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A new approach for the synthesis of [ 11 C]‐labeled fatty acids
Author(s) -
Wüst F.,
Dence C. S.,
McCarthy T. J.,
Welch M. J.
Publication year - 2000
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/1099-1344(200011)43:13<1289::aid-jlcr420>3.0.co;2-q
Subject(s) - chemistry , reagent , palmitic acid , alkyl , carbon 14 , fatty acid , organic chemistry , physics , quantum mechanics
The synthesis of ω‐[ 11 C], ω‐1‐[ 11 C] and ω‐3‐[ 11 C] palmitic acid employing a cross‐coupling reaction between a functionalized copper‐zinc reagent with [ 11 C]MeI, [1‐ 11 C]EtI and [1‐ 11 C]BuI is described. A tert ‐butyl‐protected ω‐iodo fatty acid precursor t BuO 2 C‐(CH 2 ) n ‐I (n = 11, 13, 14) was converted into the corresponding dialkylzinc reagent [ t BuO 2 C‐(CH 2 ) n ] 2 Zn which reacts with Me 2 CuI(MgCl) 2 to give a highly reactive copper reagent [ t BuO 2 C‐(CH 2 ) n ] 2 CuI(MgCl) 2 Me 2 Zn as the labeling precursor. The cross‐coupling reaction with [ 11 C]MeI, [1‐ 11 C]EtI and [1‐ 11 C]BuI provided the protected palmitic acid, specifically labeled with carbon‐11 in several positions. The corresponding carbon‐13 labeled compounds were synthesized to verify the labeling position. In a typical synthesis with [1‐ 11 C]EtI starting with 250 mCi of [ 11 C]CO 2 , 14 mCi (6% decay‐corrected based on [ 11 C]CO 2 ) of ω‐1‐[ 11 C]palmitic acid was obtained within 30 minutes after EOB in 88% radiochemical purity prior to purification by HPLC. The general feature of this approach allows the convenient synthesis of palmitic acid specifically labeled in the ω, ω‐1 or ω‐3 positions by using several [ 11 C]‐labeled alkyl iodides ([ 11 C]MeI, [1‐ 11 C]EtI or [1‐ 11 C]BuI) in the same cross‐coupling protocol. Copyright © 2000 John Wiley & Sons, Ltd.