Synthesis of 2, 16α‐ and 4, 16α‐[16α‐<sup>18</sup>F]difluoroestradiols and their 11β‐methoxy derivatives for estrogen receptor imaging
Bibliographic record
Abstract
Abstract We have prepared the 2‐ and 4‐fluoro derivatives of 16α‐[ 18 F]fluoroestradiol (FES) (4a, b) and 11β‐OMe‐FES (4c, d). Electrophilic substitution of estrone or 11β‐OMe‐estrone with N ‐fluoropyridinium salt gave the 2‐and 4‐F derivatives 1, which were converted to the triols 2 and subsequently to the reactive 16β, 17β‐cyclic sulfates 3. Stereoselective opening of the cyclic sulfates via nucleophilic fluorination with Me 4 NF or [ 18 F]F‐ and removal of the protecting ether and sulfate groups via rapid acid hydrolysis gave 4a‐d or [16α‐ 18 F]‐(4a‐d).
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How this classification was reachedexpand
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".