THE COMPLICATED CONFORMATIONAL LANDSCAPES OF TETRAHYDRO-2-FUROIC DIMER AND MONOHYDRATE: BROADBAND ROTATIONAL SPECTRA AND COMPREHENSIVE CONFORMATIONAL SEARCHES
Bibliographic record
Abstract
Tetrahydro-2-furoic acid (THFA), a chiral carboxylic acid which is often used as a precursor in syntheses of pharmaceuticals, exhibits a complex conformational landscape in its monomeric form.1 Detailed analyses of its conformational distribution and conversion barriers using rotational spectroscopy and theoretical modeling were reported recently.1 In the current study, we focus on investigated how intermolecular interactions with water and THFA itself influence the aforementioned conformational preference. A large number of initial conformational geometries were generated using a semiempirical tight-binding (TB) quantum chemistry code, GFN-xTB, designed for prediction of equilibrium structural properties, such as geometries, vibrational frequencies, and non-covalent interactions.2 The final geometry optimizations were carried out at the B3LYP-D3(BJ)/def2-TZVP, B3LYP-D3(BJ)/6-311++G(2d,p), and MP2/6-311G++(2d,p) levels of theory. Very interestingly, in the THFA monohydrate, the two monohydrates observed contain the most stable THFA monomeric conformer and are ranked the ninth and tenth in terms of their relative energy ordering. On the other hand, the THFA dimer observed contains the third most stable monomeric conformers. We interpret the observed phenomena in terms of the conformational conversion barriers and conformational cooling effects.
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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) | 0.000 | 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".