Iodination, radioiodination and spectroscopic identification of β-carboline derivatives

Abstract

The synthesis and spectral properties (MS, and NMR) of radioiodinated β‐carbolines: 6‐(I) and 8‐(II) [131I]‐iodo‐1‐methyl‐7‐methoxy‐β‐carboline([131I]‐iodo‐harmine), 6‐(III) and 8‐(IV) [131I]‐iodo‐1‐methyl‐β‐carboline‐7‐ol([131I]‐iodo‐harmol), 8‐[131I]‐iodo‐1‐methyl‐7‐methoxy‐3,4‐dihydro‐β‐carboline(8‐[131I]‐iodo‐harmaline) (V), 8‐[131I]‐iodo‐3,4‐dihydro‐1‐methyl‐β‐carboline‐7‐ol(8‐[131I]‐iodo‐harmalol) (VI), 6‐[131I]‐iodo‐1‐methyl‐β‐carboline(6‐[131I]‐iodo‐harmane) (VII) are described. These are compounds of biological importance and can be used for brain mapping with SPECT technology. Copyright © 1999 John Wiley & Sons, Ltd.

Highly Regioselective Iodination of Arenes via Iron(III)-Catalyzed Activation of N-Iodosuccinimide

“…While the hydrochloride salt gave the same negative outcome, formation of the softer tetrafluoroborate salt by treatment of 5 with tetrafluoroboric acid followed by iodination under the optimized conditions gave PIMBA ( 6 ) in 84% yield over the two steps (Scheme ). This approach was then extended to the synthesis of (−)-IBZM ( 8 ), an imaging agent and antagonist of the human D 2 receptor, and 8-iodoharmaline ( 10 ), a potent monoamine oxidase inhibitor . Again, formation of the tetrafluoro­borate salts, followed by reaction with NIS and the in situ generated Fe­(NTf 2 ) 3 , gave the iodinated products in 47% and 73% overall yield, respectively…”

Radioionidation Reactions for Radio Pharmaceuticals

“…The literature mentions a vast number of tracers, which have been radioiodinated using the copper-assisted method: iodomazindol [79], hippuric and benzoic acid derivatives [67], MIBG [27], iodohippuric acid, IMP, HIPDM [66], iodotropapride [80], piperazine derivatives [81], benzamides [61,69], iodofluvoxamine [82], iodobenzylamine derivatives [83], deltorphin and dermorphin analogues [84], 2a-carbomethoxy-3b-(4'-iodo-phenyl)tropane (b-CIT) [85], vesamicol derivatives [86] and a spiperone analogue (IBSP) [87]. A selection from the wide variety of reaction conditions used for Cu(I)assisted radioiodination is given in Cu(II)-assisted Radioiodination When labelling 2-iodohippuric acid, traces of 2-iodobenzoic acid, which are present in the commercial form of the iodohippuric acid, impair the RCY.…”

“…For example, it has been demonstrated that anisole, toluene and benzene can be radiolabelled via organothallium precursors at the n.c.a level with RCYs ranging from 40% to 70% [27,79,80]. This method has been used for the carrier-added radioiodination of various pharmaceuticals [81][82][83][84][85][86].…”

Silver(I)-Catalyzed Iodination of Arenes: Tuning the Lewis Acidity of N-Iodosuccinimide Activation

“…Aryl iodides are highly important building blocks widely used in total synthesis, medicinal chemistry, and material science. This general versatility is due to the higher reactivity of the C–I bond compared to the corresponding aryl bromide or chloride, allowing their use in highly effective metal-catalyzed cross-coupling reactions and nucleophilic aromatic substitution reactions and for the generation of free-radical intermediates. − Aryl iodides are also found as components in a number of medicinally important compounds such as 8-iodoharmaline ( 1 ), a potent monoamine oxidase inhibitor, and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) ( 2 ), a 5-HT 2A receptor agonist and inhibitor of tumor necrosis factor-α-induced inflammation (Figure ). When used in combination with single photon emission computed tomography (SPECT) imaging, radioiodinated aryl compounds also have significant impact on healthcare, finding application in clinical diagnosis, drug development, and biomedical research .…”