Radioiodinated analogs of xylamine: N-(2-chloroethyl)-N-ethyl-2-[125I]iodobenzylamine and N,N-diethyl-2-[125I]iodobenzylamine as potential tools for monoamine uptake exploration by spect
✍ Scribed by C. Branger; L. Garreau; Y. Frangin; S. Chalon; P. Dubois; A.-M. Dognon; J.-E. Ombetta-Goka; J.-C. Besnard; D. Guilloteau
- Book ID
- 102901527
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- French
- Weight
- 615 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0022-2135
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✦ Synopsis
Abstract
In order to improve the scintigraphy and radiotherapy of neuroendocrine tumors we synthesized two radioiodinated benzylamines [N‐(2‐chloroethyl)‐N‐ethyl‐2‐[^125^I]iodobenzylamine and N,N‐diethyl‐2‐[^125^I]iodobenzylamine], analogs of xylamine [N‐(2‐chloroethyl)‐N‐ethyl‐2‐methylbenzylamine]. Xylamine is an irreversible inhibitor of uptake and accumulation of noradrenaline. The two unlabelled iodinated derivatives [N‐(2‐chloroethyl)‐N‐ethyl‐2‐iodobenzylamine and N,N‐diethyl‐2‐iodobenzylamine] were synthesized, purified and checked by HPLC, NMR and mass spectrography. Their affinity for the noradrenaline transporter was determined in vitro on rat brain membrane homogenates with [^3^H]nisoxetine. Radioiodination was performed by iodide for bromide nucleophilic exchange from brominated precursors. The N,N‐diethyl‐2‐[^125^I]iodobenzylamine was obtained directly from N,N‐diethyl‐2‐bromobenzylamine. Radiosynthesis of N‐(2‐chloroethyl)‐N‐ethyl‐2‐[^125^I]iodobenzylamine required three steps. A new brominated precursor [N‐ethyl‐N‐(2‐bromobenzyl)glycine ethyl ester] which was stable for radiolabelling and suitable for reduction to N‐(2‐hydroxyethyl)‐N‐cthyl‐2‐[^125^I]iodobenzylamine was synthesized. N‐(2‐Hydroxyethyl)‐N‐ethyl‐2‐[^125^I]iodobenzylamine was converted to N‐(2‐chloroethyl)‐N‐ethyl‐2‐[^125^I]iodobenzylamine in the presence of an excess of thionyl chloride. Radioiodinated derivatives were purified and checked by HPLC.