Book/Report

FZJ-2018-01941

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Untersuchungen zur elektrophilen Radiobromierung und -iodierung aromatischer Verbindungen mit N-Halogenverbindungen ohne Trägerzusatz

Petzold, G. S. (Corresponding author)FZJ*

1982
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/17705

Report No.: Juel-1810

Abstract: There is a special need for radiohalogenated compounds for diagnostic nuclear medicine, in particular for no-carrier-added (nca) short lived cyclotron products. In this study the applicability of chloramine-T (CAT) and dichloramine-T (DCT) has been demonstrated for nca-radiohalogenation with bromine-75,77 and iodine-123 in aqueous and organic solvents. Radio gaschromatography and -HPLC are used for product analysis. In aqueous solution the optimum reaction conditions with respect to pH, concentration of CAT, reaction time and added bromide-carrier are determined using tyrosine as a model substrate. The suitability of the CAT method for radiobrominations under convenient and mild conditions is demonstrated for some biomolecules such as amino acids and nucleobases as well as for peptides and the proteins urokinase and HSA. High radiochemical yields (up to 85%) are obtained in the case of activated aromatic systems. Studies on reactivity and selectivity of the radiohalogenation reaction in the aqueous solution show that there are different reaction mechanisms which depend on the pH of the solution. At pH 1 the reacting species are predominantly the interhalogens IC1 or BrCl, whereas at pH 7 the reaction probably proceeds via the N-iodo- or N-bromosulfonamide. Dichloramine-T is found to be a new efficient reagent for radiobromination and -iodination of aromatic compounds in various organic solvents such as acetic acid, dichloromethane or carbon tetrachloride. A high para-selectivity is observed and the radiochemical yields (80%) are as high as in aqueous solution. A comparison of this reagent with different in-situ halogenation agents shows that DCT is superior with respect to reaction time, concentration of the reagent and thus oxidative side reactions, and ease of handling. Another application of DCT is the radiohalogenation of olefins via electrophilic addition. The added radiohalogen species are generated in-situ from DCT and radiohalide. By choosing the appropriate solvent, the 1-halo-2-methoxy- (in methanol) or 1-halo-2-chloro- (in CH 2 Cl 2 ) addition products are formed with such olefins as cyclohexene (70%) and tri-0-acetyl-Dglucal (75%).

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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