an acetamido methyl group, a p-methoxy benzyl group, an ethoxy ethyl group, or any other suitable SH protective group, A1, A2, A3 and A4 are hydrogen atoms or C1-6 alkyl groups, either identical or different, and independent of each other;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II J

(II J) wherein R27 represents a hydrogen atom, or a C1-6 alkyl residue optionally substituted with one or two hydroxyl groups, R25 and R26 are a hydrogen atom each, or an oxygen atom together A is a hydroxyl or mercapto group, Y is a hydrogen atom, a carboxy or sulphonyl residue, and Z is a carbon atom or a nitrogen atom;

as well as chelating agent residues derived from amino polycarboxylic acids of either formula II K
or II L
(II K) (II L) wherein n and m are either integer 0, 1, 2, 3, or 4, with n plus m not exceeding 4, a is an integer 2, 3, 4, or 5 k is an integer 1, 2, 3, 4, or 5, l is an integer 0, 1, 2, 3, 4, or 5, and q is an integer 0, 1, or 2, U represents a hydrogen atom, or a C1-6 alkyl group optionally substituted with one or several hydroxy groups and containing an Linkage, each residue X represents hydrogen atoms, COOH
groups, ester groups, or amide groups with 1 to 6 carbon atoms in the alkyl residue, independent of each other, R1 is a binding to L or a hydrogen atom;

as well as chelating agent residues of formula II
M, Cp(aa)Cp- (II M) wherein Cp is a protected cysteine and (aa) one of the naturally occurring amino acids;

as well as cysteine-rich amino acid sequences of the metalloid thionines , , , and analogous sequences in which serine has been replaced by threonine, glycine, or alanine;

as well as endotheline derivatives, endotheline partial sequences, endotheline analogues or endotheline antagonists that are labelled using radioactive iodine isotopes.

2. Compounds according to Claim 1, characterized in that the metal ion M is an ion of an isotope of Tc, Re, In, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Sa, Y, Gd, Tb, Dy, Ho, Er, or La.

3. Compounds according to Claims 1 or 2, characterized in that the endothelines E comprise the following sequence of amino acids or parts thereof.

4. Compounds according to Claims 1 or 2, characterized in that the parts of endothelines E
comprise the amino acid sequence -his-leu-asp-ile-ile-trp-.

5. Compounds according to Claims 1 or 2, characterized in that the endotheline analogues comprise one of the following sequences of amino acids:
;
;
;
;
;
;
;
;
or parts thereof.

6. Compounds according to Claims 1 or 2, characterized in that the endotheline antagonists E

comprise one of the following sequences of amino acids:
-D trp-D asp-pro-D val-leu- or -D glu-ala-allo D ile-leu-D trp-

7. Compounds according to Claims 1 or 2, characterized in that the alkylene group representing L is unbranched, branched, cyclic, aliphatic, aromatic, or arylaliphatic.

8. Compounds according to Claims 1 or 2, characterized in that L represents Z1-R-Z2, wherein Z1 and Z2 are, independent of each other, a -(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)- group, and R is an unbranched mono- to decamethylene group or a residue of formula .alpha.
(.alpha.) wherein s equals 1 and t equals 0, ring B is phenylene, and Z1 and Z2 are, independent of each other, a -NH-(C=S)-, -NH-(C=S)NH-, -(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)- group.

9. Compounds according to Claims 1 or 2, characterized in that the complexing agent residue K
comprises a 4-carboxyethylphenylglyoxal-bis-(N-methylthio-semicarbazone)-N-hydroxysuccinimide ester residue, a 6-(4'-isothiocyanatobenzyl)-3,3,9,9-tetramethyl-4,8-diazaundecane-2,10-dion-dioxime residue, a 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bis-salicylidenamine residue, a 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bis-[5-(sulpho)salicylidenamine residue, a N,N'-bis[2-mercaptopyridyl)methyl]-2-methyl-2-(4-isothiocyanatobenzyl)-1,3-propanediamine residue, an S-benzoylthioacetylglycylglycyl glycine residue, a N,N'-bis(benzoylthioacetyl)-2,3-diaminopropionic acid residue a N,N'-bis(benzoylthioacetyl)-3,4-diaminobutyric acid residue, a N,N'-bis(benzoylthioacetyl)-4,5-diaminopentanoic acid residue, a N,N'-1,2-ethylene diyl-bis-(2-mercapto-1-carboxy-ethylamine) residue, a cys(acm)-gly-cys(acm)-gly-gly-arg-gly-asp-ser residue, an ethylenediaminotetraacetic acid residue, a diethylenetriaminopentaacetic acid residue, a trans-1,2-cyclohexane diaminotetraacetic acid residue, a 1,4,7,10-tetraazacyclododecanetetraacetic acid residue, a 1,4,7-triazacyclononanetriacetic acid residue, a 1,4,8,11-tetraazatetradecane tetraacetic acid residue, a 1,5,9-triazacyclododecanetriacetic acid residue, a 1,4,7,10-tetraazacyclododecanetriacetic acid residue, or a 3,6,9,15-tetraazabicyclo[9,3,15]-pentadeca-1(15),11,13-trien-triacetic acid residue.

10.Complexes of compounds of the general formula (I) containing metal ions as defined in Claim 1:

a) 99mTc complex of S- benzoylthioacetyl-gly-gly-gly-gly-asp-his-leu-asp-ile-ile-trp, b) 99mTc complex of N,N'-bis(S-benzoylthioacetyl)-3,4-diaminobutyryl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, c) 99mTc complex of 3-[p-phenylglyoxal-di(N-methylthio semicarbazone)]-propionyl-cys-ser-cys-ser-ser-trp-leu-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, d) 99mTc complex of 3,6-diaza-1,8-dimercapto-2,7-bis-(carbonyl-gly-his-leu-asp-ile-ile-trp) octane, e) 99mTc complex of {[(3,3,9,9-tetramethyl-4,8-diaza-undecyl-2,10-dion-dioxime)-6-yl]methylphen-4'-yl}
aminothiocarbonyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe -cys-his-leu-asp-ile-ile-trp, f) 99mTc complex of N,N'-bis(S-benzoylthioacetyl)-4,5-diamino-1-oxo-pentyl-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, g) 99mTc complex of {[2,6-diaza-1,7-di(2-hydroxy-phenyl)-4-methyl-hept-4-yl]-methyl-phen-4'-yl}
aminothiocarbonyl -cys-thr-cys-phe-thr-tyr-lys-asp-lys-glu-cys-val-tyr-tyr-cys-his-leu-asp-ile-ile-trp, h) 99mTc complex of {[2,6-diaza-1,7-di(2-hydroxy-5-sulphophenyl)-4-methyl-hept-4-yl]-methylphen-4'-yl}
aminothiocarbonyl-ala-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr -phe-ala-his-leu-asp-ile-ile-trp, i) 99mTc complex of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp, k) 111In complex of N-[3,6,9-triaza-1-oxo-3,6,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp, l) Gd(III) complex of N-[3,6,9-triaza-1-oxo-3,5,9,9-tetra-(hydroxycarbonylmethyl)-nonyl]-gly-his-leu-asp-ile-ile-trp, sodium salt, m) Gd(III) complex of 1-{2-hydroxy-3-[4-(gly-his-leu-asp-ile-ile-trp-thiouridyl)phenoxy]propyl}
1,4,7,10-tetraaza-4,7,10-tris-(carboxylatomethyl)-cyclododecane, n) 99mTc complex of cys(acm)-gly-cys(acm)-cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, o) 99mTc complex of cyclo(trp-leu-val-pro-asp)-cys(acm)-gly-cys(acm), p) 99mTc complex of 4-mercaptobutyrimidyl-cys-ser-ala-ser-ser-leu-met-asp-lys-glu-ala-val-tyr-phe-cys-his-leu-asp-ile-ile-trp, r) 99mTc complex of 3-thiopropionyl-gly-asp-his-leu-asp-ile-ile-trp, s) 99mTc complex of 2-(acetylthio)succinyl-gly-asp-his-leu-asp-ile-ile-trp, or t) 99mTc complex of cys-ser-cys-ser-ser-leu-met-asp-lys-glu-cys-val-tyr-phe-cys-his-leu-asp-ile-ile-trp.

11.Compounds according to Claim 1, characterized in that the radioactive iodine isotopes are 131I, 125I, and 123I,

12.Compounds of the general formula (I) E-L-(R)b (I) wherein E is a residue derived from endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists, L is a direct linkage or a Z1-R-Z2 residue, wherin R is a unbranched, branched, saturated or unsaturated C1-20-alkyl group, optionally interrupted by one or several oxygen and/or sulphur atoms and/or carbonyl, -NHCO-, -N(C1-6 alkyl)CO-, -NH- and -N(C1-6 alkyl) groups, and optionally substituted with hydroxy and/or epoxy groups;

Z1 and Z2 are, independent of each other, an -O-, -S-, -(C=O)O-, - NH-(C=S)NH-, -(C=O)-, -(C=S)O-, -NH-, -NH-(C=O)-, or -NH-(C=S)- group, or a residue of formula a (.alpha.) wherein s and t are, independent of each other, the integers 0, l, 2, or 3, ring B represents a phenyl or cyclohexyl group, and Z1 and Z2 have the abovementioned meaning, b represents the integers 0 or 1, K is a chelating agent residue of the general formula II A or II B
(II A) (II B) wherein R2, R3, and R5 are, independent of each other, a hydrogen atom, a (C1-6 alkyl)CO, (C6-8 aryl)CO, or (C7-9 arylalkyl)CO residue, optionally substituted with a hydroxyl group, a C1-4 alkoxy, a carboxyl, or a sulphonic acid group, and R4 represents a residue of either formula II C
or II D
(II C) (II D) wherein the carbon atoms labelled with an asterisk (*) are bound to the imino groups of formula II B, and wherein n' is an integer 1 or 2, i is any integer from 2 to 6, and TT represents .alpha.- and/or .beta.-amino acids linked together in the usual way through amide bonds;

as well as chelating agent residues derived from dithiosemicarbazone derivatives of formula II E
(II E) wherein R6 is a hydrogen atom or a C1-6 alkyl group;

as well as chelating agent residues derived from bis(aminothiol) derivatives of formula II F

(II F) wherein R7 to R18 represent, independent of each other, a hydrogen atom, a C1-10 alkyl chain and/or an L-linkage, while o, p, r are either integers 1 or 2;

as well as chelating agent residues derived from propylene aminoxime derivatives of formula II G
(II G) wherein R19 to R24 represent a hydrogen atom or a C1-4 alkyl residue, either identical or different, and independent of each other, m' is either integer 2 or 3;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II H

(II H) wherein X1 is a bond, a methylene group, or a CHY4 group, with one of groups Y1, Y2, Y3 or Y4 representing an L-linkage and the others hydrogen atoms or an oxygen atom, if any, T is a hydrogen atom, an alkaline metal ion, a C1-6 acyl group, a benzoyl group, a hydroxyacetyl group, an acetamido methyl group, a p-methoxy benzyl group, an ethoxy ethyl group, or any other suitable SH protective group, A1, A2, A3 and A4 are hydrogen atoms or C1-6 alkyl groups, either identical or different, and independent of each other;

as well as chelating agent residues derived from diamido-dimercapto derivatives of formula II J
(II J) wherein R27 represents a hydrogen atom, or a C1-6 alkyl residue optionally substituted with one or two hydroxyl groups, R25 and R26 are a hydrogen atom each, or an oxygen atom together A is a hydroxyl or mercapto group, Y is a hydrogen atom, a carboxy or sulphonyl residue, and Z is a carbon atom or a nitrogen atom;

as well as chelating agent residues derived from amino polycarboxylic acids of either formula II K
or II L
(II K) (II L) wherein n and m are either integer 0, 1, 2, 3, or 4, with n plus m not exceeding 4, a is an integer 2, 3, 4, or 5 k is an integer 1, 2, 3, 4, or 5, 1 is an integer 0, 1, 2, 3, 4, or 5, and q is an integer 0, 1, or 2, U represents a hydrogen atom, or a C1-6 alkyl group optionally substituted with one or several hydroxy groups and containing an L-linkage, each residue X represents hydrogen atoms, COOH
groups, ester groups, or amide groups with 1 to 6 carbon atoms in the alkyl residue, independent of each other, R1 is an L-linkage or a hydrogen atom;
as well as chelating agent residues of formula II M, Cp(aa)Cp - (II M) wherein Cp is a protected cysteine and (aa) one of the naturally occurring amino acids;

as well as cysteine-rich amino acid sequences of the metalloid thionines , , , and analogous sequences in which serine has been replaced by threonine, glycine, or alanine.

13.Compounds according to Claim 12, characterized in that the endothelines E include the following sequence of amino acids or parts thereof.

14.Compounds according to Claim 12, characterized in that the parts of endothelines E comprise the amino acid sequence -his-leu-asp-ile-ile-trp-.

15.Compounds according to Claim 12, characterized in that the endotheline analogues comprise one of the following sequences of amino acids ;
;
;
;
;
;

;
;
or parts thereof.

16.Compounds according to Claim 12, characterized in that the endotheline antagonists E comprise one of the following sequences of amino acids:
-D trp-D asp-pro-D val-leu, or -D glu-ala-allo D ile-leu-D trp-.

17.Compounds according to Claim 12, characterized in that the alkylene group representing L is unbranched, branched, cyclic, aliphatic, aromatic, or arylaliphatic.

18.Compounds according to Claim 12, characterized in that L stands for Z1-R-Z2, wherein Z1 and Z2 are, independent of each other, a -(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)- group, and R is an unbranched mono- to decamethylene group or for a residue of formula .alpha.

(.alpha.) wherein s equals 1 and t equals 0, ring B is phenylene, and Z1 and Z2 are, independent of each other, a -NH-(C=S)-, -NH-(C=S)NH-, -(C=O)O-, -(C=O)-, -NH-, -NH-(C=O)- group.

19.Compounds according to Claim 12, characterized in that the complexing agent residue K comprises a 4-carboxyethylphenylglyoxal-bis-(N-methylthio-semicarbazone)-N-hydroxysuccinimide ester residue, a 6-(4'-isothiocyanatobenzyl)-3,3,9,9-tetramethy-4,8-diazaundecane-2,10-dion-dioxime residue, a 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bis-salicylidenamine residue, a 2-methyl-2-(4-isothiocyanatobenzyl)-N,N'-propylene-bis-[5-(sulpho)salicylidenamine residue, a N,N'-bis[2-mercaptopyridyl)methyl]-2-methyl-2-(4-isothiocyanatobenzyl)-1,3-propanediamine residue, an S-benzoylthioacetylglycylglycyl glycine residue, a N,N'-bis(benzoylthioacetyl)-2,3-diaminopropionic acid residue a N,N'-bis(benzoylthioacetyl)-3,4-diaminobutyric acid residue, a N,N'-bis(benzoylthioacetyl)-4,5-diaminopentanoic acid residue, a N,N'-1,2-ethylene diyl-bis-(2-mercapto-1-carboxy-ethylamine) residue, a cys(acm)-gly-cys(acm)-gly-gly-arg-gly-asp-ser residue, an ethylenediaminotetraacetic acid residue, a diethylenetriaminopentaacetic acid residue, a trans-1,2-cyclohexane diaminotetraacetic acid residue, a 1,4,7,10-tetraazacyclododecanetetraacetic acid residue, a 1,4,7-triazacyclononanetriacetic acid residue, a 1,4,8,11-tetraazatetradecane tetraacetic acid residue, a 1,5,9-triazacyclododecanetriacetic acid residue, a 1,4,7,10-tetraazacyclododecanetriacetic acid residue, or a 3,6,9,15-tetraazabicyclo[9,3,15]-pentadeca-1(15),11,13-trien-triacetic acid residue.

20 Process for preparing complexes of compounds of the general formula (I) containing metal ions, characterized in that a) a radioactive metal ion in the form of its permetallate is reacted in a way known in the art with a compound of the general formula (I) E-L-(K)b (I) in the presence of a reducing agent and optionally an auxiliary ligand, or b) a suitable salt or oxide of a suitable paramagnetic and/or radioactive cation is reacted in a way known in the art with a compound of the general formula (I) E-L-(K)b (I) or c) the disulphide bridges present in the endothelines, endotheline derivatives, partial endotheline sequences, endotheline analogues, or endotheline antagonists are cleaved in a way known in the art, or that free thiol groups are produced using suitable processes e.g. the Trauts process which react with the radioactive metal ion in the form of a permetallate and in the presence of a reducing agent and optionally an auxiliary ligand, or d) radioactive iodine isotopes are introduced in the compound of the general formula II in a way known in the art using the chloramine-T process, or the lactoperoxidase process, or the Bolton-Hunter process, or the iodogen process, or another known process.

21.Process according to Claim 20a, characterized in that technetium-99m or Re are used in the form of pertechnetate or perrhenate.

22 Process according to Claim 20b, characterized in that 111In is used as a radioactive cation.

23.Process according to Claim 20b, characterized in that Gd is used as a paramagnetic cation.

24 Process according to Claim 20c, characterized in that technetium-99m or Re are used in the form of pertechnetate or perrhenate.

25 Process according to Claim 20d, characterized in that 131I, 125I, or 123I is used as a radioactive iodine isotope.

26 Process for preparing a compound of the general formula (I), characterized in that an endotheline, endotheline derivative, endotheline partial sequence, endotheline analogue, or endotheline antagonist is reacted with a compound of the formula (III) (K)b-L-H (III) wherein K, L, and b have the meaning given in Claim 1.

27.Process according to Claim 26, characterized in that E
and L are linked through an ester, ether, thioether, thioester, amide, or thioamide linkage.

28.Diagnostic agent, characterized by the content of a compound according to Claims 1 to 11 and suitable excipients and carriers.

29.Agent according to Claim 28, characterized in that the complex of the compound of the general formula (I) contains a radioactive metal ion.

30.Agent according to Claims 28 or 29, characterized in that the radioactive metal ion is Tc, Re, In, or I.

31.Agent according to Claim 28, characterized in that the complex of the compound of the general formula (I) contains a paramagnetic metal ion.

32.Agent according to Claim 31, characterized in that the paramagnetic metal ion is Gd, Tb, Dy, Ho, Er, or Fe.

33.Agent according to Claim 28, characterized in that the metal ion shows a sufficient absorption for X-rays.

34.Cold kit for the preparation of radiopharmaceuticals comprising of a compound of the general formula (I) according to Claim 12 and optionally an auxiliary ligand, present either in dry or dissolved form, directions for reacting the described compound with technetium-99m or Re in the form of a pertechnetate or perrhenate solution.

35.Method for imaging pathological vascular changes, characterized in that an agent according to Claim 28 is used as a contrast medium.

36.Method according to Claim 35, characterized in that the contrast medium is used for radiodiagnostics.

37.Cold kit containing endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent that are capable of binding metal ions, and optionally metal ions bonded to the latter.

38.Cold kit according to Claim 37, characterized in that the bound metal ion is not radioactive and can be easily replaced by a radioactive isotope.

39.Hot kit containing endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent, and a radioactive iodine atom bonded to the latter.

40.Use of the cold kit according to Claim 37 whereby the cold kit comprises a closeable vessel containing the predetermined quantity of endothelines, endotheline derivatives, endotheline partial sequences, endotheline analogues, or endotheline antagonists bonded to a peptide, a derivative, or a chelating agent capable of binding metal atoms, and containing a quantity of a reducing agent sufficient to label the compound with 99mTc in order to produce a radiopharmaceutical formulation.