Synthesis of Non-Peptidyl α,α-Difluoromethylenephosphonic Acids on a Soluble Polymer Support
Bibliographic record
Abstract
The polymer-supported syntheses of a series of biaryl derivatives bearing the alpha,alpha-difluoromethylenephosphonic acid group is reported. Non-cross-linked polystyrene (NCPS) was used as the support which enabled the reactions to be carried out under homogeneous conditions and reactions to be followed using conventional (19)F NMR. Synthesis of the biaryl phosphonic acids was initiated by attaching mono-ethyl esters of alpha, alpha-difluorophosphonic acids 11 and 12 to 3% alkylhydroxy-modified NCPS via a phosphate ester linkage. Suzuki reaction conditions were developed which allowed for the formation of a series of polymer-bound biaryl phosphonates at ambient temperature. Removal of phosphonic acids from the support and cleavage of the ethyl protecting group was achieved in a single step using TMSI or TMSBr. Yields of the phosphonic acids ranged from 43 to 89% and, in most cases, were obtained in a purity (96-99%), after cleavage from the support, that was sufficient for biological screening.
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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 | 0.000 | 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".