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Our recent investigations for the radiosynthesis of [18F]fluoromethyl tosylate have highlighted that choice of quaternary methyl ammonium (QMA) cartridge used during the radiosynthesis can significantly impact the radiochemical yields. Often the details of the QMA cartridge used in fluourine‐18 syntheses are not fully described. However, our studies demonstrate that the type, the size, and nature (method by which it has been conditioned) of the QMA cartridge used during the radiosynthesis can make a significant impact in the labelling efficiency. This paper investigates the use of three QMA cartridges and demonstrates that radiochemical yield (decay corrected) of [18F]fluoromethyl tosylate can increase from 46% to 60% by simply changing the QMA cartridge (and leaving all other reagents and labelling conditions exactly the same). These learnings may be applied to improve the radiochemical yields of a number of [18F]‐fluorinated tracers (and synthons), where the labelling step is base‐sensitive to increase the radiochemical yield, thereby significantly benefiting the radiochemistry and nuclear medicine community. This paper also highlights the necessity of the radiochemistry community to ensure the details of QMA cartridges used in fluorine‐18 chemistry are fully and accurately described, since this will improve the translation of radiochemical methods from one laboratory to another. Impact of 3 different QMA cartridges on the yields of [18F]fluoromethyl tosylate. [ABSTRACT FROM AUTHOR]

18F‐radiolabeled diphenyl gallium thiosemicarbazone was prepared by [18F] fluoride exchange of a nitrato anion under mild conditions. The diphenyl gallium thiosemicarbazone chloride is easily prepared in gram quantities and can be used at room temperature in the presence of oxygen. The corresponding nitrate complex is prepared using silver nitrate in methanol solvent and can be stored under nitrogen for weeks before radiolabeling. The biodistribution of this new tracer was studied in mice using positron emission tomography (PET). [ABSTRACT FROM AUTHOR]

Several structurally related indium chlorido complexes of bis-thiosemicarbazones were prepared, starting from the appropriately substituted bis-thiosemicarbazones, using sodium methoxide in methanol. Detailed NMR studies were conducted to assign the structure including COSY, HSQC, and HMBC techniques. The structures of all indium complexes were solved using single crystal X-ray diffraction. The chlorido ligand was present at the apex of the square pyramidal coordination sphere in all indium complexes. In some complexes, an intermolecular hydrogen bond was present between the chlorine atom and an NH group. Three different indium chlorido complexes were converted into the corresponding fluorido-derivative by a simple halide exchange method using K18F. These novel complexes, containing the positron emitting isotope 18F, may have potential applications in positron emission tomography (PET). Three different indium chlorido complexes were converted into the corresponding fluorido derivative by a simple halide exchange method using K18F. These novel complexes, containing the positron emitting isotope 18F, may have potential applications in positron emission tomography (PET). [ABSTRACT FROM AUTHOR]

A hexan-3,4-dione bis(4N-phenylthiosemicarbazone) gallium nitrate complex was synthesised and the structure was confirmed by NMR studies. The complex was prepared using an appropriately substituted dithiosemicarbazone and sodium methoxide in anhydrous methanol. The structure was further confirmed using single crystal X-ray crystallography. The crystal structure of gallium nitrate complex of diphenylthiosemicarbazone comprise a planar configuration of the tetradentate coordinated thiosemicarbazone with the Ga3+ ion, with the nitrate ligand occupying the apical coordination site. The X-ray structure of the gallium fluoride complex of pentan-2,3-dione bis(4N-phenylthiosemicarbazone) has been determined and confirms exchange of the nitrate can be achieved with fluoride. We show facile exchange of 18F, a positron emitter, to form the 18F-gallium complex under mild conditions, thus providing confirmation that such a transformation can be used to introduce 18F directly into nitrate-coordinated complexes of gallium-thiosemicarbozone complexes, a new labelling strategy for the preparation of imaging agents. [ABSTRACT FROM AUTHOR]

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Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drug Research / Arzneimittel-Forschung (Editio Cantor Verlag fur Medizin und Naturwissenschaften) is the property of Editio Cantor Verlag fur Medizin und Naturwissenschaften and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The in vitro activity profile of stampidine (CAS 217178-62-6, STAMP) was examined against clinical isolates of HIV-1. In a side-by-side comparison against 10 zidovudine-sensitive clinical HIV-1 isolates, STAMP was 100-fold more potent than stavudine (CAS 3056-17-5) and twice as effective as zidovudine (CAS 305 16-87-1). STAMP was also active against pheno-typically and/or genotypically NRTI (nucleoside analog inhibitors of reverse transcriptase) - resistant HIV and inhibited the replication of 20 zidovudine-resistant clinical 11EV-i isolates with low nanomolar to subnanomolar IC[sub50] values. Similarly, STAMP inhibited the replication of 9 genotypically NNRTI (non-nucleoside analog inhibitors of reverse transcriptase) -resistant clinical HIV-1 isolates (n = 9) with an average IC[sub50] value of 11.2 ± 6.5 nmol/L. The remarkable potency of STAMP against clinical HIV-1 isolates with NRTI- or NNRTI -resistance warrants the further development of this promising new antiviral agent. [ABSTRACT FROM AUTHOR]

Examines the toxicity and pharmacokinetics of stampidine, an aryl phosphate derivative of stavudine under development as anti-human immunodeficiency virus agent, in mice and rats. Tolerance of stampide by both mice and rats; Therapeutic micromolar plasma concentrations of stampidine and its active metabolites; In vivo safety of stampidine.