Steric Effects in Benzopyran Imine‐Hemiaminal Ring–Chain Tautomerism: Tautomeric Free Energies as a Measure of Substituent Size
Bibliographic record
Abstract
Abstract We have synthesized and characterized a series of tetrahydrobenzo[c]pyranamines that exist in an imine/hemiaminal ring–chain tautomerism. As was the case for a series of homologous isobenzofuranamines, their tautomeric free energies were found to vary depending on the steric bulk of common substituents. The results indicate that even for systems of differing ring size, tautomeric free energies give consistent values of the steric bulk of substituents. Six single‐crystal X‐ray diffraction structures have been determined, two on tetrahydrobenzo[c]pyranamines and one on an open‐chain tautomer. Two further on dihydrobenzo[c]furanamines and one open‐chain tautomer of this system. H‐atoms have been placed close to the neutron positions using refinement with aspherical atomic scattering factors and a detailed analysis of H‐bonding was undertaken.
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How this classification was reachedexpand
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 | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".