| 研究実績の概要 |
During last year we continue our efforts to improve specific activity of bromo and tosylate N-acetylglucosamine derivatives as precursor for radiosynthesis of N-fluoroacetyl glucosamine ([18F]FAG). Both have already showed similar [18F]F- incorporation rates under microwaves or conventional heating conditions and, there were no significant differences regarding the use of bromo or tosylate precursor for radiosynthesis of [18F]FAG. ESI-MS analysis showed that purification using only amino column was affected by a common byproduct contaminant with similar elution time that final [18F]FAG. Therefore, the inclusion of a C18 bonded silica phase column after the amino-bonded silica phase column improved the specific activity of final [18F]FAG by 10-fold. Nevertheless, two-columns purification process dropped radiochemical yield drastically to approximately 2.3% (bromo) and 0.9% (tosylate). Animal or clinical experiments will be difficult to perform using these yields. Therefore, following the the original plan, the synthesis of a new UDP-glucosamine precursor was started.
The new synthesis scheme include nine reaction steps and six of them were done successfully, but whole synthesis scheme and radiolabelling evaluation was not accomplished under scheduled time. Since all required reagents had already been purchased, completion of synthesis scheme as well as evaluation could be performed in the near future.
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