One-pot synthesis of terpyridines and macrocyclization to <i>C</i><sub>3</sub>-symmetric cyclosexipyridines
Bibliographic record
Abstract
Four examples of 2,6-dicinnamoylpyridines were obtained in 6065% yields in condensations of commercially available 2,6-diacetylpyridine and benzaldehydes in 1:2 stoichiometry. At 2:1 ratios, four related 6,6''-diacetylated-4'-arylterpyridines were isolated in 7073% yields in one-pot condensations in the presence of NH3. 4,4'-Azo benzaldehyde, prepared from nitrobenzaldehyde in three steps and 40% overall yield was similarly converted to a novel azo-linked bis(terpyridine) in 50% yield in a reaction that assembles seven molecules in one step. The 6,6''-diacetylated-4'-arylterpyridines and the correspondingly substituted 2,6-dicinnamoylpyridines were condensed in 1:1 ratio together with NH3 to form 4,4'',4IV-triarylcyclosexipyridines in 2226% yields. These were obtained as mixed Na+ and K+ complexes and were insoluble amorphous solids, except for one example bearing 4-neopentoxyphenyl substituents. 1H NMR showed that the 4,4'',4IV-tri(4-neopentoxyphenyl)cyclosexipyridine complexes form aggregates in solution and at low concentrations show twofold symmetry arising from a loss of planarity.Key words: terpyridines, 4'-aryl-6,6''-diacetylterpyridines, azo-bisterpyridine, cyclosexipyridines, macrocyclization.
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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) | 0.002 | 0.001 |
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".