Stereochemical basis for activity in thiadiazole anticonvulsants: 1-[5-(biphenyl-2-yl)-1,3,4-thiadiazol-2-yl]methanaminium chloride and two inactive analogues, 2-(biphenyl-4-yl)-5-[2-(1-methylethylidene)hydrazino]-1,3,4-thiadiazole and the methanol solvate of its hydrochloride salt
Bibliographic record
Abstract
In 1-[5-(biphenyl-2-yl)-1,3,4-thiadiazol-2-yl]methanaminium chloride, C15H14N3S+.Cl-, the protonation occurs at the amine N atom. The outer phenyl ring makes an angle of 88.0 (2) degrees with the plane through the inner benzene ring, and the planes of the thiadiazole ring and the attached benzene ring intersect at an angle of 165.5 (4) degrees . In addition to classical N-H...N and N-H...Cl(-) hydrogen bonds producing chains parallel to the c axis, there are weak C-H...N and C-H...Cl- hydrogen bonds. The hydrogen bonds and packing interactions result in hydrophilic and hydrophobic planar areas in the crystal, perpendicular to the a axis. Stereochemical comparison with phenytoin shows that the two compounds may utilize similar mechanisms of action. 2-(Biphenyl-4-yl)-5-[2-(1-methylethylidene)hydrazino]-1,3,4-thiadiazole, C17H16N4S, where Z' = 2, and the methanol solvate of its hydrochloride salt, 5-(biphenyl-4-yl)-2-[2-(1-methylethylidene)hydrazino]-1,3,4-thiadiazol-3-ium chloride methanol solvate, C17H17N4S+.Cl-.CH3OH, adopt linear almost planar molecular conformations. The para position of the outer phenyl ring in these compounds precludes adoption of the phenytoin anticonvulsant stereochemistry.
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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) | 0.003 | 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".