3-{(<i>E</i>)-[4-(4-Hydroxy-3-methoxyphenyl)butan-2-ylidene]amino}-1-phenylurea: crystal structure and Hirshfeld surface analysis
Bibliographic record
Abstract
Two independent molecules (AandB) comprise the asymmetric unit of the title compound, C18H21N3O3. The urea moiety is disubstituted with one amine being linked to a phenyl ring, which is twisted out of the plane of the CN2O urea core [dihedral angles = 25.57 (11) (A) and 29.13 (10)° (B)]. The second amine is connected to an imine (Econformation), which is linked in turn to an ethane bridge that links a disubstituted benzene ring. Intramolecular amine-N—H...N(imine) and hydroxyl-O—H...O(methoxy) hydrogen bonds closeS(5) loops in each case. The molecules have twisted conformations with the dihedral angles between the outer rings being 38.64 (81) (A) and 48.55 (7)° (B). In the crystal, amide-N—H...O(amide) hydrogen bonds link the moleculesAandB viaan eight-membered {...HNCO}2synthon. Further associations between molecules, leading to supramolecular layers in theacplane, are hydrogen bonds of the type hydroxyl-O—H...N(imine) and phenylamine-N—H...O(methoxy). Connections between layers, leading to a three-dimensional architecture, comprise benzene-C—H...O(hydroxy) interactions. A detailed analysis of the calculated Hirshfeld surfaces shows moleculesAandBparticipate in very similar intermolecular interactions and that any variations relate to conformational differences between the molecules.
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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) | 0.002 | 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".