Modification of the vinylogous aldol condensation – Another approach to the synthesis of C(15)‐alkylidene and benzylidene andrographolide derivatives
Bibliographic record
Abstract
Abstract A two‐step protocol for the synthesis of 15‐alkylidene and benzylidene derivatives of 14‐deoxy‐11,12‐didehydroandrographolide, which was conducted through a dehydration reaction of andrographolide and a vinylogous aldol condensation between α,β‐unsaturated butenolide moiety and benzaldehyde derivatives has been developed. Combining with various experiments on new catalysts for these reactions: the dehydration of andrographolide by concentrated H2SO4 and the vinylogous aldol reaction by K2CO3 in MeOH or a mixture of CH3COOH/pyrrolidine in MeOH, this research has determined the optimized conditions for those catalysts and the new approach to this aldol‐like reaction. All compounds synthesized were characterized by the analysis of IR, NMR, HRMS spectra.
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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".