Development of a novel [<sup>18</sup>F]fluorobenzyl derivative of the AT<sub>1</sub> receptor antagonist Candesartan
Bibliographic record
Abstract
Candesartan is a clinically approved angiotensin II type 1 receptor (AT 1 R)‐blocker that selectively binds AT 1 Rs in high affinity. We report here the radiosynthesis and automation of the novel [ 18 F]fluorobenzyl derivative of Candesartan using the Sonogashira cross‐coupling reaction. [ 18 F]Fluorobenzyl‐Candesartan ([ 18 F] 7 ) was developed from 4‐[ 18 F]fluoroiodobenzene ([ 18 F]FIB) that was conjugated with alkyne‐trityl‐candesartan with the assistance of a Pd (PPh 3 ) 4 /CuI catalyst followed by acid deprotection. The three‐step two‐reactor 2‐HPLC purification process was automated resulting in >90% pure [ 18 F] 7 in a RCY of 4.6 ± 1.1% (decay corrected from EOB) and molar activities of 1,406‐5,513 GBq/mmol. [ 18 F]FIB was reproducibly obtained by direct radiofluorination of the mono‐iodinated triphenylsulfonium salt in the presence of K222/K 2 CO 3 in an ~30% yield (decay‐corrected). [ 18 F] 7 was stable (>97%) up to 4 h in solution and up to 1 h in rat plasma at 37°C. However, the use of Sonogashira cross‐coupling reaction to produce [ 18 F] 7 in high yields and molar activities was found to be challenging for routine use in radiochemistry labs.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".