<p>Different prosthetic groups containing a trialkylstannyl- and an electrophilic group have been synthesised and labelled with the accelerator produced ⁷⁶Br (T_1/2=16 h) through oxidative bromination. The labelled prosthetic groups were conjugated to amino-containing macromolecules such as proteins and 5´-modified oligonucleotides.</p><p><i>N</i>-Succinimidyl 4-[⁷⁶Br]bromobenzoate <b>14 </b>was synthesised in 65 % radio-chemical yield and was conjugated to 5´-hexylamino-modified phosphodiester and phosphorothioate oligonucleotides in 12-19 % isolated radiochemical yield. The stability of the ⁷⁶Br-oligonucleotide-conjugates <i>in vivo</i> in rats was investigated. No degradation from the 5´-end, resulting in labelled, low molecular weight compounds was detected. Compound <b>14</b> has also been used for labelling of different proteins in 23-61% radiochemical yield.</p><p><i>N</i>-Succinimidyl-5-[⁷⁶Br]bromo-3-pyridinecarboxylate <b>17</b> and methyl-4-[⁷⁶Br]bromo-benzimidate <b>15 </b>were synthesised from the corresponding trimethylstannyl-compound in 25% and 40 % yield respectively. Compounds <b>14 </b>and <b>17</b> were conjugated to ε-Boc-octreotide in 55 and 50% isolated radiochemical yield respectively after microwave heating. Compound <b>15</b> did not react with octreotide under the conditions investigated. The two ⁷⁶Br-labelled octreotide derivatives showed different lipophilicity and different binding-properties to tissue from meningiomas.</p><p>Hyaluronic acid, a polysaccharide, was modified with tyramine and labelled by oxidative bromination using ⁷⁶Br in 10% radiochemical yield.</p><p>The generator produced ⁶⁸Ga (T_1/2=68 min) was used to label octreotide and oligonucleotides modified with the metal chelating group 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA). ⁶⁸Ga-DOTA-octreotide was isolated in 65% radiochemical yield and a phosphorothioated ⁶⁸Ga-DOTA-oligonucleotide was isolated in 35% radio-chemical yield after 30 min synthesis time.</p><p>Compound<b> 14 </b>was reacted with 3-aminomethylbenzylamine to give compound <b>18</b>. The specific radioactivity<b> </b>of<b> 18 </b>was determined to be 36 GBq/µmol by measuring the ratio between the mass-peaks for the ⁷⁶Br and ⁷⁹Br-compounds using packed-capillary LC-MS.</p>

Different prosthetic groups containing a trialkylstannyl- and an electrophilic group have been synthesised and labelled with the accelerator produced 76Br (T1/2=16 h) through oxidative bromination. The labelled prosthetic groups were conjugated to amino-containing macromolecules such as proteins and 5´-modified oligonucleotides. N-Succinimidyl 4-[76Br]bromobenzoate <b>14 </b>was synthesised in 65 % radio-chemical yield and was conjugated to 5´-hexylamino-modified phosphodiester and phosphorothioate oligonucleotides in 12-19 % isolated radiochemical yield. The stability of the 76Br-oligonucleotide-conjugates in vivo in rats was investigated. No degradation from the 5´-end, resulting in labelled, low molecular weight compounds was detected. Compound <b>14</b> has also been used for labelling of different proteins in 23-61% radiochemical yield. N-Succinimidyl-5-[76Br]bromo-3-pyridinecarboxylate <b>17</b> and methyl-4-[76Br]bromo-benzimidate <b>15 </b>were synthesised from the corresponding trimethylstannyl-compound in 25% and 40 % yield respectively. Compounds <b>14 </b>and <b>17</b> were conjugated to ε-Boc-octreotide in 55 and 50% isolated radiochemical yield respectively after microwave heating. Compound <b>15</b> did not react with octreotide under the conditions investigated. The two 76Br-labelled octreotide derivatives showed different lipophilicity and different binding-properties to tissue from meningiomas. Hyaluronic acid, a polysaccharide, was modified with tyramine and labelled by oxidative bromination using 76Br in 10% radiochemical yield. The generator produced 68Ga (T1/2=68 min) was used to label octreotide and oligonucleotides modified with the metal chelating group 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA). 68Ga-DOTA-octreotide was isolated in 65% radiochemical yield and a phosphorothioated 68Ga-DOTA-oligonucleotide was isolated in 35% radio-chemical yield after 30 min synthesis time. Compound<b> 14 </b>was reacted with 3-aminomethylbenzylamine to give compound <b>18</b>. The specific radioactivity<b> </b>of<b> 18 </b>was determined to be 36 GBq/µmol by measuring the ratio between the mass-peaks for the 76Br and 79Br-compounds using packed-capillary LC-MS.

This thesis describes the synthesis and radiohalogenation of compounds of potential use for tumor targeting. The first section describes the synthesis and radioiodination of DNA intercalating compounds. The compounds are derivatives of 9-aminoacridine, and the anthracyclins daunorubicin and doxorubicin. The precursor compounds were labeled with 125I (T1/2 = 60 days), which is an Auger emitting nuclide. 125I decaying in the close vicinity of DNA is known to have a much higher cell killing effect than 125I decaying in the cytoplasm and some of the labeled compounds prepared in this thesis are currently being tested for use in targeted radionuclide therapy for cancer. The second section describes the radiobromination of closo-carboranes by subjecting the corresponding iodinated compounds to palladium-catalyzed halogen exchange using [76Br]bromide. The 76Br isotope (T1/2 = 16.2 h) is a positron emitting nuclide that is suitable for PET studies. Via the halogen exchange reaction good to excellent radiochemical yields of radiobrominated closo-carboranes were obtained. The results of the present study may prove to be applicable to pharmacokinetic studies of carboranes and their derivatives. The third and final section describes the indirect radiobromination of the trastuzumab anti-HER2 monoclonal antibody and of the anti-HER2 Affibody by means of an “one-pot” procedure using N-succinimidyl-5-(tributylstannyl)-3-pyridinecarboxylate (SPC) and ((4-hydroxyphenyl)ethyl))maleimide (HPEM), respectively. It was found that SPC and HPEM can be efficiently radiobrominated and thereafter coupled to the antibody and Affibody, respectively. The labeled proteins retained their capacity to bind specifically to HER2 expressing SKOV-3 cells in vitro. Application of this method to 76Br might enable the use of PET in the detection of HER2 expression in breast, ovarian, and urinary bladder carcinomas.