IN VIVO STABLE HG-197(M) COMPOUNDS, METHOD FOR THE PRODUCTION THEREOF AND USE THEREOF IN NUCLEAR MEDICAL DIAGNOSTICS AND ENDORADIONUCLIDE THERAPY (THERANOSTICS)

Abstract

The present invention relates to in vivo stable .sup.197(m)Hg compounds according to formula (I) for use in nuclear medical diagnostics and endoradionuclide therapy (theranostics), particularly the treatment of cancer, a method for the production of the .sup.197(m)Hg compounds comprising the step of radiolabeling of organic precursor compounds with NCA .sup.197(m)Hg by electrophilic substitution; and the use of the .sup.197(m)Hg compounds for nuclear medical diagnostics and endoradionuclide therapy (theranostics), particularly the treatment of cancer.

Claims

1. (canceled)

2. A .sup.197(m)Hg compound according to one of the following formulas (I), (Ia), (Ib) or (Ic) ##STR00035## wherein each X and each W are independently selected from H, unsubstituted or substituted alkyl groups, alkoxy groups with formula OR.sup.1, amide groups with formula CON(R.sup.1).sub.2, carboxy groups with formula COOR.sup.1, aryl and heteroaryl groups, wherein R.sup.1 is selected from H, unsubstituted or substituted C1 to C15-alkyl, succinimidyl, aryl or heteroaryl groups, wherein Y is selected from substituted dithiocarbamates, substituted thiolates, unsubstituted or substituted aryl or heteroaryl groups, wherein Z is selected from CH, S, N, and O, wherein Met is selected from Fe, Cr, Mn, Mo, Ru, and Rh.

3. The .sup.197(m)Hg compound according to claim 2, wherein n and o are 1, as shown in formulas (I), (Ia), (Ib) or (Ic), ##STR00036##

4. The .sup.197(m)Hg compound according to claim 2, having a specific activity of at least 100 GBq/mol based on the amount of mercury.

5. The .sup.197(m)Hg compound according to claim 2, wherein X.sub.n and/or Y comprise at least one amino acid, peptide, protein, antibody, oligonucleotide, alkaloid residue and/or aliphatic spacer.

6. The .sup.197(m)Hg compound according to claim 2, wherein Y is selected from unsubstituted or substituted phenyl groups as shown in formula (IV) ##STR00037## wherein R.sup.7 is selected from H, unsubstituted or substituted alkyl groups, alkoxy groups with formula OR.sup.8, amide groups with formula CON(R.sup.8).sub.2, carboxy groups with formula COOR.sup.8, aryl or heteroaryl groups, wherein R.sup.8 is selected from H, unsubstituted or substituted C1 to C15-alkyl, succinimidyl, aryl or heteroaryl groups.

7. The .sup.197(m)Hg compound according to claim 6, wherein n is 1, wherein R.sup.7 and X are identically and wherein the phenyl groups are linked by at least one aliphatic or aromatic spacer molecule as shown in formula (VI) ##STR00038## wherein X is selected from H, unsubstituted or substituted alkyl groups, alkoxy groups with formula OR.sup.1, amide groups with formula CON(R.sup.1).sub.2, carboxy groups with formula COOR.sup.1, aryl or heteroaryl groups, wherein R.sup.1 is selected from H, unsubstituted or substituted C1 to C15-alkyl, aryl or heteroaryl groups.

8. A method for nuclear medical diagnostics and endoradionuclide therapy of cancer comprising the step of administering to a subject in need thereof a pharmaceutical composition containing a therapeutically effective amount of a .sup.197(m)Hg compound according to claim 2.

9. A method for the production of .sup.197(m)Hg compounds according to claim 2, comprising the steps: a) Provision of an organic precursor compound, b) Synthesis of no carrier added (NCA) .sup.197(m)Hg, c) Radiolabeling of the organic precursor compound with the no carrier added (NCA) .sup.197(m)Hg by electrophilic substitution.

10. The method according to claim 9, wherein the organic precursor compound is an organotin precursor compound, a boron precursor compound or a silicon precursor compound.

11. The method according to claim 9, wherein the organic precursor compound is a trialkyl-tin precursor compound.

12. The method according to claim 9, wherein the synthesis of NCA .sup.197(m)Hg according to step b) is carried out by irradiation of gold (Au) with a cyclotron.

13. The method according to claim 9, wherein the radiolabeling of the organic precursor compound according to step c) is carried out at a pH value between pH 1.0 and 5.0 to form asymmetric .sup.197(m)Hg compounds.

14. The method according to claim 9, wherein the radiolabeling of the organic precursor compound according to step c) is followed by reaction of activated ester groups by ester hydrolysis, reaction with amino groups or reaction with hydroxyl groups of an amino acid, peptide, protein, antibody, oligonucleotide, alkaloid residue and/or aliphatic spacer.

15. The method according to claim 9, wherein in step a) an organic precursor compound according to formulas (I.sub.prec), (Ia.sub.prec), (Ib.sub.prec) or (Ic.sub.prec) is provided: ##STR00039## wherein each X and each W are independently selected from H, unsubstituted or substituted alkyl groups, alkoxy groups with formula OR.sup.1, amide groups with formula CON(R.sup.1).sub.2, carboxy groups with formula COOR.sup.1, aryl or heteroaryl groups, wherein R.sup.1 is selected from H, unsubstituted or substituted C1 to C15-alkyl, aryl or heteroaryl groups, Z is selected from CH, S, N, and O, M is Sn, B or Si; wherein Met is selected from Fe, Cr, Mn, Mo, Ru and Rh, R.sup.10 is selected from H, unsubstituted or substituted C1 to C15-alkyl, aryl or heteroaryl groups, and i is 2 or 3.

16. A method for treatment of cancer comprising the step of administering to a subject in need thereof a pharmaceutical composition containing a therapeutically effective amount of a .sup.197(m)Hg compound according to claim 2.

Description

FIGURES AND EXAMPLES

[0117] The present invention will now be further explained by the following non-limiting figures and examples.

[0118] FIG. 1 shows the fractionated elution of .sup.197(m)Hg mercury chloride in 6 M HCl and .sup.198Au+.sup.196Au containing chloroauric acid in 0.1 M HCl.

[0119] FIG. 2 shows (A) Radiochromatogram of Phenyl-.sup.197(m)Hg-dithiocarbamate and (B) UV-chromatogram of non-radioactive Phenyl-Hg-dithiocarbamate (reference).

GENERAL SYNTHETIC TECHNIQUES

[0120] All Chemicals were used without further purification and in the highest degree of purity.

[0121] Sodium hydroxide in suprapur quality was purchased from Merck (Darmstadt, Germany). Methyl isobutyl ketone (MIBK) was purchased from Sigma-Aldrich (St. Louis, USA). The routine activity measurement was performed with an Isomed 2000 from MED (Nuklear-Medizintechnik Dresden GmbH, Dresden, Germany) calibrated by -ray spectroscopy measurements after decaying .sup.197mHg. ICP-MS measurements were carried out on an ELAN 9000 (PerkinElmer SCIEX, Waltham, USA).

Gamma-Ray Spectroscopy

[0122] For -ray spectroscopy measurements a reverse electrode HPGe detector (CANBERRA GR2018, 19.6% rel. efficiency) in a low-background Pb shielding was used with the sample at 10 cm distance from the detector end cap. It was operated with the software InterWinner version 7.1. The system was calibrated using a mixed standard solution (57Co, 85Sr, 88Y, 60Co, 109Cd, 113Sn, 137Cs, 139Ce, 203Hg, 241Am) with a volume of 0.38 mL in the tip of a 1.5 mL Eppendorf vial. The energy depending detector efficiency was calculated from these calibration points using the algorithms of the spectroscopy software. The samples were measured in similar geometry, but smaller volume of 1-10 l in the tip of a 1.5 mL Eppendorf vial thus, no further corrections were necessary with except of decay correction. Pile-up effects were observed, especially at higher activities. Nevertheless, no corrections are made, because the effects are less than the simple standard deviation and thus negligible. For the determination of Hg-activities only the -ray lines >100 keV have been used, in particular for the isomer 197mHg only the lines 134 keV and 165 keV of the isomeric transition and for the isomer 197Hg only the lines 191 keV and 269 keV are discussed in the activity calculation.

NMR and IR Spectroscopy

[0123] .sup.1H and .sup.13C NMR spectra were recorded with a Varian Inova-400 spectrometer. The chemical shifts were reported relative to the standard tetramethylsilane (TMS). IR spectra were measured with a Fisher Scientific Nicolet iS5 FTIR spectrometer.

Thin Layer Chromatography (TLC)

[0124] Thin layer chromatography was performed using RP18 plates (Merck), developed in a 1:1 mixture H.sub.2O with 0.1% trifluoroacetic acid (TFA) (A) and CH.sub.3CN with 0.1% TFA (B) and analyzed with a Raytest Linearanalyser RITA.

[0125] Radio-TLC is the detection of radioactive species separated by TLC with radiation detector to determine the radiochemical purity or to quantify the radioactive species.

[0126] The radiochemical yield is the yield of the radionuclide and was calculated by the specific activity of the .sup.197(m)Hg compound divided by the specific activity of the no carrier added (NCA) .sup.197(m)Hg.

High-Performance Liquid Chromatography (HPLC) Measurements

[0127] Radiochemical purity was determined by radio-HPLC. All HPLC runs are performed under the same conditions with the same HPLC-equipment. Column: Zorbax C18 column with inner diameter of 8 mm. Mobile phase: H.sub.2O with 0.1% TFA (A) and CH.sub.3CN with 0.1% TFA (B). Flow rate: 3 mL/min. HPLC gradient of B phase: in 0 to 20 min from 45% to 80%, in 20 to 25 min from 80% to 100%.

Mass Spectrometry (Electrospray Ionization (ESI)-MS, Matrix-Assisted Laser Desorption/Ionization (MALDI)-MS)

[0128] For mass spectrometry a QuadroLC by Micromass with electrospray ionisation (ESI) mode and a Bruker MALDI-TOF MS instrument (MALDI) were used.

1. Synthesis of an Organic Precursor Compound

N.SUP.1.,N.SUP.3.-bis(3-iodobenzyl)isophthalamide

[0129] ##STR00016##

[0130] 3-iodobenzylamine hydrochloride salt (4 g, 14.84 mmol) was dissolved in chloroform (100 ml) in a 250 ml round-bottomed flask. To this was added triethylamine (10.3 ml, 0.074 mol) followed by isophthaloyl chloride (1.51 g, 7.42 mmol). The flask was fitted with a CaCl.sub.2) drying tube and the colourless solution was left to stir at room temperature overnight. The reaction was monitored by TLC using 19:1 dichloromethane (DCM)/methanol (MeOH). The reaction mixture was washed with 3:1 water/saturated NaHCO.sub.300 (350 ml), then with 0.1 M HCl.sub.(aq.) (350 ml), then with deionized water (230 ml). The product is mostly insoluble in chloroform and precipitates during the aqueous washes, thus further dilution with chloroform helps separation. The product was purified by simple recrystallization of cooling the chloroform. Impurities dissolved in the solvent were decanted. This process was repeated to increase yield. The product was washed lightly with cold chloroform and after drying left a white powder (1.02 g, 92% yield).

[0131] .sup.1H NMR (400 MHz, CDCl.sub.3) (ppm): 8.23 (s, 1H), 7.92 (dd, J=7.8, 1.6 Hz, 2H), 7.64 (s, 2H), 7.59 (d, J=7.9 Hz, 2H), 7.48 (t, J=7.8 Hz, 1H), 7.28 (s, 1H), 7.04 (d, J=7.8 Hz, 2H), 6.84 (d, J=5.3 Hz, 2H), 4.52 (d, J=5.8 Hz, 4H),

[0132] .sup.13C NMR (101 MHz, CDCl.sub.3) (ppm): 166.57, 140.37, 136.93, 134.52, 130.64, 130.40, 129.27, 127.32, 125.67, 94.78, 43.61.

N.SUP.1.,N.SUP.3.-bis(3-(trimethylstannyl)benzyl)isophthalamide

[0133] ##STR00017##

[0134] N.sup.1,N.sup.3-bis(3-iodobenzyl)isophthalamide (0.97 g, 1.63 mmol) was dissolved in 1,4-dioxane (20 ml) in a 50 ml 3-necked round-bottomed flask. A glass bubbler allowed argon to bubble through the solution with a coiled water condenser attached to the top along with a bubble counter to monitor argon flow. A catalytic amount of tetrakis(triphenylphosphine)palladium(0) (20.4 mg, 16.3 mol) orange crystals were added forming a clear pale yellow solution. This was followed by an excess of hexamethylditin (3.16 ml, 15.26 mmol). Rinsing of sample phials and addition funnel brought the total solvent volume to 30 ml. The reaction mixture was heated by an oil bath (125 C.) and stirred for 8 h. The reaction was monitored by TLC using 1:1 ethanol (EtOH)/n-hexane. The reaction mixture turned a dark orange with a cloudy precipitate. This was filtered to remove most of the brown precipitate. The solvent was removed by evaporation and the product purified by flash column chromatography using EtOH/n-hexane. Drying yielded a white powder (0.164 g, 15% yield).

[0135] .sup.1H NMR (400 MHz, d.sub.6-DMSO) (ppm): 9.11 (broad t, 2H), 8.38 (s, 1H), 8.01 (dd, J=7.8, 1.6 Hz, 2H), 7.58 (t, J=7.8 Hz, 1H), 7.53-7.22 (m, 8H), 4.47 (d, J=5.9 Hz, 4H), 0.25 (s, 18H),

[0136] .sup.13C NMR (101 MHz, CDCl.sub.3) (ppm): 166.41, 143.39, 137.31, 135.72, 135.46, 134.92, 130.12, 129.18, 128.61, 128.22, 125.51, 44.68, -9.35.

2. Production of No-Carrier-Added .SUP.197(m).Hg

[0137] The irradiations were performed at a Cyclone 18/9 cyclotron (IBA, Louvain la Neuve, Belgium, 18 MeV protons) located at Dresden-Rossendorf. A 1.0 mm aluminum foil (high purity aluminum, 99.999%) from Goodfellow (Huntingdon, England) was used as vacuum window. As target material massive high purity gold disks (23 mm diameter, 2 mm thickness, N5 purity 99.999%) were purchased from ESPI (Ashland, USA). Alternative gold targets consisted of a gold foil (12.512.5 mm, 0.25 mm thickness, 99.99+%) or a small gold disk (10 mm diameter, 0.125 mm thickness, 99.99+%, Pt content: 455 ppm quantified per ICP-MS) between an aluminum disk (22 mm diameter, 1 mm thickness, 99.0%, hard) and an aluminum lid (23 mm diameter, 99.0%, hard) purchased from Goodfellow (Huntingdon, England). Hydrochloric acid (30%) and nitric acid (65%) were purchased from Roth (Karlsruhe, Germany) in Rotipuran Ultra quality. Deionized water with >18 MQcm resistivity was prepared by a Milli-Q system (Millipore, Molsheim, France). LN resin was purchased from Triskem International (Bruz, France). The gold target was irradiated for 120 min with a 25 A current of 10 MeV protons resulting in 200 MBq of .sup.197(m)Hg. The irradiated gold foil was dissolved in 700 l of aqua regia (freshly prepared 1 h before EOB from 525 l 30% HCl+175 l 65% HNO.sub.3) at room temperature. The gold disk was completely dissolved after 50 to 60 min. The column preparation was carried out directly before use by loading 3.6 g LN resin slurried with 10 ml of 6 M HCl onto the column and rinsing with additional 30 ml of 6 M HCl. After dilution of the 700 l product solution with 300 l 6 M HCl, this mixture was loaded onto the column and eluted with 6 M HCl in 1 ml aliquots.

[0138] FIG. 1 shows the fractionated elution of .sup.197(m)Hg mercury chloride in 6 M HCl (two major fractions 7+8 and two minor fractions 9+10) and .sup.198Au+.sup.196Au containing chloroauric acid in 0.1 M HCl (fractions 13-22).

3. Radiolabeling of the Organic Precursor Compound with the No Carrier Added (NCA) .SUP.197(m).Hg by Electrophilic Substitution

General Synthetic Procedure for Synthesis of Diphenyl.SUP.nat.Mercury Compounds (Reference)Based on Sn-Precursors:

[0139] A solution of one equivalent mercury (II)-chloride was added to a solution of two equivalents tin-precursor in acetonitrile. The immediately starting precipitation of the product was completed by addition of ice cooled diethyl ether after 2 h mixing at room temperature. Centrifugation followed by washing the residue with cold diethyl ether results in a colorless microcrystalline product.

Bis(4-(N-succinimidyl)benzoate)mercury (II) (Reference)

[0140] ##STR00018##

[0141] A solution of one equivalent mercury (II)-chloride (5.5 mg, 20 mol) in 1.5 ml acetonitrile was added to a solution of two equivalents tin-precursor N-succinimidyl-4-(tri-n-butylstannyl)benzoate (21 mg, 41 mol) in 1.5 ml acetonitrile. The immediately starting precipitation of the product was completed by addition of ice cooled diethyl ether after 2 h mixing at room temperature. Centrifugation followed by washing the residue with cold diethyl ether results in a colorless microcrystalline product.

[0142] Chemical Formula: C.sub.22H.sub.16HgN.sub.2O.sub.8,

[0143] Molecular Weight: 636.97 g/mol,

[0144] .sup.1H-NMR (400 MHz, DMSO-D.sub.6) (ppm): 2.89 (s, 8H); 7.77 (d, 4H); 7.99 (d, 4H),

[0145] .sup.13C-NMR (100 MHz, DMSO-D.sub.6) (ppm): 25.5 (CH.sub.2); 123.5 (C); 128.8 (CH); 137.8 (CH); 161.9 (C); 162.0 (C); 170.3 (C), yield: 7 mg (15.4 mol; 77%),

[0146] ESI.sup.+ m/z: 637 [M]+; 539 [M-NHS]+.

General Synthetic Procedure for Synthesis of Radiolabeled Diphenyl-Mercury SpeciesBased on Sn-Precursors

[0147] The .sup.197(m)Hg chloride stock solution in 0.2 M HCl is adjusted to pH 6 by adding 100 l 0.2 M 2-(N-morpholino)ethanesulfonic acid (MES) buffer and 5-10 l 1 M NaOH. A solution of 1-10 g trialkyltin precursor in 50-100 l dimethyl sulfoxide (DMSO) is added to this buffered .sup.197(m)Hg chloride solution and mixed at 50 C. for 1 h. The completion of the reaction is confirmed by TLC control (acetonitrile (ACN)/H.sub.2O 90:10 (v/v) with 0.1 vol-% trifluoroacetic acid (TFA), instant thin layer chromatography medium (iTLC)-silica gel (SG) and RP18 material).

[.SUP.197(m).Hg] Bis(4-(N-succinimidyl)benzoate)mercury(II)

[0148] ##STR00019##

[0149] The .sup.197(m)Hg chloride solution in 0.2 M HCl is adjusted to pH 6 by adding 100 l 0.2 M 2-(N-morpholino)ethanesulfonic acid (MES) buffer and 5-10 l 1 M NaOH. A solution of 10 g (20 nmol) N-succinimidyl-4-(tri-n-butylstannyl)benzoate in 100 l DMSO is added to 110 l of this buffered .sup.197(m)Hg chloride solution (45 MBq [.sup.197(m)Hg] mercury) and mixed at 50 C. for 1 h. The completion of the reaction is confirmed by TLC control (ACN/H.sub.2O 90:10 (v/v) with 0.1 vol-% trifluoroacetic acid (TFA), instant thin layer chromatography medium (iTLC)-silica gel (SG) and RP18 material).

[0150] Radiochemical yield (TLC): 95%,

[0151] Radiochemical purity (TLC): 95%

[0152] Radio-TLC: R.sub.f=0.45 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

General Synthetic Procedure for Synthesis of Diaryl/Heteroaryl.SUP.nat.Mercury Compounds (HPLC Reference)Based on B-Precursors

[0153] (See Ref. Partyka et al., J. Organometallic Chemistry):

[0154] A mixture of one equivalent mercury (II)-acetate (5 mol), ten equivalents boronic acid (50 mol) and ten equivalents cesium carbonate (50 mol) in 1 ml propane-2-ol was tempered at 50 C. for 20 h. After cooling and drying the mixture by rotary evaporation the product was extracted from the residue with toluene or THF purified by HPLC and identified by mass spectrometry.

Di(thiophen-2-yl)mercury

[0155] ##STR00020##

[0156] A solution of one equivalent mercury (II)-acetate (1.6 mg, 5 mol) in 0.5 ml propan-2-ol was added to a solution of ten equivalents 2-thienylboronic acid (6.4 mg, 50 mol) and cesium carbonate (16 mg, 50 mol) in 1.0 ml propan-2-ol and mixed at 50 C. for 20 h.

[0157] Chemical Formula: C.sub.8H.sub.6HgS.sub.2,

[0158] Molecular Weight: 366.85 g/mol,

[0159] ESI.sup.+ m/z: 369 [M].sup.+.

Bis(5-carboxythiophen-2-yl)mercury

[0160] ##STR00021##

[0161] A solution of one equivalent mercury (II)-acetate (1.6 mg, 5 mol) in 0.5 ml propan-2-ol was added to a solution of ten equivalents 5-(Dihydroxyboryl)-2-thiophenecarboxylic acid (8.5 mg, 50 mol) and cesium carbonate (16 mg, 50 mol) in 1.0 ml propan-2-ol and mixed at 50 C. for 20 h.

[0162] Chemical Formula: C.sub.10H.sub.6HgO.sub.4S.sub.2,

[0163] Molecular Weight: 454.86 g/mol,

[0164] ESI.sup.+ m/z: 457 [M].sup.+.

Di(ferrocenyl)mercury

[0165] ##STR00022##

[0166] A solution of one equivalent mercury (II)-acetate (1.6 mg, 5 mol) in 0.5 ml propan-2-ol was added to a solution of ten equivalents ferroceneboronic acid (11.5 mg, 50 mol) and cesium carbonate (16 mg, 50 mol) in 1.0 ml propan-2-ol and mixed at 50 C. for 20 h.

[0167] Chemical Formula: C.sub.20H.sub.18Fe.sub.2Hg,

[0168] Molecular Weight: 570.64 g/mol,

[0169] ESI.sup.+ m/z: 573 [M].sup.+.

Bis(5-carboxypyridin-3-yl)mercury

[0170] ##STR00023##

[0171] A solution of one equivalent mercury (II)-acetate (1.6 mg, 5 mol) in 0.5 ml propan-2-ol was added to a solution of ten equivalents 5-(dihydroxyboryl)-3-pyridinecarboxylic acid (8.3 mg, 50 mol) and cesium carbonate (16 mg, 50 mol) in 1.0 ml propan-2-ol and mixed at 50 C. for 20 h.

[0172] Chemical Formula: C.sub.12H.sub.8HgN.sub.2O.sub.4,

[0173] Molecular Weight: 444.02 g/mol,

[0174] ESI.sup.+ m/z: 447 [M].sup.+.

(5-Carboxythiophen-2-yl)(phenyl)mercury

[0175] ##STR00024##

[0176] A solution of one equivalent phenylmercury acetate (1.7 mg, 5 mol) in 0.5 ml propan-2-ol was added to a solution of ten equivalents 5-(dihydroxyboryl)-2-thiophenecarboxylic acid (8.5 mg, 50 mol) and cesium carbonate (16 mg, 50 mol) in 1.0 ml propan-2-ol and mixed at 50 C. for 20 h.

[0177] Chemical Formula: C.sub.11H.sub.8HgO.sub.2S,

[0178] Molecular Weight: 404.83 g/mol,

[0179] ESI.sup.+ m/z: 407 [M].sup.+.

General Synthetic Procedure for Synthesis of Radiolabeled Diaryl/Heteroaryl.SUP..Mercury SpeciesBased on B-Precursors

[0180] A solution of 10-100 g aryl boronic acid precursor in 50-100 l ethanol is added to the intended amount .sup.197(m)Hg acetate solution in 0.2 M sodium acetate. The pH of the mixture is then adjusted to pH 8 by adding 100 l 0.2 M 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES) buffer and shaken at 50 C. for 1 h. The completion of the reaction is confirmed by TLC control (acetonitrile (ACN)/H.sub.2O 90:10 (v/v) with 0.1 vol-% trifluoroacetic acid (TFA), instant thin layer chromatography medium (iTLC)-silica gel (SG) and RP18 material).

Di(thiophen-2-yl)mercury

[0181] ##STR00025##

[0182] Radiochemical yield (TLC): 95%,

[0183] Radio-TLC: R.sub.f=0.2 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

Bis(5-carboxythiophen-2-yl)mercury

[0184] ##STR00026##

[0185] Radiochemical yield (TLC): 95%,

[0186] Radio-TLC: R.sub.f=0.9 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

Di(ferrocenyl)mercury

[0187] ##STR00027##

[0188] Radiochemical yield (TLC): 95%,

[0189] Radio-TLC: R.sub.f=0.1 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

Bis(5-carboxypyridin-3-yl)mercury

[0190] ##STR00028##

[0191] Radiochemical yield (TLC): 95%,

[0192] Radio-TLC: R.sub.f=0.9 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

(5-carboxythiophen-2-yl))(phenyl)mercury

[0193] ##STR00029##

[0194] This heteroleptic diaryl mercury compound is accessible in a two-step procedure (analogous to the asymmetric phenylmercury dithiocarbamate derivatives (see next section):

Step 1: Synthesis of .SUP.197(m).Hg phenylmercury Chloride

[0195] The .sup.197(m)Hg chloride stock solution in 0.2 M HCl is diluted by adding 100 l water and 100 l ethanol to improve the solubility of the tin precursor and the lipophilic intermediate. A solution of 10 g trimethylstannyl benzene precursor in 50 l dimethyl sulfoxide (DMSO) is added to this acidic .sup.197(m)Hg chloride solution and mixed at 50 C. for 1 h. The completion of the reaction is confirmed by TLC control (acetonitrile (ACN)/H.sub.2O 90:10 (v/v) with 0.1 vol-% trifluoroacetic acid (TFA), instant thin layer chromatography medium (iTLC)-silica gel (SG) and RP18 material).

Step 2: Reaction of the .SUP.197(m).Hg Phenylmercury Chloride with the Aryl Boronic Acid

[0196] A solution of 50 g 5-carboxy-2-thienylboronic acid in 50 l ethanol is added together with 100 l 0.2 M sodium acetate to the .sup.197(m)Hg phenylmercury chloride. The pH of the mixture is then adjusted to pH 8 by adding 100 l 0.2 M 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES) buffer and shaken at 50 C. for 1 h. The completion of the reaction is confirmed by TLC control (acetonitrile (ACN)/H.sub.2O 90:10 (v/v) with 0.1 vol-% trifluoroacetic acid (TFA), instant thin layer chromatography medium (iTLC)-silica gel (SG) and RP18 material).

[0197] Radiochemical yield (TLC): 60%,

[0198] Radio-TLC: R.sub.f=0.45 (ACN/H.sub.2O 90:10 (v/v) with 1 vol-% trifluoroacetic acid (TFA, RP-18).

Synthesis of Asymmetric Radiolabeled Aryl-Mercury-Dithiocarbamate Derivatives

[.SUP.197(m).Hg] (Diethylcarbamothioyl)thio)(4-((2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)benzoyl-amido)-mercury (II)

Step 1: Phenyl-.SUP.197(m).HgCl Derivatives

[0199] ##STR00030##

[0200] 2 g of the tin precursor N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)-4-(tributylstannyl)benzamide (K08-15) dissolved in 20 l DMSO was added into 50 l 0.1 M HCl solution containing 45.5 MBq [.sup.197(m)Hg]HgCl.sub.2. The reaction mixture was shaken overnight at 25 C. (>12 h). Acidic environment is needed to avoid the formation of symmetric diphenyl mercury species. Excess of organotin precursors were decomposed slowly in acid environment.

Step 2: Ph-.SUP.197(m).Hg-dithiocarbamate Derivatives

[0201] ##STR00031##

[0202] The pH of the phenyl mercury chloride derivatives (step 1) was adjusted to pH 6, adding about 200 l 0.2 M MES buffer (pH 6.0 to 6.2) and about 10 l 0.2 M NaOH, before the dithiocarbamate ligand is added. Then 20 g dithiocarbamate (cw04) containing 50 l 0.2 M MES buffer (pH 6.0 to 6.2) were added into mixture quickly. Then, the reaction mixture was shaken at 50 C. for 60 min.

[0203] Radiochemical purity was determined by radio-HPLC (see FIG. 2). The non-radioactive reference substance of dithiocarbamate arylmercury derivative was used to confirm the labeling product either. FIG. 2 shows a) Radiochromatogram of Phenyl-.sup.197(m)Hg-dithiocarbamate and b) UV-chromatogram of non-radioactive Phenyl-Hg-dithiocarbamate (reference).

4. Ester Hydrolysis

Bis(4-carboxyphenyl)mercury(II) (Reference)

[0204] ##STR00032##

[0205] To a solution of 23 mg (36 mol) Bis(4-(N-succinimidyl)benzoate)mercury(II) in 2 ml dimethylformamide (DMF) 2.88 l 2.5 N NaOH (72 mol) and 1 ml water were added. After mixing 2 h at 50 C. the completion of the reaction was confirmed by TLC control (DCM/MeOH 50:1 (v/v), DC silica gel 60 F.sub.254). The pH was adjusted to pH 3 by addition of acetic acid then the solvent was removed by rotary evaporation and residue redissolved in 2 ml DMF. The product was precipitated by addition of 20 ml cold diethyl ether, filtrated and dried under vacuum, resulting in a white solid.

[0206] Chemical Formula: C.sub.14H.sub.10HgO.sub.4,

[0207] Molecular Weight: 442.82 g/mol,

[0208] .sup.1H-NMR (400 MHz, DMSO-D.sub.6, AcOH-D.sub.4) (ppm): 7.52 (d, 4H); 7.83 (d, 4H),

[0209] .sup.13C-NMR (100 MHz, DMSO-D.sub.6, AcOH-D.sub.4) (ppm): 129.6 (CH); 131.0 (C); 137.7 (CH); 161.6 (C); 168.4 (C), yield: 15.3 mg (34 mol; 94%),

[0210] ESI.sup.+ m/z: 443 [Hg-M].sup.+.

[.SUP.197(m).Hg] Bis(4-carboxyphenyl)mercury (II)

[0211] ##STR00033##

[0212] The solution of [.sup.197(m)Hg] Bis(4-(N-succinimidyl)benzoate)mercury (II) is adjusted to pH 9 by adding 10 l 1 M NaOH and mixed for 1 h at 50 C. The completion of the reaction is confirmed by TLC control (ACN/H.sub.2O 90:10 (v/v) with 0.1 vol-% TFA, ITLC-SG and RP18 material). Finally, the pH is adjusted to pH 6-7 by addition of 10 l 1 M HCl.

[0213] Radiochemical yield (TLC): 95%,

[0214] Radiochemical purity (TLC): 95%

[0215] Radio-TLC: R.sub.f=0.6 (ACN/H.sub.2O 90:10 (v/v) with 0.1 vol-% TFA, RP-18).

5. Synthesis of the [.SUP.197(m).Hg] Bis(4-Carboxyphenyl)Mercury (II)-mAb Cetuximab (C225) Conjugate by Prelabeling with the Labeled Active Ester

[0216] ##STR00034##

[0217] The solution of [.sup.197(m)Hg] Bis(4-(N-succinimidyl)benzoate)mercury (II) is added to a solution of 1 mg size-exclusion chromatography (SEC) purified C225 antibody in HEPES buffer at pH 8. After mixing the pH is adjusted to pH 8.5. After 1 h at 37 C. the progress of the reaction is confirmed by TLC control. (ACN/H.sub.2O 90:10 (v/v) with 0.1 vol-% TFA, ITLC-SG and RP18 material). Unreacted active ester residues were quenched by adding 10 l 1 M tris(hydroxymethyl)aminomethane (TRIS) solution and separated using a PD10 desalting column.

[0218] Radiochemical yield (TLC): 50-70%,

[0219] Radiochemical purity (TLC): 95%,

[0220] Radio-TLC: R.sub.f=0 (ACN/H.sub.2O 90:10 (v/v) with 0.1 vol-% TFA, RP-18).

CITED NON-PATENT LITERATURE

[0221] R. L. Greif, W. J. Sullivan, G. S. Jacobs, R. F Pitts (1956) Distribution of radiomercury administered as labelled chlormerodrin (neohydrin) in the kidneys of rats and dogs. J. Clin. Investig. 35, 38-43. [0222] D. B. Sodee (1964) Letters to the Editor. Hg-197 as a Scanning nuclide. J. Nuc. I. Med. 5, 1964, 74-75. [0223] B. Matricali (1969) Brain scanning by means of .sup.197Hg-labelled neohydrin. Psychiatr. Neurol. Neurochir. 72, 89-95. [0224] M. Walther, S. Preusche, S. Bartel, G. Wunderlich, R. Freudenberg, J. Steinbach, H.-J. Pietzsch (2015) Theranostic mercury: .sup.197(m)Hg with high specific activity for imaging and therapy. Applied Radiation and Isotopes 97, 177-181. [0225] M. Walther, O. Lebeda, S. Preusche, H.-J. Pietzsch, J. Steinbach (2016) Theranostic mercury Part 1: A New Hg/Au separation by a resin based method. Abstract 16th International Workshop on Targetry and Target Chemistry. [0226] G. N. George, R. C. Prince, J. Gailer, G. A. Buttigieg, M. B. Denton, H. H. Harris, I. J. Pickering (2004) Mercury Binding to the Chelation Therapy Agents DMSA and DMPS and the Rational Design of Custom Chelators for Mercury. Chem. Res. Toxicol. 17, 999-1006. [0227] F. S. Mishkin (1966) Clinical brain scanning with .sup.203Hg Neohydrin. J. Indiana State Med. Assoc. 59 (12), 1435-1438. [0228] T. W. Clarkson, L. Magos (2006) The Toxicology of Mercury and Its Chemical Compounds. Critical Reviews in Toxicology. 36, 609-662. [0229] Remington's Pharmaceutical Sciences (1975) 15th Edition. Editor: A. Osol and J. E. Hoover. Mack Publishing Co., Easton, Pa. 18042. [0230] D. V. Partyka, T. G. Gray (2009) Facile syntheses of homoleptic diarylmercurials via arylboronic acids. J. Organometallic Chem. 694, 213-218.