A Mild Method for Regioselective Labeling of Aromatics with Radioactive Iodine

Abstract

A novel technique to label ortho-, meta-, and para-trimethylsilyl-substituted aryl substituents with radioactive iodide is described. The method takes advantage of the ipso-directing and activating properties of trimethylsilyl substituents on the arenes. The method was demonstrated on a griseofulvin ana-

Radioiodination of 4-benzyl-1-(3-iodobenzylsulfonyl)piperidine, 4-(3-iodobenzyl)-1-(benzylsulfonyl)piperazine and their derivatives via isotopic and non-isotopic exchange reactions

“…These compounds have melting points of 136-137°C and 151-153°C respectively, and because of containing of a strained sulfonamide bonds, they are very unstable in high temperatures as well as nucleophilic conditions. All of our attempts for radioiodination of 4-B-IBSP and 4-IBBSPz with Na 125 I by commonly used methods such as radioiododethallation [4,5], radioiododestannylation [6,7] and radioiododeboronation [8,9] reactions as well as ammonium salts or copper(I)-and copper(II)-assisted radioiodinations [10][11][12][13][14] were unsuccessful. Therefore, we focused on the isotopic and non-isotopic exchange reaction with some modifications.…”

“…Despite the existence of a variety of methods for radioiodination of aromatic compounds such as radioiododethallation, radioiododestannylation, radioiododeboronation and radioiododehalogenation, there are still some structures need to more studies via their labeling, this is due to restrictions on their structural. The aromatic compounds with electron donating groups such as hydroxy, methoxy and amine substituents are radioiodinated by radioiododethallation method in presence of the thallium(III)-tris(trifluoroacetate) in trifluoroacetic acid medium and then by admixing of radioactive iodides [4,5]. One of the most effective and convenient radioiodination methods represents the radioiododestannylation reaction.…”

Injectable iodine-125 labeled tissue marker for radioactive localization of non-palpable breast lesions

“…4 was conducted in GraphPad Prism 7.03 ® in order to reveal significant difference between the groups (please see Results, section 3.3 and the corresponding discussion). Table S1 and S2) and a thallation-iodination protocol was found to be most efficient [22]. The use of thallium is a well-established, mild protocol for electrophilic iodination, but does require rigorous removal of residual thallium during purification.…”

Base‐Mediated Radio‐Iodination of Arenes by Using Organosilane and Organogermane as Radiolabelling Precursors

“…Taking advantage of widely described iododesilylation reactions, some radio‐iododesilylation reactions have been investigated. The reaction generally requires the use of strongly acidic media with heating, oxidant or toxic additives such as TFA (trifluoroacetic acid), [43] tert ‐butylhypochlorite [44–46] or Tl(OCOCF 3 ) 3 [47] . Even if the reaction has been applied to label some investigational radiotracers, [43,48–55] this approach remains scarcely used.…”

“…The reaction generally requires the use of strongly acidic media with heating, oxidant or toxic additives such as TFA (trifluoroacetic acid), [43] tert-butylhypochlorite [44][45][46] or Tl-(OCOCF 3 ) 3 . [47] Even if the reaction has been applied to label some investigational radiotracers, [43,[48][49][50][51][52][53][54][55] this approach remains scarcely used. Radio-iododegermylation reactions have seen limited studies.…”