Efficient <i>in‐loop</i> synthesis of high specific radioactivity [<sup>11</sup>C]carfentanil
Why this work is in the frame
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Bibliographic record
Abstract
Abstract The synthesis of the precursor for [ 11 C]carfentanil and the precursor labelling with 11 C have both been improved. The problem ‘bottleneck’ step in the carfentanil precursor synthesis, due to low chemical yield (14%) of intermediates nitrile into amide conversion, has been solved. Application of a H 2 O 2 /K 2 CO 3 /DMSO reaction method significantly increased the yield of this chemical transformation (up to 84%). A simple and straight‐forward synthesis of [ 11 C]carfentanil was achieved by combining in‐loop methylation of the ammonia salt of the precursor by [ 11 C]CH 3 I, using tetrabutylammonium hydroxide as a base, with a previously developed product purification procedure using a C2 extraction disc. A decay corrected yield with respect to [ 11 C]CH 3 I of [ 11 C]carfentanil was 64±12% ( n =6) with the synthesis time of 21 min. The radiochemical purity was >98%. Comparatively high specific radioactivity of [ 11 C]carfentanil [11.2±4.8 Ci/μmol (EOS, n =5)] was partially attributed to the use of [ 11 C]methane target gas for production of carbon‐11 methyl iodide. Copyright © 2003 John Wiley & Sons, Ltd.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it