A One-Pot Synthesis of Functionalized Tetrahydro-4HChromenes and Tetrahydro-4H-Thiopyrans Derivatives
Bibliographic record
Abstract
An efficient approach for the synthesis of functionalized tetrahydro-4H-chromenes 3a-c and tetrahydro-4H-thiopyran 3d-e derivatives moderate to high yields have been achieved via a addition-cyclization reaction of α, β-Unsaturated cyanoesters 1a-c with dimedone 2p or 1, 3-cyclohexandione 2q in presence of sodium ethoxide and Benzaldehyde with 2-propanol in presence of ammonium sulphide respectively.This methodology differs from the previous classical methods in its simplicity and ready availability of the catalyst.The structures of the compounds 3a-e were confirmed by their ultraviolet, infrared, 1 H NMR, 13 C NMR and elemental analyses.
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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) | 0.003 | 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".