NMR Spectroscopic Studies on the 1:1 Interaction of Tris(hydroxymethyl)phosphine with Cinnamic Acids
Bibliographic record
Abstract
Abstract A 1:1 reaction of (HOCH2)3P with the cinnamic acids ArCH=CHCO2H (Ar = Ph, o‐ and p‐C6H4OH) in acetone at 60 °C affords a phosphobetaine of the type (HOCH2)3P+CH(Ar)CH2CO2– in 70–80 % yields; the products were characterized by 31P{1H}‐, 1H‐, and 13C{1H}‐NMR spectroscopy, and mass spectrometry. In methanol, the compounds decompose partially to a tertiary phosphine of the type (HOCH2)2PCH(Ar)CH2CO2H; the degree of decomposition decreases in the order Ar = o‐C6H4OH > p‐C6H4OH > C6H5. The 1:1 reaction of (HOCH2)3P with cinnamic acid in CD3OD generates (DOCH2)3P+CH(Ph)CH(D)CO2– and (DOCH2)2PCH(Ph)CH(D)CO2D, whereby addition of a deuteron to the α‐C atom is stereospecific and leads to (R,S)‐ and (S,R)‐stereoisomers.
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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) | 0.003 | 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".