A simplified radiosynthetic approach to 18F-labelling BODIPY dyes using indium salts as ideal Lewis acid mediators
Bibliographic record
Abstract
A B S T R A C T Indium salts were used to facilitate 18 F-for- 19 F isotopic exchange in solutions containing meso -methyl- or meso -phenol- bearing BODIPY dyes and dried tetraalkylammonium [ 18 F]fluorides. Aqueous [ 18 F]F - was trapped on cationic quaternary methyl ammonium (QMA) anion exchange sorbent with carbonate anion and extracted using non-basic chloride or triflate. Evaporative concentration of the eluates at 110 0 C resulted in a negligible loss of radioactivity due to [ 18 F]HF generation [80-98% decay-corrected (DC) retention in activity], despite the absence of the basic carbonate and bicarbonate anions that are canonically used to strip [ 18 F]F - from QMA resins. Treatment of the two model BODIPY dyes in either CH 2 Cl 2 or CH 3 CN afforded their 18 F-labelled analogues in DC radiochemical yields of 47-60% after solid-phase extraction (SPE) purification. In addition, [ 18 F]F - elution from anion exchange sorbent and Lewis acid activation were consolidated by employing In(OTf) 3 for both steps, albeit at a cost of increased loss of [ 18 F]HF during the azeotropic evaporation process (3 portions of CH 3 CN; 60±8% DC retention after dry-down). Finally, [ 18 F]BODIPY synthesis could be achieved by simply concentrating the 19 F dyes in CH 3 CN-H 2 O mixtures of In(OTf) 3 -eluted [ 18 F]F - , followed by resolubilization in CH 3 CN and finally C 18 SPE purification. This constitutes a rapid and ultra-simple 18 F-labelling protocol that is amendable to automated synthesis (27-39 % DC radiochemical yields, 50-73 min total synthesis time). In summary, indium salts bring significant improvements to this methodology by overcoming the serious instability and toxicity associated with SnCl 4 . This methodology enables the facile conversion of BODIPY dyes into dual-modal fluorescence and positron emission tomography (PET) imaging agents.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".