Directed sequential synthesis of conjugated linoleic acid isomers from Δ<sup>7, 9</sup> to Δ<sup>12, 14</sup>
Why this work is in the frame
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Bibliographic record
Abstract
Abstract Position and configuration isomers of conjugated linoleic acid (CLA), from 7, 9‐ through 12, 14‐C18:2, were synthesized by directed sequential isomerizations of a mixture of rumenic ( cis ‐9, trans ‐11 C18:2) and trans ‐10, cis ‐12 C18:2 acids. Indeed, the synthesized conjugated fatty acids cover the range of unsaturated systems as found in milk fat CLA. The two‐step sequence consisted in initial sigmatropic rearrangement of cis/trans CLA isomers at 200 °C for 13 h under inert atmosphere (Helium, He), followed by selenium‐catalyzed geometrical isomerization of double bonds at 120 °C for 20 h under He. Product analysis was achieved by gas‐liquid chromatography using a 120 m polar capillary column coated with 70% cyanoalkylpolysiloxane equivalent polymer. Migration of conjugated systems was geometrically controlled as follows: the cis ‐C n , trans ‐C n+2 double bond system was rearranged through a pericyclic [1, 5] sigmatropic mechanism into a trans ‐C n‐1 , cis ‐C n+1 unsaturated system, while the trans ‐C n , cis ‐C n+2 double bond system was rearranged through a similar pericyclic mechanism into a cis ‐C n+1 , trans ‐C n+3 unsaturated system. Selenium‐catalyzed geometrical isomerization under mild conditions then allowed cis/trans double bond configuration transitions, resulting in the formation of all cis , all trans , cis‐trans and trans‐cis isomers. A sequential combination of the two reactions resulted in a facile controlled synthesis of CLA isomers, useful for the chromatographic identification of milk fat CLA, as well as for the preparation of CLA standard mixture.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it