Unexpected <i>N</i>‐Demethylation of Oxymorphone and Oxycodone <i>N</i>‐Oxides Mediated by the Burgess Reagent: Direct Synthesis of Naltrexone, Naloxone, and Other Antagonists from Oxymorphone
Bibliographic record
Abstract
Abstract N ‐Oxides derived from oxycodone and O ‐acyloxymorphone were treated with the Burgess reagent to provide the corresponding oxazolidines in excellent yields. Oxazolidines derived from O ‐acyloxymorphone were further hydrolyzed to noroxymorphone, whose alkylation furnished naltrexone, naloxone, and nalbuphone, which can be converted to nalbuphine, the mixed agonist‐antagonist analgesic. The entire sequence from oxymorphone to the various antagonists was reduced to three one‐pot operations, proceeding in excellent overall yields. In addition, quaternary salts of the oxazolidines with allyl or cyclopropylmethyl groups in fixed equatorial configurations were synthesized. Complete spectral and experimental data are provided for all compounds.
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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) | 0.000 | 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 | 0.001 |
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".