Synthesis and crystal structures of 3-hydroxy-2,4-dimethyl-2<i>H</i>-thiophen-5-one and 3-hydroxy-4-methyl-2<i>H</i>-thiophen-5-one
Bibliographic record
Abstract
The structures of two hydroxy-thiophenone derivatives related to the antibiotic thiolactomycin are presented. These are the racemic 3-hydroxy-2,4-dimethyl-2 H -thiophen-5-one, C 6 H 8 O 2 S, and 3-hydroxy-4-methyl-2 H -thiophen-5-one, C 5 H 6 O 2 S. The main structural feature of both compounds is C (6) hydrogen-bonded chains formed between the OH and C=O groups. In achiral C 5 H 6 O 2 S, these chains propagate only by translation, corresponding to x + 1, y , z + 1. However, in contrast, for racemic C 6 H 8 O 2 S the hydrogen-bonded chains propagate through a − x + {3\over 2}, y + {1\over 2}, z operation, giving chains lying parallel to the crystallographic b -axis direction that are composed of alternate R and S enantiomers. The crystals of 3-hydroxy-4-methyl-2H-thiophen-5-one were found to be twinned by a 180° rotation about the reciprocal 001 direction. In the final refinement the twin ratio refined to 0.568 (2):0.432 (2).
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.004 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| 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".