1 1C]-Methylchloroformate, a novel [ 1 lcl-acylating agent, was generated in situ from [11C]-methanol and phosgene. To explore the utility of [11C]-methylchloroformate, this agent was reacted with several amines to yield their corresponding [I 1C]-labeled methylcarbamates. The average synthesis (inc
Carbon-11 labelling of an inhibitor of acetylcholinesterase: [11C]physostigmine
β Scribed by S. Bonnot-Lours; C. Crouzel; C. Prenant; F. Hinnen
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- French
- Weight
- 317 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0022-2135
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β¦ Synopsis
Abstract
Physostigmine, an alkaloid from calabar bean is a strong inhibitor of acetylcholinesterase (Ki=3.33 Β± 0.26 Γ 10^β6^M) and has been used clinically in the treatment of glaucoma, atropine intoxication, myasthenia gravis and more recently, in experimental trials in Alzheimer's disease. In order to study the AChE activity in the brain by positron emission tomography, we have undertaken the labelling of physostigmine with carbonβ11. The synthesis involves the reaction of [^11^C]methylisocyanate with eseroline. [^11^C]Methylisocyanate was obtained by heating [^11^C]acetylchloride with tetrabutylammonium azide in toluene. The synthesis of [^11^C]CH~3~COCl involves the carbonation of methylmagnesium bromide in THF with cyclotron produced [^11^C]carbon dioxide and the addition of phthaloyl dichloride. The [^11^C]methylisocyanate is distilled into a solution of eseroline in ether with a small piece of sodium. After 10 minutes at 25Β°C, the solution is purified by HPLC and the appropriate fraction collected.
Starting with 55.5 GBq (1.5 Ci) of [^11^C]carbon dioxide, 0.92β1.48 GBq (25β40 mCi) of [^11^C]Physostigmine are obtained 57 minutes after EOB.
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