Pyridazinones from maleic hydrazide: a new substrate for the Mitsunobu reaction
Bibliographic record
Abstract
Crystal engineered organic frameworks assembled using hydrogen bonding are known, and examples constructed from hydroxypyridine/pyridone as the dominant source of hydrogen bonding have been reported. Less explored are analogous systems based on maleic hydrazide. Herein, a two-step route (Mitsunobu followed by Schiff base reactions) to asymmetrically substituted pyridazinones from maleic hydrazide (step 1) is reported with 2-, 3-, or 4-pyridinecarboxaldehyde (step 2). Upon reaction with 4-pyridinecarboxaldehyde, single crystals suitable for analysis via X-ray diffraction were obtained. Careful examination of this solid state structure and comparison with a large number of related structures in the Cambridge Structural Database revealed a pyridazinone (vs. pyridazinol) core and persistent [Formula: see text] “head-to-tail” hydrogen bonded dimers. Although these pyridazinones were originally considered suitable for use as ligands for metal cation coordination, challenges in achieving this outcome were encountered.
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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 | 0.000 |
| 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 | 0.000 |
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".