Preparation of ω-123I-labelled fatty acids by 123I-for-Br exchange: Comparison of three methods
✍ Scribed by Peter Laufer; Hans-Jürgen MacHulla; Helmut Michael; Heinz Hubert Coenen; Afaf Sayed El-Wetery; Gerd Kloster; Gerhard Stöcklin
- Publisher
- John Wiley and Sons
- Year
- 1981
- Tongue
- French
- Weight
- 361 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0022-2135
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✦ Synopsis
Abstract
Long chain ω‐^123^‐I‐labelled fatty acids such as 16‐I‐hexadecanoic‐, 17‐I‐heptadecanoic‐, and 16‐I‐hexadec‐9‐enoic acid have been prepared without adding carrier by nucleophilic ^123^I‐for‐Br exchange in acetone, in the melt, and by use of phase transfer catalysts in non‐polar solvents. While preparation in refluxing acetone required reaction times of more than 2 hours to reach saturation yields, halogen exchange in molten bromofatty acids at temperatures of about 150 °C gave rise to yields of about 80% of radiochemically pure 17‐^123^I‐heptadecanoic acid within only 5 minutes. Comparable yields were also obtained using Kryptofix 221 in refluxing toluene after 10 minutes.