Synthesis of NCA [carbonyl-11C]amides by direct reaction of in situ generated [11C]carboxymagnesium halides with amines under microwave-enhanced conditions
✍ Scribed by Shui-Yu Lu; Jinsoo Hong; Victor W. Pike
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- French
- Weight
- 119 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0022-2135
- DOI
- 10.1002/jlcr.786
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✦ Synopsis
Abstract
No‐carrier‐added (NCA) aromatic and aliphatic [carbonyl‐^11^C]amides were rapidly (<5 min) synthesized in one pot in useful radiochemical yields (20–65%, decay‐corrected) by directly coupling amines with NCA [^11^C]carboxyhyphenmagnesium halides generated in situ from Grignard reagents and cyclotron‐produced [^11^C]carbon dioxide. In this system cyclohexylcarboxymagnesium chloride (1b) is more reactive than 4‐fluorophenylcarboxymagnesium bromide (2b) and primary amines (e.g. aniline, aminopyridines) far more reactive than secondary amines (e.g. 2‐(methylamino)pyridine). The scope of the reaction was widened considerably by the application of microwaves, which allowed reactions to be carried out at much higher temperature than the boiling point of the solvent (i.e. tetrahydrofuran, b.p. 67°C). Copyright © 2003 John Wiley & Sons, Ltd.