Synthesis of trichiliasterones A and B 16-Ketosteroids isolated from <i>Trichilia hirta</i> and <i>Trichilia americana</i>
Bibliographic record
Abstract
The syntheses of trichiliasterone A (3β-hydroxypregnan-2,16-dione) and trichiliasterone B (2-hydroxyandrost-1,4-diene-3,16-dione) have been carried out starting from isoandrosterone and testosterone acetate, respectively. In each synthesis the functionality in the D ring was installed prior to working on ring A. In the case of trichiliasterone A, the D ring chemistry involved a Wittig reaction to generate the 17-methylene group, followed by SeO2 oxidation to give an α,β-unsaturated ketone. Reaction with lithium dimethyl cuprate gave the required 17-ethyl-16-keto functionality. A 2,3-epoxy enol acetate served as the key intermediate for the generation of the 2-keto-3-hydroxy functions in ring A. The transposition of the keto function from C-16 to C-17 in the synthesis of trichiliasterone B was accomplished via oxymercurationdemercuration of the Δ1617 double bond followed by oxidation. The hydroxyl group at C-2 and the additional ring A unsaturation were introduced by lead tetra-acetate treatment of the 3-keto-4-enone function and subsequent air oxidation.Key words: 16-ketosteroids, plant steroids, Trichilia hirta, trichiliasterones.
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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 | 0.001 | 0.001 |
| 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 | 0.001 |
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".