Three hexahydropyridopyrimidine-spiro-cyclohexanetriones: supramolecular structures generated by O—H...O, N—H...O, C—H...O and C—H...π hydrogen bonds, and π–π stacking interactions
Bibliographic record
Abstract
4',4'-Dimethyl-2-methylsulfanyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1'-cyclohexane-2',4,6'-trione, C(15)H(19)N(3)O(3)S, (I), has a markedly polarized molecular-electronic structure, and the molecules are linked into a three-dimensional framework by a combination of N-H.O, C-H.O and C-H.pi hydrogen bonds. 8-Hydroxymethyl-4',4'-dimethyl-2-methylsulfanyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1'-cyclohexane-2',4,6'-trione, C(16)H(21)N(3)O(4)S, (II), where the hydroxymethyl substituent is disordered over two sets of sites, has a much less polarized structure than (I); the molecules are linked by a combination of O-H.O and N-H.O hydrogen bonds into chains containing alternating R(2)(2)(8) and R(2)(2)(16) rings, and these chains are linked into sheets by a combination of a pi-pi stacking interaction and a C-H.O hydrogen bond. 8-Ethoxymethyl-2-methoxy-4',4'-dimethyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1'-cyclohexane-2',4,6'-trione, C(18)H(25)N(3)O(5), (III), has an unpolarized electronic structure, and a combination of N-H.O, C-H.O and C-H.pi hydrogen bonds links the molecules into sheets.
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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".