Trifluoromethanesulfonic acid, an alternative solvent medium for the direct electrophilic fluorination of DOPA: new syntheses of 6‐[<sup>18</sup>F]fluoro‐<scp>L</scp>‐DOPA and 6‐[<sup>18</sup>F]fluoro‐<scp>D</scp>‐DOPA
Bibliographic record
Abstract
Abstract Previous work from this laboratory has shown that the direct fluorination of 3, 4‐dihydroxy‐phenyl‐L‐alanine (L‐DOPA) in anhydrous HF (aHF) or BF3/HF with F2 is an efficient method for the synthesis of 6‐fluoro‐L‐DOPA. Since then, 18F‐labeled 6‐fluoro‐L‐DOPA ([18F]6‐fluoro‐L‐DOPA) has been used to study presynaptic dopaminergic function in the human brain and to monitor gastrointestinal carcinoid tumors. This work demonstrates that the reactivity and selectivity of F2 toward L‐DOPA in CF3SO3H is comparable with that in aHF. This new synthetic procedure has led to the production of [18F]fluoro‐L‐DOPA and [18F]fluoro‐D‐DOPA isomers in 17±2% radiochemical yields (decay corrected with respect to [18F]F2). The 2‐ and 6‐FDOPA isomers were separated by HPLC and subsequently characterized by 19F NMR spectroscopy. The corresponding [18F]‐FDOPA enantiomers have been obtained in clinically useful quantities by a synthetic approach that avoids the use of aHF. Copyright © 2007 John Wiley & Sons, Ltd.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".