Crystallization of the Racemic Compound and Conglomerate of (<i>RS</i>)-2-Chloromandelic Acid
Bibliographic record
Abstract
( RS )-2-Chloromandelic acid is a new example of chiral compounds that can exist as a racemic compound or a conglomerate depending on the crystallization conditions. Two polymorphic racemic compounds and one conglomerate were disclosed and characterized in this work. Commercially available racemic compound Form α can be prepared by crystallization from nonpolar solvents such as toluene. Freeze-drying leads to a conglomerate formation, Form γ. Crystallization from polar solvents always results in a mixture of Form α and Form γ under our experimental conditions. Thermodynamic calculation of the Gibbs free energy of racemic compound formation demonstrates that the conglomerate Form γ is slightly less stable than the racemic compound Form α. The conglomerate has a tendency to transform into racemic compound by a solid−solid transition. Another metastable racemic compound, Form β, was observed as a single crystal grown from methanol. But bulk crystals of Form β were not obtained.
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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) | 0.001 | 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 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".